ELECTRODE ASSEMBLY FOR ARC WELDING

The disclosed technology generally relates to welding technologies and more particularly to electrode assemblies for arc welding, e.g., submerged arc welding. In one aspect, an electrode assembly for submerged arc welding comprises a contact tip portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough. During welding, the contact tip portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode. The extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating material surrounding the consumable electrode.

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Description
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.

This application claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63/264,358, entitled ELECTRODE ASSEMBLY FOR ARC WELDING, filed Nov. 19, 2021, and to U.S. Provisional Patent Application No. 63/370,430, entitled ELECTRODE ASSEMBLY FOR ARC WELDING, filed Aug. 4, 2022. The entirety of each of the above applications is hereby incorporated by reference herein.

BACKGROUND Field

The disclosed technology generally relates to welding technologies and more particularly to electrode assemblies for arc welding, e.g., submerged arc welding.

Description of the Related Art

Various welding technologies utilize welding wires that serves as a source of metal. For example, in metal arc welding, an electric arc is created when a voltage is applied between a consumable weld electrode wire, which serves as one electrode that advances towards a workpiece, and the workpiece, which serves as another electrode. The arc melts a tip of the metal wire, thereby producing droplets of the molten metal wire that deposit onto the workpiece to form a weldment or weld bead.

Technological and economic demands on welding technologies continue to grow in complexity. For example, the need for higher bead quality in both appearance and in mechanical properties continues to grow, including high yield strength, ductility and fracture toughness. Simultaneously, the higher bead quality is often demanded while maintaining economic feasibility. Some welding technologies aim to address these competing demands by improving the consumables, e.g. by improving the physical designs and/or compositions of the electrode wires.

Submerged arc welding (SAW) can provide highly economic solutions for some applications. The high deposition rates attained with submerged arc are chiefly responsible for the economies achieved with the process.

SUMMARY OF THE INVENTION

In an aspect, an electrode assembly for submerged arc welding (SAW) comprises a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode. The extension portion is elongated in a wire feed direction and is configured to electrically insulate the consumable electrode from a work piece during welding with an insulating sleeve surrounding the consumable electrode. The electrode assembly is configured such that, during SAW with consumable electrode inserted therethrough, a ratio between an electrical stick-out distance, which is measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, and a diameter of the electrode exceeds 30.

In another aspect, an electrode assembly for submerged arc welding, comprises a head portion and an extension portion arranged serially with the head portion, wherein the head portion and the extension portion are configured to feed a consumable electrode therethrough. The extension portion is configured to be disposed closer to an arcing tip of the consumable electrode relative to the head portion and comprises an envelope formed of a nonmagnetic material and an insulating sleeve disposed within the envelope and comprising a solid insulating material configured to surround the consumable electrode.

In another aspect, an extension portion configured for a submerged arc welding electrode assembly comprises an envelope formed of a nonmagnetic material and an insulating sleeve disposed within the envelope and comprising a solid insulating material configured to surround a consumable electrode. The extension portion is configured to be arranged serially with a head portion of the electrode assembly and to receive a consumable electrode from the head portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a submerged arc welding (SAW) system according to embodiments of the present technology.

FIG. 2 illustrates a conventional electrode assembly for a SAW system.

FIG. 3A illustrates a conventional electrode assembly for a SAW system over a workpiece having a shallow groove.

FIG. 3B illustrates a long stick-out (LSO) electrode assembly for a SAW system over a workpiece having a shallow groove.

FIG. 4A illustrates a conventional electrode assembly for a SAW system over a workpiece having a deep groove.

FIG. 4B illustrates an LSO electrode assembly for a SAW system over a workpiece having a deep groove.

FIG. 5 is a graph showing an experimental comparison of deposition rates versus current for both conventional SAW assemblies and LSO SAW assemblies.

FIGS. 6A-6C depict perspective views of an LSO electrode assembly having an extension portion according to embodiments of the present technology.

FIG. 7A is an isometric view of an LSO extension portion according to embodiments of the present technology.

FIG. 7B is an exploded view of the LSO extension portion depicted in FIG. 7A.

FIG. 7C is a perspective view of an envelope or nozzle body for an LSO extension portion according to embodiments of the present technology.

FIG. 7D is a cross-sectional view of the envelope or nozzle body depicted in FIG. 7C taken along line A-A.

FIG. 7E depicts a perspective view of an insulating sleeve for an LSO extension portion according to embodiments of the present technology.

FIG. 7F is a cross-sectional view of the nozzle body depicted in FIG. 7E taken along line B-B.

FIG. 8 is a cross-sectional view of an LSO extension portion according to embodiments of the present technology.

FIGS. 9A and 9B show multi-arc LSO SAW assemblies according to embodiments of the present technology.

 DETAILED DESCRIPTION

In processes using a consumable electrode, the electrode or the wire melts to provide an additive metal that fills a gap to form a weld joint that joins two metal workpieces. The welding processes using consumable electrodes include shielded metal arc welding (SMAW), gas metal arc welding (GMAW) or metal inert gas (MIG) welding, flux-cored arc welding (FCAW), metal-cored arc welding (MCAW), and submerged arc welding (SAW), among others.

Submerged Arc Welding

FIG. 1 schematically illustrates a submerged arc welding (SAW) system 100 for depositing a filler or weld metal onto a workpiece 102. The system 100 includes a bare metal electrode wire 104 having a tip 106, a contact tip 110 coupled to the electrode 104, and a power supply 108, which is electrically coupled to the contact tip 110 and the workpiece 102. The system 100 also includes a flux delivery system 112, which is configured to dispense flux 114 onto the workpiece 102 during the SAW process. The electrode 104 generally comprises a metal or alloy while the flux comprises granular fusible material. During the SAW process, heat is derived from an arc 116 between a bare metal electrode 104 and a workpiece 102. The arc is shielded by a blanket of the flux 114 which is placed over the joint area ahead of the arc 116. Filler metal is obtained primarily from the electrode wire 104 which is continuously fed through the blanket of flux 114 into the arc 116 and pool 122 of molten flux. Additional filler metal may be obtained by adding cold wire to the weld pool 122 or from metal powder contained in the flux 114. Accordingly, in SAW, unlike the other fluxed processes, two consumables (the electrode wire 104 and the flux 114) are used and these two consumables may be supplied separately.

The distinguishing feature of SAW is the flux 114, which covers the weld area and prevents arc radiation, sparks, spatter and fumes from escaping. The flux 114 allows for achieving high deposition rates and high quality weld deposit characteristics. In addition to shielding the arc 116 from view, the flux 114 provides a slag 118 which protects the weld metal 120 as it cools, deoxidizes and refines the weld metal 120, insulates the weld to reduce the cooling rate and helps shape the weld contour.

During the SAW process, the heat of the arc 116 melts some of the flux 114 along with the tip 106 of the electrode 104 to form a weld pool 122, as illustrated in FIG. 1. The tip 106 of the electrode 104 and the welding zone are always surrounded and shielded by molten flux 114, which is itself covered by a layer of unfused flux 114. The electrode 104 is held a short distance above the workpiece 102 with the arc 116 forming between the electrode 104 and the workpiece 102. As the electrode 104 progresses along the joint, the lighter molten flux 114 rises above the molten metal in the weld pool 122 as slag 118. The molten metal in the weld pool 122, which has a higher melting (freezing) point, solidifies while the slag 118 above it is still molten. The slag 118 then freezes over the newly solidified weld metal 120, continuing to protect the metal 120 from contamination while it is very hot and would react with atmospheric oxygen and nitrogen. After cooling and removing any unfused flux 114 for reuse, the solidified slag 118 may be easily removed from the weld.

The power supply 108 generates a voltage and current for the system 100 and the voltage and current are applied to the workpiece 102 and the electrode 104. The current is applied to the electrode via the contact tip 110. High currents can be used in submerged arc welding and extremely high heat can be generated. Because the current is applied to the electrode 104 a short distance above its tip 106, relatively high amperages can be used on small diameter electrodes. This results in extremely high current densities on relatively small cross sections of electrode. Currents as high as or exceeding 600 amperes can be carried on electrodes as small as 64″, giving a density in the order of 100,000 amperes per square inch six to ten times that carried on stick electrodes.

Because of the high current density, the melt off rate is much higher for a given electrode diameter than with stick-electrode welding. The melt-off rate is affected by the electrode material, the flux 114, type of current, polarity, and length of wire beyond the point of electrical contact in the gun or head.

Submerged arc welding may be performed with either DC or AC power. Direct current gives better control of bead shape, penetration, and welding speed, and starting is relatively easier. Bead shape is usually best with DC electrode positive (DCEP or reverse polarity), which also provides maximum penetration. Highest deposition rates and minimum penetration can be obtained with DC electrode negative (DCEN). Alternating current minimizes arc blow and gives penetration between that of DCEP and DCEN.

The insulating blanket of flux 114 above the arc 116 prevents rapid escape of heat and concentrates it in the welding zone. Not only are the electrode 104 and base metal of the workpiece 102 melted rapidly, but the fusion is deep into the base metal. The deep penetration allows the use of small welding grooves, thus minimizing the amount of filler metal per foot of joint and permitting fast welding speeds. Fast welding, in turn, minimizes the total heat input into the assembly and, thus minimizes problems of heat distortion. Even relatively thick joints can be welded in one pass by submerged arc welding.

Welds made under the protective layer of flux 114 have good ductility and impact resistance and uniformity in bead appearance. Mechanical properties at least equal to those of the base metal are consistently obtained. In single-pass welds, the fused base material is large compared to the amount of filler metal used. Thus, in such welds the base metal may greatly influence the chemical and mechanical properties of the weld. For this reason, it is sometimes unnecessary to use electrodes of the same composition as the base metal for welding many of the low-alloy steels. However, the chemical composition and properties of multipass welds are less affected by the base metal and depend to a greater extent on the composition of the electrode, the activity of the flux, and the welding conditions.

Through regulation of current, voltage, and travel speed, the operator can exercise close control over penetration to provide any depth ranging from deep and narrow with high-crown reinforcement, to wide, nearly flat beads with shallow penetration. Beads with deep penetration may contain on the order of 70% melted base metal, while shallow beads may contain as little as 10% base metal. In some instances, the deep-penetration properties of submerged arc welding can be used to eliminate or reduce the expense of edge preparation.

The flux serves several functions in submerged arc welding. These include covering the molten weld metal to protect it from the atmosphere and acting as a slag which refines the molten deposit by scavenging oxides and other non-metallic inclusions. Metallic additions to the flux can add to the alloy content of the deposit and deoxidize it.

There are four types of fluxes based on their method of manufacture; fused, bonded, agglomerated and mechanically mixed.

Fluxes are also identified as basic, acid, and neutral. Basic fluxes contain oxides of metals which dissociate easily while acidic fluxes contain oxides which dissociate to a small extent. A neutral flux does not add or subtract from the composition of the weld deposit. Fluxes having a ratio of CaO or MnO to SiO2 which is greater than one are considered basic, those near one are considered neutral, and those less than one are acidic.

With proper selection of equipment, submerged arc is widely applicable to the welding requirements of industry. It can be used with all types of joints, and permits welding a full range of carbon and low alloy steels, from 16-gage sheet to the thickest plate. It is also applicable to some high-alloy, heat-treated, and stainless steels, and is a favored process for rebuilding and hard surfacing. Any degree of mechanization can be used—from the hand-held semi-automatic gun to boom or track-carried and fixture held multiple welding heads.

The high quality of submerged arc welds, the high deposition rates, the deep penetration, the adaptability of the process to full mechanization, and the comfort characteristics (no glare, sparks, spatter, smoke, or excessive heat radiation) make it a preferred process in steel fabrication. It is used extensively in ship and barge building, railroad car building, pipe manufacture, and in fabricating structural beams, girders, and columns where long welds are required. Automatic submerged arc installations are also key features of the welding areas of plants turning out mass-produced assemblies joined with repetitive short welds.

Other factors than deposition rates enter into the lowering of welding costs. Continuous electrode feed from coils, ranging in weight from 60 to 1,000 pounds, contributes to a high operating factor. Where the deep-penetration characteristics of the process permit the elimination or reduction of joint preparation, expense is reduced. After the weld has been run, cleaning costs are minimized, because of the elimination of spatter by the protective flux.

When submerged-arc equipment is used properly, the weld beads are smooth and uniform, so that grinding or machining are rarely required. Since the rapid heat input of the process minimizes distortion, the costs for straightening finished assemblies are reduced, especially if a carefully planned welding sequence has been followed. Submerged arc welding, in fact, often allows the pre-machining of parts, further adding to fabrication cost savings.

Because of these and other advantages provided by SAW, there is a desire and need to further improve various aspects of SAW, including even higher productivity and weld quality. For example, as one of the technical advantages of SAW derives from preheating the consumable electrode, there is a desire and need to further improve the preheating arrangement through improved electrode assembly design.

Long Stick-Out Electrode Assembly for Submerged Arc Welding

FIG. 2 illustrates an electrode assembly 200 defining an electrical stick-out and positioned over a workpiece 202. The electrode assembly 200 includes a head portion 204 configured to receive a consumable electrode 206. The head portion 204 includes a contact tip 210, an electrode guide tube 212, and an insulated guide 214. The contact tip 210 is disposed radially around the electrode 210 and is configured to transfer current from a power source (e.g., power source 108 shown in FIG. 1) to the electrode 206. The electrode 206 includes a tip portion 208 configured to extend beyond the head portion 204. The portion of the electrode 206 that extends between the end portion 208 and the end of the head portion 204 is referred to as the visible stick-out 218 while the portion of the electrode 206 that extends between the tip portion 208 and the contact tip 210 is referred to as the electrical stick-out or electrical electrode extension 216. Unless stated otherwise, a stick-out length as used herein refers to the length of the electrical stick-out 216, which is the parameter predominantly affecting the electrical response of the electrode assembly 200. During operation of the electrode assembly 200, the tip portion 208 is positioned adjacent to the workpiece 202 and the distance between the contact tip 210 and the workpiece 202 is referred to as the contact tip to work distance (CTWD) 220.

The electrical stick-out 216 of the electrode wire 206 is preheated by Joule heating. If the electrical electrode extension 216 is not sufficiently long, the electrode wire 206 may not be sufficiently preheated. On the other hand, an increase of the length of the electrical stick-out 216 increases the electrical resistance of the circuit, which in turn increases the heating and hence the temperature of the tip 208 of the electrode 206, leading to increased melting and deposition rate. The length of the electrical stick-out 216 in turn controls the dimensions of the weld bead since the length of the filler wire extension affects the burn-off rate. Further, electrical electrode extension 216 exerts an influence on penetration through its effect on the welding current. As the length of the electrical electrode extension 216 is increased, the preheating of and the voltage drop across the electrode wire 206 increases. The greater voltage drop can result in the bead shape being more convex, which can be overcome by increasing the input voltage by 2-5 volts. The length of the electrical stick-out 216 distance can be approximately 3-10 times a diameter of the electrode 206 depending on the type of steel being welded, for traditional steel welding processes.

FIG. 3A depicts an electrode assembly 300A positioned over a workpiece 302 having a groove 303. In the illustrated configuration, the stick-out portion 316A of the electrode 306A extends a conventional distance beyond the contact tip 310A (e.g., 3 to 12 times the diameter of the electrode). The electrode assembly 300A is positioned such that the head portion 304A is positioned over the groove 303 and the tip 308A of the electrode 308A is within the groove 303. More specifically, the head portion 304A is positioned such that the tip 308A is adjacent to the bottom of the groove 303 without the head portion 304A contacting the workpiece 302. In the illustrated embodiment, the tip 308A is positioned within the groove such that the CTWD 320A is about 25 mm. Positioning the tip 308A closely adjacent to the bottom of the groove 303 allows for better and more consistent arcing between the tip 308A and the workpiece 302, thereby resulting in a more consistent deposition of filler metal into the groove 303 and improved weld quality and efficiency.

To further improve upon submerged arc welding (SAW) technology, a long stick-out (LSO) or extended stick-out technology developed by Lincoln Electric company may be employed. Long stick-out SAW refers to SAW processes in which the length of the wire that sticks out (“stick-out length”) of the electrode contact tip, or the contact-to-work distance (CTWD), is increased relative to conventional SAW processes, e.g., longer than about 25 mm. As used herein, LSO refers to an electrode configuration in which the electrical stick out exceeds about 10 times a diameter of the electrode 306A. The longer stick-out length allows for a greater length of the electrode to be preheated prior to melting at the electrode tip. The preheating allows for melt-off rate to increase as a result, as it is easier to melt a preheated electrode wire for a given current density. The LSO SAW process can provide significant improvement in productivity and can provide up to 100% increase in submerged arc welding deposition rates over traditional SAW processes. The LSO SAW process can reduce or eliminate arc striking problems by allowing complete tailoring of the arc start characteristics. The LSO SAW can also provide improved control over the input of energy into the weld, lower heat input (less distortion), flux/wire ratio reduction.

FIG. 3B depicts an electrode assembly 300B positioned over the groove 303 in workpiece 302. The electrode assembly 300B employs an LSO technology such that the electrical stick-out 316B extends beyond the contact tip 310B by substantially more than the stick-out 316A extending beyond the contact tip 310A (FIG. 3A). For example, in some embodiments, the stick-out 316B can have a length between 10 and 40 times the diameter of the electrode 308B. In some embodiments, the stick-out 316B can have a length that is more than 40 times the diameter of the electrode 308B. The increased length of the stick-out portions 316B allows for a greater length of the electrode 306B to be preheated prior to melting at the electrode trip, thereby allowing for increased melt-off and deposition rates, as explained above.

The increased length of the stick-out portions in LSO SAW systems also allows for the LSO systems to be used to easily fill grooves that conventional SAW systems are either incapable of filling or can only fill using extremely precise arrangements and high operator skill. Specifically, while conventional SAW systems can be used with wide and/or short grooves, conventional SAW systems typically cannot be easily used with deeper and/or narrower grooves. FIGS. 4A and 4B depict electrode assemblies 400A, 400B positioned over a workpiece 402, where the electrode assembly 400A is generally similar to the assembly 300A shown above in connection with FIG. 3A and electrode assembly 400B is generally similar to the assembly 300B shown in above in connection with FIG. 3B. The workpiece 402 has a groove 403 which is substantially deeper and narrower than the groove 303 shown in above in FIGS. 3A and 3B. Accordingly, when the assemblies 400A and 400B are placed over the groove 403, the head portions 404A, 404B are positioned further from the bottom of the groove, resulting in the CTWD 420 being substantially longer than 25 mm. For example, in some embodiments, the CTWD or the electrical stick-out can be 125 mm or longer. When the electrode assembly 400A is positioned over the workpiece 402 such that the tip 408A is within the groove 403, the size and shape of the head portion 404A prevents it from being positioned further within the groove 403 without contacting and interacting with the workpiece 402. As a result, the tip 408A is spaced excessively far from the bottom of the groove 403, which results in poor arcing between the electrode 406A and the workpiece 402, thereby resulting in a poor filler metal deposition rate and poor weld quality. Accordingly, the conventional stick-out length 416A of the electrode assembly 400A prevents the electrode assembly 400A from forming high-quality welds within deep and/or narrow grooves. In contrast, when the electrode assembly 400B is positioned over the workpiece 402B such that the tip 408B is within the groove 403, the increased stick-out length of the assembly 400B allows for the tip 408B to be adjacent to the bottom of the groove. The reduced distance between the tip 408B and the bottom of the groover 403 results in better arcing between the electrode 406B and the workpiece 402. Accordingly, in addition to improving weld quality and deposition rates due to allowing for additional preheating of the electrode prior to arcing, LSO SAW techniques also allow for the deposition of filler metal into the deeper and narrower grooves than conventional SAW techniques.

According to various embodiments, the LSO SAW electrode assemblies are capable of achieving significantly higher deposition rates compared to conventional SAW electrode assemblies for the same current. During the welding process, current is transferred into the electrode by the contact tip at a specific amperage and voltage. As the current flows through the electrode toward the tip of the electrode, the voltage drops and the electrode heats up. At the tip of the electrode, the current arcs to the workpiece. For LSO SAW assemblies, the increased length of the electrode results in a higher fraction of the total voltage drop occurring within the electrode than in conventional SAW assemblies. In some embodiments, the LSO SAW assemblies can be configured such that the voltage drop between the contact tip and the tip of the consumable electrode is at least 5%, at least 10%, at least 15%, or at least 20% (or is a value in a range defined by any of these values) of a total voltage drop across the total CTWD. In other embodiments, the electrode assembly is configured such that the voltage drop between the contact tip and the tip of the consumable electrode represents at least 1/30 of the total voltage drop across the CTWD, 1/15 of the total voltage drop across the CTWD, 1/10 of the total voltage drop across the CTWD, 1/7 of the total voltage drop across the CTWD, ⅕ of the total voltage drop across the CTWD, or a value in a range defined by any of these values. For example, in a conventional SAW electrode assembly where the total voltage drop along the CTWD is 30V, only about 1V of that total voltage drop may occur within the consumable electrode while the rest (about 29V) may drop across the arc length. In contrast, for an LSO SAW system of the same total voltage drop of 30V, about 4V of may drop occurs across the CTWD while the rest (about 26V) may drop cross the arc length. The increased voltage drop through the longer electrode results in the electrode being heated to a higher temperature than the electrode in a conventional SAW configuration and, as a result, the deposition rate increases.

Experiments have shown that the deposition rate per current for LSO SAW assemblies can exceed 0.05 lbs./hr./A, 0.06 lbs./hr./A, 0.07 lbs./hr./A, 0.08 lbs./hr./A, or a value in range defined by any of these values during welding. FIG. 5 illustrates an experimental comparison of deposition rates versus current for both conventional SAW assemblies and LSO SAW assemblies, where the dashed lines represent the deposition rates for conventional SAW assemblies and the solid lines represent the deposition rates for the LSO SAW assemblies. In this experiment, the CTWD for the conventional SAW assembly was 1.25″, the CTWD for the LSO SAW assembly was 5″, and the diameter of the electrode was 5/32″. Three different power delivery methods were used: positive constant DC power, balanced square wave AC power, and 25% balanced square wave AC power. For the LSO SAW assemblies, a deposition rate exceeding 35 lbs./hr. can be achieved with current less than about 900 A, 850 A, 800 A, 750 A, 700 A, or in a range defined by any of these values, e.g., at about 700 A-750 A. For conventional SAW electrode assemblies, however, similar deposition rates are only projected to be achieved at a current exceeding about 900 A. Advantageously, the improvement in deposition rate over conventional SAW electrodes increases at higher current, as Joule heating (FR) varies as a square of current. That is, the relative improvement in deposition rate is projected to increase with increasing current.

In LSO SAW systems, the consumable electrode (e.g., electrodes 306B, 406B) extends beyond the end of the head portion (e.g., head portions 304B, 404B) such that the arcing tip (e.g., tips 308B, 408B) is visible. As previously discussed, the portion of the electrode that extends beyond the contact tip portion is referred to as the electrical stick-out. In some embodiments, the electrical stick-out is measured based on the diameter of the electrode. The length of the electrical stick-out in SAW can depend on the type of steel being welded, e.g., whether the steel being welded is a low alloy steel containing less than about 8 wt. % of non-iron elements or a high alloy steel containing greater than about 8 wt. % of non-iron elements. In conventional SAW for welding low and mild steel, the electrical stick-out length can be approximately 7-10 times the diameter of the electrode. In conventional SAW for welding high alloy steel, the electrical stick-out length can be approximately 3-5 times the diameter of the electrode. For example, in embodiments where the diameter of the electrode is 5/32″, the visible stick-out length can be approximately 1-1.5 inches. In contrast, in LSO SAW according to various embodiments, a stick out-to-diameter ratio, or a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, and a diameter of the electrode exceeds 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or has a value in a range defined by any of these values. For example, these ratios can be obtained by electrical stick-out distance exceeding 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, 150 mm, 155 mm, 160 mm, 165 mm or a value in a range defined by any of these values, and a diameter of the electrode having any value between 2.5 mm and 5.0 mm. For instance, for an electrical stick-out length of 155 mm and an electrode diameter of 3.2 mm, the stick out-to-diameter ratio is about 48, whereas for an electrical stick-out length of 125 mm and an electrode diameter of 4.0 mm, the stick-out-to-diameter ratio is about 31.

While increased stick-out length can advantageously provide certain advantages, such as higher deposition rate, various problems can arise for stick-out lengths exceeding, e.g., 25 mm, when conventional electrode assemblies are used. For example, the heated wire can move out of alignment and wander in the welding groove as the stick-out distance increases. This can pose a problem especially in welding deep and narrow grooves that may be used to minimize time and cost of joining thick sections, as LSO welding electrode assemblies can be too bulky to reach the bottom of the groove. To address this and other challenges, some electrode assemblies include an extension portion that serves as an insulated guide for the electrode. The extension portion provides, among other things, electrical and thermal insulation as well as mechanical rigidity to the heated electrode. However, some extensions may not be suitable for some applications, e.g., for filling narrow and deep grooves such as a triangular or U-shaped groove having a depth exceeding 4 inches and having an angle of an apex that is 16 degrees or less. Some designs of the electrode assemblies that include extension portions may be insufficient with respect to one or more of: optimized vertical and lateral dimensions, thermal and electrical insulation, arc instability caused by magnetic materials and compact flux delivery. In contrast various embodiments of the electrode assembly for submerged arc welding described herein address these and other needs.

Long Stick-Out Electrode Assembly with Covered Insulating Extension Portion

Disclosed herein are various electrode assemblies for improved LSO SAW and method of manufacturing and using the same. FIGS. 6A and 6B depict an example electrode assembly 600 configured for long stick-out submerged arc welding, according to various embodiments. The electrode assembly 600 according to various embodiments comprises a head portion 602, an extension portion 604, and a bracket 612. The head portion 602 and extension portion 604 are arranged serially and configured to feed a consumable electrode 606 therethrough. The bracket 612 is fixedly attached to and electrically insulated from the head portion 602 and the extension portion 604 and is configured to securely hold the extension portion 604 such that the extension portion 604 remains aligned with the head portion 602. The electrode 606 includes a tip configured to be positioned adjacent to a workpiece during the welding process. The head portion 602 includes a contact tip 610 that is in electrical contact with the electrode 606 and is configured to provide power to the electrode 606 during welding. The consumable electrode 606 is fed through the head portion 602 with a wire guide and exits at the contact tip 610. The consumable electrode 606 is subsequently fed through the extension portion 604, which is elongated in a wire feed direction. During SAW, the head portion 602 is disposed to be distal to the tip 608 of the electrode and the extension portion 604 is disposed to be proximal to the tip 608.

In the illustrated example, the serially arranged head portion 602 and extension portion 604 are arranged serially and do not have vertically overlapping portions. While in the illustrated configuration the head portion 602 and the extension portion 604 are physically separated and exposes the consumable electrode 606 therebetween, embodiments are not so limited. In other arrangements, the contact tip portion and the extension portion may contact each other. It will be appreciated that, in the illustrated embodiment, because of the serial arrangement of the head portion 602 and the extension portion 604, the contact tip 610 and the extension portion 604 are also serially arranged, such that no portion of the extension portion 604 overlaps the contact tip 610. Further, the outer surface of the extension portion 604 forms the outermost surface of the electrode assembly 600 adjacent the arcing tip of the exposed consumable electrode 606.

In some embodiments, the electrode assembly 600 also includes a flux delivery system 614. The flux delivery system 614 is configured to deposit flux onto the workpiece during the SAW process. Advantageously, the flux delivery system 614 is configured such that the flux delivery system 614 does not limit the dimensions of a groove of a workpiece the extension portion 604 is capable of being inserted into. In the illustrated embodiment, the flux delivery system 614 is fixedly attached to the extension portion 604 with the bracket 612. In other embodiments, however, the flux delivery system 614 can be fixedly attached to the extension portion 604 in some other way. In still other embodiments, the flux delivery system 614 may not be fixedly attached to the extension portion 604. Instead, in some embodiments, the flux delivery system 614 may be fixedly attached to some other portion of the electrode assembly 600 or may not be attached to any portion of the electrode assembly 600. Additionally, because the electrode assembly 600 is configured for SAW, embodiments of the electrode assembly 600 are configured to be used in SAW systems without the use of a shielding gas.

The extension portion 604 is configured to electrically insulate the consumable electrode 606 from a work piece during welding with an insulating sleeve formed of a solid insulating material, e.g., a ceramic material, surrounding the consumable electrode. In some implementations, the solid insulating material may be a composite or layered insulator, e.g., a composite or layered ceramic. During welding, the consumable welding electrode 606 is preheated in the insulated extension portion 604 by Joule heating, prior to being melted at the arcing tip 608 of the consumable electrode 606. In some embodiments, the electrode assembly 608 is configured to heat the consumable electrode within the extension portion to a temperature up to 600° C., up to 700° C., up to 800° C., up to 900° C., or to a temperature in a range defined by any of these values.

FIG. 6C depicts the electrode assembly 600 positioned within a groove 616 formed in a workpiece 618. In various embodiments, the extension portion 604 is configured to electrically insulate the consumable electrode 606 from the workpiece 618 and has a shape, length and a lateral dimension such that the extension portion 604 is configured to be capable of being inserted into narrow grooves 616 as shown in FIG. 6C. The insulating sleeve formed of a solid insulating material such as a ceramic material surrounding the consumable electrode 606 inside the extension portion 604 allows the lateral dimension of the extension portion 604 to be significantly reduced without increasing the likelihood of shorting the electrode and the workpiece. For example, in some embodiments, while the contact tip 610 can have a width up to 30 mm (or about 1.18 inches), the extension portion 604 can have a width of about 16 mm (or about 0.79 inches). Additionally, in some embodiments, the extension portion can have a length of 110 mm (or about 4.33 inches). In these embodiments, the head portion 602 is spaced sufficiently far apart from the tip 608 of the electrode such that, during welding, the wider head portion 602 can positioned outside of the groove 616 in the workpiece 618 while the narrower extension portion 604 is disposed within the groove. As a result, the narrower extension portion 604 is configured to not contact a sidewall of narrow grooves 616 such as a triangular trench having a depth exceeding 4 inches, 5 inches, 6 inches, 7 inches, or a value in a range defined by any of these values, and having an angle 620 of an apex that is less than 16 degrees, 12 degrees, 10 degrees, 8 degrees, 6 degrees, or a value in a range defined by any of these values, while the tip 608 of the consumable electrode 606 contacts the apex. It will be appreciated that shallower the groove 616, the narrower the apex angle 620 can be. For example, the relationship may follow an example dependence such as that shown in TABLE 1, without limitation. It will be appreciated that the grooves or trenches may not have a triangular shape in cross section. Instead, some grooves may have, e.g., a rectangular or tapered rectangular shape. In these geometries, the “apex” angle 620 or the acceptance angle can be defined by an arctan of a width over depth of the trench.

TABLE 1 Groove Depth Apex Angle >2 in.  <8 deg. >3 in. <10 deg. >4 in. <12 deg.

In various embodiments, the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding while having an outer surface formed of a substantially non-magnetic material surrounding the consumable electrode. FIG. 7A depicts an extension portion 700 and FIG. 7B depicts an exploded view of the extension portion 700. The extension portion 700 has opposing first and second ends 702A, 702B and an opening 704 that extends between the first end 702A and the second end 702B. The extension portion 700 further includes an envelope or nozzle body 706, an insulating sleeve 708 disposed within the nozzle body 706, a c-clamp 710, and a nut 712. As will be discussed in greater detail elsewhere in the application, the insulating sleeve 708 can have a generally cylindrical shape that defines the opening 704. The extension portion 700 is configured to be fixedly attached to the head portion of an electrode assembly (e.g., head portion 602 of electrode assembly 600 shown in FIGS. 6A-6C) such that the first end 702A is proximal to a contact tip within the head portion (e.g., contact tip 610) while the second end 702B is distal to the contact tip. During the SAW process, the extension portion 700 receives a consumable electrode (e.g., electrode 606 in FIGS. 6-6C) from the head portion and the electrode is disposed within the opening 704 such that it extends between the first and second ends 702A, 702B of the extension portion 700. The insulating sleeve 708 is configured to directly surround the consumable electrode without an intervening structure or feature other than air.

In some embodiments, the extension portion 700 is fixedly attached to the head portion with a bracket (e.g., bracket 612 in FIG. 6B) and the c-clamp 710 and nut 712 can be used to fixedly attach the extension portion 700 to the bracket. However, this is merely one possible method of fixedly attaching the extension portion 700 to the head portion and other suitable attachment mechanisms may be used instead. For example, in some embodiments, the extension portion 700 can be fixedly attached to the bracket by welding the nozzle body 706 to the bracket. In these embodiments, the extension portion 700 may not include the c-clamp 710 and nut 712.

FIG. 7C is a perspective view of the envelope or nozzle body 706 and FIG. 7D is a cross-sectional view of the envelope or nozzle body 706 taken along line A-A. The envelope or nozzle body 706 includes first and second ends 714A, 714B and a cavity or opening 716 that extends between the first and second ends 714A, 714B and that is configured to receive and house the insulating sleeve 708 therein. In various embodiments, the envelope or nozzle body 706 can have a generally cylindrical shape having at least a portion that tapers inwards toward the second end 714B. As will be discussed in greater detail elsewhere in the application, the tapered second end 714 advantageously allows multiple electrode assemblies to be positioned more closely adjacent to each other when used in a multi-arc configuration.

According to embodiments, the envelope or nozzle body 706 functions as an outer envelope for the extension portion 700 and can be formed of a non-magnetic material. When the envelope 706 is formed of a magnetic material, it can exert or modify the magnetic field in its vicinity, thereby degrading, modifying or blowing the arc plasma. Furthermore, a magnetic material can become magnetized or demagnetized over time, thereby resulting in a drift of the arc characteristics. To address these and other concerns, in some embodiments, the envelope 706 is formed of a non-magnetic material such as a non-magnetic steel. As described herein, a non-magnetic steel refers to a steel having a low ferrite content and a high austenitic content, e.g., a steel having a ferrite number (FN) less than about 8. For example, the non-magnetic steel can be a high Cr-content steel, such as a stainless steel. Forming the nozzle body 706 out of a non-magnetic material advantageously improves the consistency of the magnetic field around the consumable electrode and reduces arc instability and welding defects. The non-magnetic material also reduces any instability of the welding parameters that may be caused by magnetization of the extension portion 706 over time.

FIG. 7E is a perspective view of the insulating sleeve 708 and FIG. 7F is a cross-sectional view of the insulating sleeve 708 taken along the line B-B. The insulating sleeve 708 includes first and second ends 718A, 718B and has a generally cylindrical shape that forms the opening 704 through which the consumable electrode passes. In representative embodiments, the insulating sleeve 708 is formed of an insulating material that thermally and electrically insulates the electrode as it passes through the extension portion 700. Advantageously, forming the insulating sleeve 708 from an insulating material allows for increased preheating of the consumable electrode during the welding process because the insulating material reduces dissipation of heat generated by the preheating electrode to the surrounding. Instead, the insulating sleeve 708 increases the relative amount of heat that remains trapped within the extension portion 700, thereby increasing the efficiency of preheating of the electrode, which in turn results in higher deposition and melt off rates and higher productivity.

Furthermore, the insulating sleeve 708 allows the extension portion 700 to contact groove sidewalls of the workpiece without risking an electrical short between the electrode and the workpiece. When the electrode is heated to above-described temperatures during welding, the insulating material may lose some of its resistivity. To ensure that voltage drop caused by such contact remains relatively low, the solid insulating material is formed of an insulating material and configured to sustain a voltage difference of at least 5V, 10V, 15V, 20V, 25V or a value in range defined by any of these values, without substantially conducting when an outer surface of the extension portion 700 contacts the workpiece.

In some embodiments, the insulating sleeve 708 is formed from an insulating ceramic material. For example, in some embodiments, the insulating sleeve 708 is formed of alumina (Al2O3) or silicon carbide (SiC). In other embodiments, however, other insulating materials can be used. For example, in some embodiments, the insulating sleeve 708 comprises silicon nitride, magnesia-stabilized zirconia, yttria-stabilized zirconia, magnesium oxide, or a zirconia-toughened alumina. The ceramic insulating sleeve 708 can be manufactured using various methods such as powder pressing, cold isostatic pressing, hot pressing, injection molding and slip casting. Additionally, in some embodiments, the ceramic insulating sleeve 708 is not machined.

In various embodiments, the extension portion 700 is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the length of the electrical stick-out between the contact tip portion (e.g., contact tip 610 shown in FIGS. 6A-6C) and the tip of the consumable electrode (e.g. electrode 606 shown in FIGS. 6A-6C) is substantially longer than in conventional SAW electrode assemblies. For example, in some embodiments, the extension portion 700 has a suitable length for supporting the electrical stick out length described herein. For example, as described above, the electrical stick out can be 125 mm or longer. Accordingly, the extension portion 700 has a length that can be up to approximately 110 mm. The visible stick-out, which corresponds to the portion of the consumable electrode that extends beyond the extension portion 700, can have a length that is a difference between these two values. With this configuration, the length of the electrical stick-out, which includes the portions of the electrode within the extension portion 700 and the visible stick-out, can be at least as large as the sum of the visible stick-out length and the length of the extension portion 700. Accordingly, during welding, the extension portion 700 can cause the electrical-stick-out to exceed 100 mm, 125 mm, 150 mm, 175 mm, or a length in a range defined by any of these values, e.g., 150-160 mm. For example, in some embodiments, the electrode assemblies can have an electrical stick-out of about 155 mm. Advantageously, the longer electrical stick-out substantially improves the deposition rate for a given current density, due to longer Joule-heated region provided by the extension portion 700.

In addition, the insulating sleeve 708 enables, among other things, the shape and width of the extension portion 700 to be optimized for inserting the extension portion 700 into narrow grooves as described herein. According to various embodiments, the maximum width of the extension portion 700 at upper, untampered portions thereof can be less than 20 mm, 18 mm, 16 mm, 14 mm, 12 mm, or a value in a range defined by any of these values. Additionally, in some embodiments, the extension portion 700 can have a generally cylindrical shape having at least a portion that tapers inward towards the second end 714B such that the width of the extension portion 700 at the second end 714B is less than a maximum width of the extension portion 700. In the illustrated configuration, the extension portion 700 is tapered at a lower portion thereof, while an upper portion of the extension portion 700 is substantially straight. However, embodiments are not so limited and in other configurations, the extension portion 700 can be tapered substantially throughout its entire length. For example, in some embodiments, the extension portion 700 can have a maximum width of 16 mm that tapers to a width of 10.8 mm at the second end 714B. In other embodiments, however, the tapered second end 714B can have a different width. For example, in some embodiments, the width of the extension portion 700 at the second end 714B can be 12 mm, 11 mm, 10 mm, 9 mm, 8 mm, less then 8 mm, or a value in a range defined by any of these values. In some embodiments, the extension portion 700 can taper inwards at the second end 714B at an angle of 2°, 3°, 4°, 5°, 6°, 7°, 8°, more than 8°, or a value in a range defined by any of these values. For illustrative purposes only, roughly one third of the length of the illustrated extension portion 700 is tapered. However, it will be appreciated that any suitable fraction of the length may be tapered, including substantially the entire length, e.g., greater than 20%, 40%, 60% or 80%, 100%, or a value in a range defined by any of these values. It will be further appreciated that the tapered sidewall may not be straight, but the degree of tapering may vary with length. For example, the degree of tapering may vary, e.g., continuously or discontinuously, throughout the tapered portion. As configured, the extension portion 700 can be configured to not touch the sidewalls of a narrow groove such as a generally triangular trench as described elsewhere in the application. Any portion of the tapered portion can be configured such that tangents of the exterior sidewalls form a triangle or a cone having an angle of an apex that is less than 16 degrees, 12 degrees, 10 degrees, 8 degrees, 6 degrees, or a value in a range defined by any of these values. Advantageously, the shape and dimensions of the extension portion 700 as described can enable its insertion into narrow grooves without contacting the sidewalls thereof. Additionally, as will be discussed in greater detail elsewhere in the application, the tapered second end 714B advantageously allows multiple electrode assemblies to be positioned more closely adjacent to each other when use din a multi-arc configuration.

Another benefit of the electrode assembly 700 is that flux-to-wire consumption ratio is lower than conventional SAW assemblies because the electrode deposition rate increases while the flux consumption remains constant.

As previously discussed, the insulating sleeve 708 is disposed within the envelope or nozzle body 706. In some embodiments, the insulating sleeve 708 is placed within the nozzle body 706 without an adhesive or other material such that any gaps that may exist between the inner surfaces of the nozzle body 706 and the outer surfaces of the insulating sleeve 708 are filled with air and the insulating sleeve 708 can move or rotate relative to the envelope or nozzle body 706. In other embodiments, however, the insulating sleeve 708 may be securely attached to the nozzle body 706 with an intervening material. For example, in some embodiments, the insulating sleeve 608 is disposed within the nozzle body 706 with a suitable sealant or adhesive. In these embodiments, the suitable sealant may be disposed between the nozzle body 606 and the insulating sleeve 708 such that the sealant fills any gap that may exist between the inner surfaces of the nozzle body 706 and the outer surfaces of the insulating sleeve such that the insulating nozzle 708 is immobilized with respect to the nozzle body 706. In these embodiments, the suitable sealant may be a relatively soft material and may serve as a shock absorbing layer between the insulating sleeve 708 and the nozzle body 706 such that cracking of the insulating sleeve 708 under mechanical or thermal stress is suppressed or prevented. In other embodiments, a different material can be used to securely attach the insulating sleeve 708 within the nozzle body 706. For example, in some embodiments, the insulating sleeve 708 and the envelope or nozzle body 706 may be attached using a brazed metallic joint. In other embodiments, the insulating sleeve 708 and the envelope or nozzle body 706 may be attached using a non-metallic sealant or adhesive such as a polymeric adhesive material or epoxy.

FIG. 8 is a top-down cross-sectional view of an extension portion 800. The extension portion 800 includes an opening 802 through which a consumable electrode is configured to slidingly pass through, an envelope or nozzle body 804, and an insulating sleeve 806 disposed within the envelope or nozzle body 804. In the illustrated embodiment, the insulating sleeve 806 is attached to the envelope 804 using a sealant layer 808. The sealant layer 808 is formed from a suitable sealant that may be a relatively soft material and may serve as a shock absorbing layer between the insulating sleeve 806 and the envelope or nozzle body 804 such that cracking of the insulating sleeve 806 under mechanical or thermal stress is suppressed or prevented. Furthermore, even when the insulating sleeve 806 cracks, the suitable sealant can effectively prevent loose pieces form coming off and falling on the workpiece. In some implementations, insulating sleeve 806 is brazed into the envelope or nozzle body 804 and the suitable sealant comprises a suitable brazing material. The suitable brazing material has a melting temperature that is substantially lower than a melting temperature of the envelope or nozzle body 804. Without limitation, suitable brazing metals include copper-based alloy, e.g., Cu/Sn alloys. In some other implementations the suitable sealant comprises a suitable glass sealant that has a glass working temperature that is substantially lower than a melting temperature of the metallic sheaths. Without limitation, suitable sealants include a doped silica, e.g., a doped aluminosilicate glass or a heavily doped sodium silicate glass. Other sealants may be possible, e.g., high-temperature epoxy that can withstand the outer temperature of the insulating sleeve. Advantageously, securing the insulating sleeve 806 to the envelope 804 using a suitable sealant improves the durability, reliability and lifespan of the extension portion 800.

One additional advantage of utilizing the relatively narrow extension portion as described herein is that it facilitates using multiple electrode assemblies in multi-arc set-ups. When welding large pieces of metal together, it is sometimes desirable to use multiple electrode assemblies at the same time to further increase the filler metal deposition rate. During multi-arc welding, the tips of multiple electrodes should be positioned closely adjacent to each other such that each of the electrode tips is disposed within the same weld pool. However, it is often difficult to use conventional SAW electrode assemblies in a multi-arc set-up. This is because the large diameter of the head portions (e.g., head portions 204 (FIG. 2), 304A (FIG. 3A), 304B (FIG. 3B)) of conventional electrode assemblies makes it difficult for multiple electrode assemblies to be placed sufficiently close to each other to facilitate multi-arc welding. Additionally, the short length of the electrode stick-out portions (e.g., stick-out portions 316A, 416A) used in conventional SAW assemblies may require that the welding torches be arranged at a high angle with respect to each other to allow for the arcing tips of the respective electrodes to be sufficiently close to each other to be positioned within the same weld pool. Accordingly, it is challenging to use conventional SAW electrode assemblies in multi-arc set-ups because the large size of the head portions and the short stick-out length limit the number of electrode assemblies that can be used in multi-arc set-up while also making it difficult to position the torches when trying to weld within a groove. These and other challenges can be mitigated with extension portions according to embodiments having relatively narrow extension portions, as described herein.

FIG. 9A depicts a multi-arc SAW system 900A having first and second electrode assemblies 902A, 902B. The first electrode assembly 902A includes a head portion 904A having a contact tip 906A, an electrode 908A having a tip 910A, an extension portion 912A, and a flux delivery system 914A. Similarly, the electrode assembly 902B includes a head portion 904B having a contact tip 906B, an electrode 908B having a tip 910B, an extension portion 912B, and a flux delivery system 914B. The electrode assemblies 902A, 902B are generally similar to the electrode assembly 600 described above in connection with FIGS. 6A-6C and the extension portions 912A, 912B may be generally similar to the extension portions 700 and 800 described above in connection with FIGS. 7A-7F and FIG. 8. As previously discussed, while the contact tips 906A, 906B can have a width up to 30 mm (or about 1.18 inches), the extension portions 912A, 912B can have a width of about 16 mm (or about 0.79 inches) and a length of about 110 mm (or about 4.33 inches), which allows for the electrode assemblies 902A, 904A to each have an electrical stick-out greater than 125 mm (or about 4.92 inches).

With this configuration, the first and second electrode assemblies 902A, 902B can be positioned such that a distance 916 between the tips 910A, 910B of the electrodes 908A, 908B is sufficiently small to allow for efficient multi-arc welding. Specifically, the shape, length, and width of the extension portions 912A, 912B as described herein allows for the extension portions 912A, 912B to be simultaneously positioned within narrow and deep grooves such that the tips 910A, 910B are disposed within the same weld pool during the SAW process without the extension portions contacting the sidewalls of the grooves. For example, in some embodiments, the first and second electrode assemblies 902A, 902B can be positioned such that, during welding, the distance 916 between the tips 910A, 910B is 15 mm while the angle 920 between the electrode assemblies 902A, 902B is 20 degrees. However, this is only one example. In other embodiments, the electrode assemblies 902A, 902B can be positioned such that, during multi-arc welding operations, the distance 916 between the tips 910A, 910B is less than 30 mm, 25 mm, 20 mm, 15 mm, or a value in a range defined by any one of these values, and the electrode assemblies 902A, 902B are oriented such that the angle 920 between the electrode assemblies 902A, 902B is less than 40 degrees, 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees, 5 degrees, or a value in a range defined by any one of these values.

FIG. 9B depicts another multi-arc SAW system 900B having three electrode assemblies 902A, 902B, and 902C, where each of the electrode assemblies 902A, 902B, and 902C is configured as described above in connection with FIG. 9A. The size, shape, and width of the extension portions 912A, 912B, 912C for the electrode assemblies 902A, 902B, 902C as described herein allows for extension portions 912A, 912B, 912C to be simultaneously positioned with narrow and deep grooves such that the electrode tips 910A, 910B, 910C are all disposed within the same weld pool during the SAW process without the extension portions contacting the sidewalls of the groove. For example, in the illustrated embodiment, the electrode assemblies 902A, 902B, 902C are positioned such that the distance 916 between the first and second tips 910A, 910B is 26 mm, the distance 918 between the second and third tips 910B, 910C are spaced apart from each other by 15 mm, the angle 920 between the first and second electrode assemblies 902A, 902B is 5 degrees, and the angle 922 between the second and third electrode assemblies 902B, 902C is 20 degrees. However, this is only an example. In other embodiments, the electrode assemblies 902A, 902B, 902C can be positioned such that, during multi-arc welding operations, the distances 916, 918 between adjacent tips 910A, 910B, 910C is less than 30 mm, 25 mm, 20 mm, 15 mm, or a value in a range defined by any one of these values, and electrode assemblies 902A, 902B, 902C are oriented such that the angles 920, 922 between adjacent electrode assemblies 902A, 902B, 902C is less than 40 degrees, 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees, 5 degrees, or a value in a range defined by any one of these values.

Still referring to FIGS. 9A and 9B, according to embodiments, each of the first, second (and third) electrode assemblies 902A, 902B (and 902C) is configured such that each of the multiple electrodes independently receives power from a dedicated power supply (e.g., power supply 108 shown in FIG. 1). With this arrangement, each of the electrode assemblies can receive an independently controlled power, which allows for more consistent and efficient deposition of filler metal. Additionally, the current provided to each electrode assemblies can be varied for each electrode assembly such that individual electrode assemblies can receive different currents. In other embodiments, however, each of the electrode assemblies used in a multi-arc set-up can be coupled together in parallel such that each of the electrode assemblies shares the same current.

ADDITIONAL EXAMPLES

1. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating material surrounding the consumable electrode.

2. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the extension portion is configured to capable of not contacting a sidewall of a triangular trench having a depth exceeding 4 inches and having an angle of an apex that is less than 16 degrees while the tip of the consumable electrode contacts the apex.

3. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding while having an outer surface formed of a substantially non-magnetic material surrounding the consumable electrode.

4. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that a contact-to-work distance (CTWD) between the head portion and the tip of the consumable electrode during welding exceeds 125 mm.

5. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding; and
    • a flux delivery system fixedly attached to the extension portion and configured such that the flux delivery system does not limit dimensions of a groove of a workpiece the extension portion is capable of being inserted into.

6. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to achieve a deposition rate per current exceeding 0.05 lbs./hr./A during welding.

7. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to achieve a deposition rate exceeding 35 lbs./hr. at a current less than 900 A during welding.

8. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to drop at least 5% of a total voltage drop cross a contact-to-work distance (CTWD) between the head portion and the tip of the consumable electrode.

9. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to drop at fraction exceeding 2V of a total voltage drop cross a contact-to-work distance (CTWD) between the head portion and the tip of the consumable electrode.

10. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature up to 800° C.

11. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating material, wherein the solid insulating material has sufficient resistance such that it is configured to sustain a voltage difference of at least 5V without substantially conducting when an outer surface of the extension portion contacts the work piece.

12. An electrode assembly for submerged arc welding, comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion comprises an insulating tip portion formed of a solid insulating material configured to electrically insulate the consumable electrode from a work piece during welding by surrounding the consumable electrode.

13. The electrode assembly according to any of the above examples, wherein the solid insulating material comprises a ceramic material.

14. The electrode assembly according to any of the above examples, wherein the solid insulating material comprises an insulating sleeve configured to pass the consumable electrode therethrough.

15. The electrode assembly of any one of the above examples, wherein the extension portion is formed of a material selected from the group consisting of silicon nitride, magnesia-stabilized zirconia, yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina or a zirconia-toughened alumina.

16. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the extension portion is configured to be capable of not contacting a sidewall of a triangular trench having a depth exceeding 4 inches and having an angle of an apex that is less than 16 degrees while the tip of the consumable electrode contacts the apex.

17. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding while having an outer surface formed of a substantially non-magnetic material surrounding the consumable electrode.

18. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that a contact tip-to-work distance (CTWD) between the contact tip portion and the tip of the consumable electrode during welding exceeds 125 mm.

19. The electrode assembly of any one of the above examples, further comprising a flux delivery system fixedly attached to the extension portion and configured such that the flux delivery system does not limit dimensions of a groove of a workpiece the extension portion is capable of being inserted into.

20. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to achieve a deposition rate per current exceeding 0.05 lbs./hr./A during welding.

21. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to achieve a deposition rate exceeding 35 lbs./hr. at a current less than 900 A during welding.

22. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the consumable electrode drops at least 5% of a total voltage drop cross a contact-to-work distance (CTWD) between the contact tip portion and the tip of the consumable electrode.

23. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that a stick-out portion of the consumable electrode drops at least 2V of a total voltage drop cross a contact-to-work distance (CTWD) between the contact tip portion and the tip of the consumable electrode.

24. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece and has a shape, length and a lateral dimension such that the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature up to 800° C.

25. The electrode assembly of any one of the above examples, wherein the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating sleeve, wherein the solid insulating sleeve has sufficient resistance such that it is configured to sustain a voltage difference of at least 5V without substantially conducting when an outer surface of the extension portion contacts the work piece.

26. An electrode assembly for submerged arc welding (SAW), comprising:

    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
    • wherein the extension portion is elongated in a wire feed direction and configured to electrically insulate the consumable electrode from a work piece during welding with an insulating sleeve surrounding the consumable electrode, and
    • wherein the electrode assembly is configured such that, during welding with the consumable electrode inserted therethrough, a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, and a diameter of the electrode exceeds 30.

27. The electrode assembly of example 26, wherein the extension portion has an outer surface formed of a substantially non-magnetic material surrounding the insulating sleeve.

28. The electrode assembly of example 27, wherein the insulating sleeve is formed of a ceramic material that is enveloped by a substantially non-magnetic steel-based envelope forming the outer surface of the extension portion.

29. The electrode assembly of example 28, wherein the insulating sleeve and the non-magnetic steel-based envelope are held together by an adhesive layer.

30. The electrode assembly of example 29, wherein the adhesive layer comprises a brazed joint comprising a metallic filler material.

31. The electrode assembly of example 26, wherein the extension portion has a length greater than 100 mm.

32. The electrode assembly of example 31 wherein the electrode assembly is configured for the electrical stick-out distance exceeding 125 mm.

33. The electrode assembly of example 32, wherein the electrode assembly is configured for the diameter of the electrode exceeding 3 mm.

34. The electrode assembly of example 32, wherein the extension portion has an elongated shape such that, when fully inserted into a triangular trench having a depth exceeding 4 inches and having an angle of an apex that is less than 16 degrees such that the tip of the consumable electrode contacts the apex of the triangular trench, no part of the extension portion contacts a sidewall of the triangular trench.

35. The electrode assembly of example 32, wherein the electrode assembly is configured to achieve a deposition rate per current exceeding 0.05 lbs./hr./A during welding.

36. The electrode assembly of example 32, wherein the electrode assembly is configured to achieve a deposition rate exceeding 35 lbs./hr. at a current less than 900 A during welding.

37. The electrode assembly of example 32, wherein the electrode assembly is configured to drop at least 5% of a total voltage drop across a distance between the head portion and the arcing tip of the consumable electrode.

38. The electrode assembly of example 32, wherein the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature up to 800° C.

39. The electrode assembly of example 26, wherein the insulating sleeve has sufficient resistance such that it is configured to sustain a voltage difference of at least 5V without substantially conducting when an outer surface of the extension portion contacts the work piece.

40. The electrode assembly of example 39 wherein the insulating sleeve is formed of a ceramic material selected from the group consisting of silicon nitride, magnesia-stabilized zirconia, yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina, or a zirconia-toughened alumina.

41. The electrode assembly of example 26, further comprising:

    • a flux delivery system fixedly attached to the extension portion and configured such that the flux delivery system does not limit a lower limit of a width of a groove of a workpiece the extension portion is capable of being inserted into.

42. An electrode assembly for submerged arc welding, comprising:

    • a head portion; and
    • an extension portion arranged serially with the head portion in a wire feed direction, wherein the head portion and the extension portion are configured to feed a consumable electrode therethrough, wherein the extension portion is configured to be disposed closer to an arcing tip of the consumable electrode relative to the head portion and comprises:
      • an envelope formed of a nonmagnetic material; and
      • an insulating sleeve disposed within the envelope and comprising a solid insulating material configured to surround the consumable electrode.

43. The electrode assembly of example 42 wherein:

    • the extension portion comprises opposing first and second ends separated in the wire feed direction,
    • the head portion comprises a contact tip portion configured to apply a voltage and pass current to the consumable electrode and configured to be proximal to the first end of the extension portion and distal to the second end of the extension portion,
    • when the consumable electrode is fed through the electrode assembly, an arcing tip of the consumable electrode is configured to be proximal to the second end of the extension portion and distal to the first end of the extension portion, and
    • the extension portion is disposed between the arcing tip and the contact tip portion.

44. The electrode assembly of example 43 wherein the electrode assembly is configured for an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, exceeding 125 mm.

45. The electrode assembly of example 44, wherein the electrode assembly configured such that a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, and a diameter of the electrode exceeds 30.

46. The electrode assembly of example 42 wherein the solid insulating material comprises a ceramic material.

47. The electrode assembly of example 42 wherein the insulating sleeve is fixedly attached to the envelope by an adhesive layer.

48. The electrode assembly of example 47 wherein adhesive layer comprises a brazed metallic joint.

49. An extension portion configured for a submerged arc welding electrode assembly, the extension portion comprising:

    • an envelope formed of a nonmagnetic material; and
    • an insulating sleeve disposed within the envelope and comprising a solid insulating material configured to surround a consumable electrode,
    • wherein the extension portion is configured to be arranged serially with a head portion of the electrode assembly and to receive a consumable electrode from the head portion.

50. The extension portion of example 49, wherein the extension portion has a length greater than 100 mm.

51. The extension portion of example 49, wherein the extension portion is configured for a diameter of the consumable electrode exceeding 3 mm.

52. The extension portion of example 51, wherein the extension portion is configured such that during welding with the consumable electrode inserted therethrough, a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and an arcing tip of the consumable electrode, and the diameter of the electrode exceeds 30.

53. The extension portion of example 49, wherein the insulating sleeve is formed of a ceramic material.

54. The extension portion of example 49, wherein the envelope is formed of a substantially non-magnetic steel-based material.

55. The extension portion of example 54, wherein the envelope is formed of a stainless steel.

56. The extension portion of example 49, wherein the insulating sleeve and the envelope are held together by an adhesive layer.

57. The extension portion of example 56, wherein the adhesive layer comprises a brazed joint comprising a metallic filler material.

58. A method of welding a workpiece, comprising:

    • providing a submerged arc welding electrode assembly, the electrode assembly comprising:
    • a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein:
      • the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode, and
      • the extension portion is configured to electrically insulate the consumable electrode from a work piece during welding with a solid insulating material surrounding the consumable electrode;
    • positioning the electrode assembly over the workpiece such that the arcing tip is adjacent to the workpiece;
    • adjusting the electrode assembly such that a distance between the head portion and the arcing tip of the consumable electrode during welding exceeds 125 mm; and
    • providing a current to the electrode assembly.

59. The method of example 58 wherein the extension portion has a length greater than 100 mm

60. The method of example 58 wherein:

    • the workpiece comprises a triangular trench having a depth exceeding 4 inches and having an angle of an apex that is less than 16 degrees,
    • positioning the electrode assembly over the workpiece comprises positioning the electrode assembly such that the extension portion is within the groove and the arcing tip contacts the apex.

61. The method of example 60, further comprising:

    • moving the electrode assembly through the groove without the extension portion contacting a sidewall of the triangular trench while the arcing tip contacts the apex.

62. The method of example 58 wherein the electrode assembly is configured to achieve a deposition rate per current exceeding 0.05 lbs./hr./A.

63. The method of example 58 wherein the electrode assembly is configured to achieve a deposition rate exceeding 35 lbs./hr. at a current less than 900 A.

64. The method of example 58 wherein the electrode assembly is configured to drop at least 5% of a total voltage drop across a distance between the head portion and the arcing tip of the consumable electrode.

65. The method of example 58 wherein the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature up to 800° C. during welding.

66. A multi-arc welding system for submerged arc welding within a groove on a workpiece, wherein the groove has a depth exceeding 4 inches and an angle of an apex that is less than 16 degrees, the system comprising:

    • a first electrode assembly, wherein the first electrode assembly comprises:
      • a first head portion; and
      • a first extension portion arranged serially with the first head portion, wherein the first head portion and the first extension portion are configured to feed a first consumable electrode therethrough, wherein the first extension portion comprises a first nozzle body formed from a nonmagnetic material and a first insulating sleeve disposed within the nozzle body and comprising a solid insulating material configured to surround the first consumable electrode; and a second electrode assembly, wherein the second electrode assembly comprises:
      • a second head portion; and
      • a second extension portion arranged serially with the second head portion, wherein the second head portion and the second extension portion are configured to feed a second consumable electrode therethrough, wherein the second extension portion comprises a second nozzle body formed from the nonmagnetic material and a second insulating sleeve disposed within the second nozzle body, wherein the second insulating sleeve comprises the solid insulating material that is configured to surround the second consumable electrode,
    • wherein, during welding, the first and second electrode assemblies are configured to be positioned within the groove such that tips of the first and second consumable electrodes are closely adjacent to the apex of the groove and closely adjacent to each other without the first and second extension portions contacting a sidewall of the groove.

67. The system of example 66 wherein, during welding, the first and second electrode assemblies are configured to be positioned within the groove such that a distance between the tips of the first and second consumable electrodes is less than 30 mm and an angle between the first and second electrode assemblies is less than 40 degrees.

68. The system of example 66, further comprising:

    • a third electrode assembly, comprising:
      • a third head portion; and
      • a third extension portion arranged serially with the third head portion,
    • wherein the third head portion and the third extension portion are configured to feed a third consumable electrode therethrough,
    • wherein the third extension portion comprises a third nozzle body formed from the nonmagnetic material and a third insulating sleeve disposed within the second nozzle body,
    • wherein the third insulating sleeve comprises the solid insulating material that is configured to surround the second consumable electrode, and
    • wherein, during welding, third electrode assembly is configured to be positioned within the groove such that a tip of the third consumable electrode is closely adjacent to the tips of the first and second consumable electrodes without the third extension portion contacting the sidewall of the groove.

69. The system of example 66, wherein:

    • the first electrode assembly comprises a first flux delivery system securely attached to the first head portion,
    • the second electrode assembly comprises a second flux delivery system securely attached to the second head portion,
    • the first and second flux delivery systems are configured to deposit flux into the groove, and
    • during welding, the first and second flux delivery systems do not contact the sidewall of the groove.

70. The system of example 66 wherein the first and second extension portions each have a length greater than 100 mm.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” “include,” “including” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number, respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

Moreover, conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or whether these features, elements and/or states are included or are to be performed in any particular embodiment.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functionalities with different components and/or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide further embodiments. The various features and processes described above may be implemented independently of one another, or may be combined in various ways. All possible combinations and subcombinations of features of this disclosure are intended to fall within the scope of this disclosure.

Claims

1. An electrode assembly for submerged arc welding (SAW), comprising:

a head portion and an extension portion arranged serially and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed to be distal to an arcing tip of the consumable electrode and the extension portion is disposed to be proximal to the arcing tip of the consumable electrode,
wherein the extension portion is elongated in a wire feed direction and configured to electrically insulate the consumable electrode from a work piece during welding with an insulating sleeve surrounding the consumable electrode, and
wherein the electrode assembly is configured such that, during welding with the consumable electrode inserted therethrough, a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, and a diameter of the consumable electrode exceeds 30.

2. The electrode assembly of claim 1, wherein the extension portion has an outer surface formed of a substantially non-magnetic material surrounding the insulating sleeve.

3. The electrode assembly of claim 2, wherein the insulating sleeve is formed of a ceramic material that is enveloped by a substantially non-magnetic steel-based envelope forming the outer surface of the extension portion.

4. The electrode assembly of claim 3, wherein the insulating sleeve and the non-magnetic steel-based envelope are held together by an adhesive layer.

5. (canceled)

6. The electrode assembly of claim 1, wherein the extension portion has a length greater than 100 mm and wherein the electrode assembly is configured for the electrical stick-out distance exceeding 125 mm.

7. (canceled)

8. (canceled)

9. The electrode assembly of claim 6, wherein the extension portion has an elongated shape such that, when fully inserted into a triangular trench having a depth exceeding 4 inches and having an angle of an apex that is less than 16 degrees such that the tip of the consumable electrode contacts the apex of the triangular trench, no part of the extension portion contacts a sidewall of the triangular trench.

10. The electrode assembly of claim 6, wherein the electrode assembly is configured to achieve a deposition rate per current exceeding 0.05 lbs./hr./A during welding.

11. The electrode assembly of claim 6, wherein the electrode assembly is configured to achieve a deposition rate exceeding 35 lbs./hr. at a current less than 900 A during welding.

12. The electrode assembly of claim 6, wherein the electrode assembly is configured to drop at least 5% of a total voltage drop across a distance between the head portion and the arcing tip of the consumable electrode.

13. The electrode assembly of claim 6, wherein the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature up to 800° C.

14. (canceled)

15. The electrode assembly of claim 1 wherein the insulating sleeve is formed of a ceramic material selected from the group consisting of silicon nitride, magnesia-stabilized zirconia, yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina, or a zirconia-toughened alumina.

16. The electrode assembly of claim 1, further comprising:

a flux delivery system fixedly attached to the extension portion and configured such that the flux delivery system does not limit a lower limit of a width of a groove of a workpiece the extension portion is capable of being inserted into.

17. An electrode assembly for submerged arc welding, comprising:

a head portion; and
an extension portion arranged serially with the head portion in a wire feed direction, wherein the head portion and the extension portion are configured to feed a consumable electrode therethrough, wherein the extension portion is configured to be disposed closer to an arcing tip of the consumable electrode relative to the head portion and comprises: an envelope formed of a nonmagnetic material; and an insulating sleeve disposed within the envelope and comprising a solid insulating material configured to surround the consumable electrode.

18. The electrode assembly of claim 17 wherein:

the extension portion comprises opposing first and second ends separated in the wire feed direction,
the head portion comprises a contact tip portion configured to apply a voltage and pass current to the consumable electrode and configured to be proximal to the first end of the extension portion and distal to the second end of the extension portion,
when the consumable electrode is fed through the electrode assembly, an arcing tip of the consumable electrode is configured to be proximal to the second end of the extension portion and distal to the first end of the extension portion, and
the extension portion is disposed between the arcing tip and the contact tip portion.

19. The electrode assembly of claim 18 wherein the electrode assembly is configured for an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, exceeding 125 mm.

20. The electrode assembly of claim 19, wherein the electrode assembly configured such that a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and the arcing tip of the consumable electrode, and a diameter of the electrode exceeds 30.

21. The electrode assembly of claim 17, wherein the solid insulating material comprises a ceramic material.

22. The electrode assembly of claim 17, wherein the insulating sleeve is fixedly attached to the envelope by an adhesive layer that comprises a brazed metallic joint.

23. (canceled)

24. An extension portion configured for a submerged arc welding electrode assembly, the extension portion comprising:

an envelope formed of a nonmagnetic material; and
an insulating sleeve disposed within the envelope and comprising a solid insulating material configured to surround a consumable electrode,
wherein the extension portion is configured to be arranged serially with a head portion of the electrode assembly and to receive the consumable electrode from the head portion.

25. The extension portion of claim 24, wherein the extension portion has a length greater than 100 mm.

26. The extension portion of claim 24, wherein the extension portion is configured for a diameter of the consumable electrode exceeding 3 mm.

27. The extension portion of claim 26, wherein the extension portion is configured such that during welding with the consumable electrode inserted therethrough, a ratio between an electrical stick-out distance, measured between a contact tip portion disposed at an end of the head portion and an arcing tip of the consumable electrode, and the diameter of the electrode exceeds 30.

28. The extension portion of claim 24, wherein the insulating sleeve is formed of a ceramic material.

29. The extension portion of claim 24, wherein the envelope is formed of a substantially non-magnetic steel-based material.

30. (canceled)

31. The extension portion of claim 24, wherein the insulating sleeve and the envelope are held together by an adhesive layer.

32. (canceled)

Patent History
Publication number: 20230158596
Type: Application
Filed: Nov 18, 2022
Publication Date: May 25, 2023
Inventors: Romain Ravet (Parthenay), Yann Levillain (Cauverville-en-Roumois), Yann Rivet (Grand-Couronne), Laurent Longinotti (Les Ageux), Loic Verwaerde (Saint Aubin Epinay), Telmo Agostinho (Conflans Sainte Honorine), Dirk Haupt (Hofheim am Taunus), Christoph Vollet (Ebertsheim), Jerome Cantet (Neuvy-Bouin), Michel Jany (Mont Saint Aignan), Christopher Thume (Iserlohn), Frank Bolte (Essen), Roland Pollmann (Velbert), Bryan M. O'Neil (Double Oak, TX)
Application Number: 18/056,927
Classifications
International Classification: B23K 9/12 (20060101); B23K 9/10 (20060101); B23K 9/18 (20060101);