Abstract: A method of manufacturing a waterproof strapped accessory and a waterproof strapped accessory formed according to the disclosed method are provided. Using a thermal laser cutter, a raw thermal polyurethane-coated nylon webbing material is cut, obtaining a desired shape of a strapped accessory. Holes may be cut through the strapped accessory using the thermal laser cutter. The thermal laser cutter seals the cut edges of the strapped accessory as well as any hole cut by the thermal laser cutter, rendering all or most edges waterproof. The strapped accessory is then inspected, and any unsealed edges sealed with a thermal rod. The strapped accessory is then cleaned of any residue and allow to cure under predetermined environmental conditions for a predetermined amount of time. Keepers and/or any desired hardware may be affixed to the strapped accessory. Indicia may also be imparted onto the strapped accessory by the thermal laser cutter.

Abstract: A part of a plate member is machined to remove material therefrom so as to obtain an intermediate product having a thickness difference. Then, the intermediate product is bent and both edges thereof are joined to obtain a cylindrical body. Further, a first heat treatment of heating the cylindrical body is performed. Then, through holes penetrating from the outside to the inside of the peripheral wall of the cylindrical body are formed. Pipe parts are joined to the tubular body thus obtained to form a tubular member. This tubular member is subjected to a second heat treatment.

Abstract: A method (100) for processing conductor segments (2) of a winding support (3) of an electric motor, wherein at least two conductor segments (2) are arranged on the winding support (3), wherein the conductor segments (2) protrude out of the end side of the winding support (3) by way of end sections (4).

Abstract: A method for manufacturing a clad steel pipe is provided, wherein the clad steel pipe is manufactured by using a clad steel plate as a raw material. The clad steel plate comprises a base layer (1) and a clad layer (2) roll-bonded with the base layer (1). The method for manufacturing a clad steel pipe comprises the steps of forming, welding, and deburring; both sides of the clad steel plate are bent towards the base layer (1) side of the clad steel plate, then the forming step is carried out, and after the forming step, the opening faces of the resultant pipe blank are all in a form of the clad layer (2). According to the method for manufacturing a clad steel pipe, a clad steel pipe is manufactured by using a clad steel plate as a raw material. Thus, continuance and high efficiency of a high-frequency longitudinal welding pipe unit is fully utilized, subsequent non-continuous processes are not necessary, and the corrosion resistance at the weld of the clad steel pipe is ensured.

Abstract: An apparatus for inspecting and/or measuring a gear wheel workpiece, which comprises: a first workpiece spindle for fastening and rotationally driving the gear wheel workpiece, a rotational drive for rotationally driving the gear wheel workpiece when it is fastened on the first workpiece spindle, measuring means for inspecting and/or measuring the gear wheel workpiece when it is fastened on the first workpiece spindle, wherein the rotational drive is designed to rotationally drive the gear wheel workpiece including the first workpiece spindle during a measurement and/or inspection phase, while the measuring means is used for inspecting and/or measuring the gear wheel workpiece, rotationally drive the gear wheel workpiece including the workpiece spindle during a spinning phase to spin off a liquid.

Abstract: Provided is a method for joining two dissimilar metal plates having different volume resistivity to increase joint strength of the metal plates. The method includes: overlapping a first metal plate including a first metal and a second metal plate including a second metal, the second metal having volume resistivity higher than the first metal and being different from the first metal, and bringing a pair of electrodes into contact with a surface of an overlapped portion of the first metal plate that is overlapped with the second metal plate; and applying current between the electrodes so as to melt the first metal present at a current-flowing region of the overlapped portion due to heat generated by resistance to form an intermetallic compound of the first and the second metals between the first and the second metal plates and join the first and the second metal plates via the intermetallic compound.

Abstract: A method for joining two dissimilar metal plates having different volume resistivity with enhanced joint strength. The method includes overlaying a first metal plate made of first metal and a second metal plate made of second metal with higher volume resistivity and higher melting point in comparison with the first metal, bringing a pair of electrodes into contact with the surface of a portion of the second metal plate overlapping the first metal plate, supplying current between the electrodes so as to resistance-heat the second metal present in a current-flowing region to a temperature lower than the melting point of the second metal and higher than the melting point of the first metal, thereby partially melting the first metal plate with the heat so that an intermetallic compound is generated between the first and second metal plates, and thus joining the first and second metal plates via the intermetallic compound.

Abstract: Manufacturing methods for fabricating nuclear waste canisters used to store spent nuclear fuel assemblies are disclosed to mitigate stress corrosion cracking. The method may generally comprise providing one or more stainless steel sheets used to form a shell of the canister. The shell comprises open butt joints which are welded closed via full shell thickness type welds of preferably narrow profile. The welds and adjoining heat affect zone may then be subjected to mechanical through-thickness compaction, which converts a residual tensile stress field in the shell base material adjoining the weld to a compressive stress field for a full thickness of the shell. The crown of the external exposed portion of the weld is flattened by the compaction and may be coplanar with the exterior surface of the shell. Surface peening may optionally be performed on the welded zone after compaction.

Abstract: A method of making an annular component includes forming sheet feedstock into an annular shape disposed about a central axis; and bonding one portion of the feedstock to another portion of the feedstock using ultrasonic welding, so as to fix the annular shape.

Abstract: The present disclosure generally relates to a system for heating a bulk medium includes two or more electrodes spaced apart from one another and coupled to the bulk medium; and a power control system coupled to the electrodes, the power control system configured to heat the bulk medium by shaping a density of the current along a current path between the electrodes, thereby, producing an effective resistance along the current path in the bulk medium that is greater than the resistance of the bulk medium to a DC current, in which the power control system shapes the density of the current within a depth of the bulk medium by tuning a skin-depth of the current, and in which the power control system shapes the density of the current in a direction across the current path by tuning a proximity effect of the current.

Abstract: An apparatus and method for manufacturing a notched corner board is disclosed. The method includes cutting bent board stock into fixed lengths; forming a slit in or near an end of the corner board; and bending/folding a part of the corner board between the end and the slit to create a notch or flap in the corner board. The apparatus includes one or more cutting tools configured to form a slit in or near a first end of the corner board, a support block configured to support the corner board as the slit is formed, one or more rollers configured to move the corner board towards the cutting tool(s), a frame to which the cutting tool(s), the support block, and the roller(s) are directly or indirectly attached, a motor, and a punch. The motor controls movement of the punch to form the notch in the corner board.

Abstract: A production method provides for punching holes in a metal strip, cold-forming the metal strip to form a guide tube, and joining the lengthwise edges of the metal strip to each other by a seam or teeth so as to create a uniform material. Subsequently, a piston-like striker is inserted into the guide tube.

Abstract: A method and a device for inductive radiofrequency welding of metal products, include heating by inducing radiofrequency currents with use of at least one induction conductor. The metal products and a welding zone are moved relative to one another, so that edge regions of the metal products to be welded are brought in contact in the welding zone and are welded together to form a weld seam. Metal products with different material thicknesses and/or material properties can be welded together because an induction conductor which heats the edge regions of the metal products is used which includes at least two mutually separable induction conductor components that are assigned to the respective metal product and are adapted thereto, and the edge regions to be welded are heated in a manner that is adjusted separately for the respective metal product.

Abstract: A method for manufacturing an electric resistance steel pipe having a good toughness at a welded portion is provided, the method being capable of stably manufacturing an electric resistance welded steel pipe having a desirable toughness at a welded portion although a steel strip serving as a base material has a dimensional variation. Groove shapes and are applied to edges and of an open pipe, an edge shape monitor continuously captures images of the edges and immediately before electric resistance welding, and the captured images are input to an arithmetic processing unit for image processing.

Abstract: A high-strength thick-walled electric resistance welded steel pipe has excellent low-temperature toughness and excellent HIC resistance and a yield strength of 400 MPa or more. The steel has a chemical composition consisting of C: 0.025% to 0.084%, Si: 0.10% to 0.30%, Mn: 0.70% to 1.80%, controlled amounts of P, S, Al, N, and O, Nb: 0.001% to 0.065%, V: 0.001% to 0.065%, Ti: 0.001% to 0.033%, and Ca: 0.0001% to 0.0035% on a mass percent basis and the remainder being Fe and incidental impurities, and satisfies Pcm of 0.20 or less.

Abstract: A low-yield ratio high-strength electric resistance welded steel pipe has a yield ratio of 80% or less and a TS of 655 MPa or more. A steel material has a composition containing 0.38% to 0.45% C, 0.1% to 0.3% Si, 1.0% to 1.8% Mn, 0.03% or less P, 0.03% or less S, 0.01% to 0.07% sol. Al, and 0.01% or less N on a mass basis.

Abstract: Provided is an electrode support structure in which local heating can be prevented from occurring in a workpiece during the electric heating. The electrode support structure is usable for applying a load to the electrodes used for the electric heating of a metal plate, and comprises at least two members, i.e., a first member to which the electrodes are fixed and a second member which receives the load from the first member or connects the first member to a load means. The support structure in which the two members are joined to each other through an elastic member can uniformly apply the load to the electrodes for electric heating so that the electrodes can uniformly contact with the workpiece, whereby the workpiece can be uniformly heated.

Abstract: An object to be processed 1 is irradiated with laser light L with a standard pulse waveform, so as to form a molten processed region 131, which has a larger size in the thickness direction of the object 1 and is easy to generate a fracture 24 in the thickness direction of the object 1, within a silicon wafer 111, and with laser light L with a retarded pulse waveform, so as to form a molten processed region 132, which has a smaller size in the thickness direction of the object 1 and is hard to generate the fracture 24 in the thickness direction of the object 1, within a silicon wafer 112.

Abstract: Apparatus and methods for assembling solar receiving tubes in the field are described. In one embodiment, a welder is provided having longitudinally adjustable clamps that permit the easy restraining and adjustment of tube position for welding. In another embodiment, a system for moving along the length of a solar collector and sequentially welding tubes is described.

Abstract: A guiding and shaping system for producing welded pipes made from metallic strip material. The guiding and shaping system comprises several pairs of rolls that are disposed one behind another in the direction of travel of the workpiece and are used for increasingly cold-working and bending the edges of the workpiece as the workpiece advances. First pairs of rolls grip the top side and bottom side of the workpiece while pairs of rolls that grip the external faces of the bent edges and form the shape of a pipe are provided in the region where the bent edges form undercuts. The guiding and shaping system further comprises a welding device. The workpiece is supported by floatingly mounted lateral rolls until cooling off following the welding process.

Abstract: A flange (13) for use in direct resistance heating of a glass-carrying vessel (10), such as a finer, is provided. The flange comprises a plurality of electrically-conductive rings which include an innermost ring (140) which is joined to the vessel's exterior wall (12) during use of the flange and an outermost ring (150) which receives electrical current during use of the flange. The innermost ring (140) comprises a high-temperature metal which comprises at least 80% platinum and the outermost ring (150) comprises at least 99.0% nickel. This combination of materials both increases the reliability of the flange and reduces its cost. In certain embodiments, the flange can also include one or more rings (190) composed of a platinum-nickel alloy which has a lower thermal conductivity than platinum or nickel and thus can serve to reduce heat loss through the flange.

Abstract: A squeeze roll stand includes a combination of a fixed portion installed at a joint position of an electric resistance welded pipe manufacturing line, in which squeeze rolls excluding left and right upper rolls are detachably assembled, and a movable portion overlying the fixed portion, inside which left and right upper rolls are detachably assembled, the movable portion being inclined, taking a back surface downstream side as a fulcrum point, toward a same side from an assembling position on the fixed portion to a retreat position to open an upper part of the fixed portion. The movable portion is driven and reciprocated between the assembling position and the retreat position with cylinder type actuators as a drive mechanism. At the retreat position, the movable portion overlies a bead grinding device arranged on the back surface downstream side of the fixed portion with a front surface facing upward.

Abstract: In a laser machining apparatus that performs machining by a laser beam (4) emitted from a laser oscillator (1), the laser machining apparatus herein provided includes an aperture (5) placed in a light path of the laser beam (4) emitted from the laser oscillator (1) so as to block a perimeter portion of the laser beam (4) and to transmit a middle portion thereof, and a beam-power measurement sensor (6) for measuring beam power of a laser beam (20) transmitted through the aperture (5), whereby it utilizes that beam power of the laser beam transmitted through the aperture (5) significantly changes (the more degraded, the more the beam power rises) due to a degradation condition of an output mirror (2) when the output mirror in the laser oscillator (1) becomes in high thermal loading condition due to the laser beam with high beam power, so that the degradation condition of the output mirror (2) is determined.

Abstract: A flexible pipe which can be heated efficiently, and may therefore be used for conveying oil in cold regions, is provided. The pipe comprises in order from inside to outside: an interior lining; a wound tape; and at least one reinforcement layer. The wound tape contains a first exterior layer of a plastics molding composition that is not electrically conductive; an intermediate layer of an electrically conductive plastics molding composition; and a second exterior layer of a plastics molding composition that is not electrically conductive. A volume resistivity to IEC 60093 of the intermediate layer is in the range from 10?3 to 1010 ?m, and the intermediate layer comprises at least two metallic conductors embedded into the plastic molding composition along an entire length of the tape in such a way that, the two conductors do not touch one another.

Abstract: A seam welding apparatus and a seam welding method perform a seaming process on workpieces of various shapes having flange sections, by preventing a welding track formed by upper and lower rotary electrodes from becoming displaced from a welding reference line established on the flange section. The seam welding apparatus includes two rotary electrodes for gripping the flange section therebetween while seam-welding the flange section, a support for synchronizing movements of the two rotary electrodes with each other in a widthwise direction of the flange section, a turning mechanism for pressing at least one of the two rotary electrodes toward the workpiece body, a roller that abuts against an end face of the flange section, and roller adjusting means for positionally adjusting the roller.

Abstract: In order to evaluate the welding current for the resistance seam welding of an overlap seam of container bodies, a welding with changing welding current intensity is carried out for a container body of the production series, resulting in a changing welding of the seam, ranging from the welding with a too high temperature to the welding with a too low temperature. The electric energy for this welding is determined several times during this welding and/or the temperature of the weld seam is determined several times and the welding current intensity is determined at which the welding of the individual container body is too cold and the welding current intensity at which the welding is too hot. This determination is based on the determined electric energy values and/or on the determined temperature values and based on this determination a preferred range for the welding current intensity within these limits of too hot and too cold is determined.

Abstract: A method of making a structural connection in a metallic tubular assembly is provided. It comprises providing a node having at least two legs and forming a radially extending rib extending from an exterior surface of each of the legs by deforming a corresponding interior portion of each of the legs. At least one tube is provided having a radially extending flange adjacent an open end. The tube is placed over the exterior surface of one of the legs abuts the radially extending flange and the radially extending rib. By applying opposing forces to one of the legs and one tube to hold the radially extending flange and the radially extending rib in abutting contact at a joint, resistance welding can take place at the joint when at least one electrode is applied to the joint.

Abstract: A closure assembly for an inflator comprises a housing and an outlet plate disposed within the housing. The outlet plate has an outlet opening configured to receive a burst disk. The outlet plate is joined to the housing by a deformation resistance weld. The deformation resistance weld is formed by contacting the outlet plate with a first electrode, contacting an exterior portion of the housing with a second electrode, and applying a voltage through the first and second electrodes to adhere a portion of the housing to a portion of the outlet plate.

Abstract: The present invention concerns a method for forge welding of tubes, rods, bolts or other axial symmetrical profiles. According to the methods the profile ends are formed by plastic deformation and/or machine cutting processes, such that they obtain a reduced cross section/thickness, the profile ends are locally heated electromagnetically by induction and/or direct high frequency resistance heating and profile ends are then pressed together. The forming step comprises given one of the profile ends a double arched shape. Preferably the other profile end is given a convex shape.

Abstract: Apparatus and methods for assembling solar receiving tubes in the field are described. In one embodiment, a welder is provided having longitudinally adjustable clamps that permit the easy restraining and adjustment of tube position for welding. In another embodiment, a system for moving along the length of a solar collector and sequentially welding tubes is described.

Abstract: A method of producing coil plate on a hot strip mill is disclosed. The method includes coiling hot rolled coil plate strip at a temperature that is selected (a) to minimize precipitation of Cr/Mo carbides or (b) so that any Cr/Mo carbides that form are sufficiently fine that they go into solution in any subsequent heat treatment of coil plate made from the strip.

Abstract: The present invention provides a method of production of electric resistance welded steel pipe able to stably reduce weld defects due to oxides by firing plasma and furthermore able to reduce plasma jet noise and comprises shaping steel plate 1 into a tube and electric resistance welding the abutting end faces 4 during which blowing on at least the abutting end faces 4a in the region 6 at the welding upstream side from the weld point 9 where the temperature becomes 650° C. or more a reducing high temperature (pseudo) laminar plasma obtained by applying voltage to a reducing gas containing H2 gas: 2 to 50 vol % to which is added a balance of Ar gas alone or a mixed gas of Ar gas to which N2 gas, He gas, or both are added. At that time, it is preferable to make the applied voltage over 120V and the make the plasma blowing conditions satisfy the following formula (1).

Abstract: Trailer for carrying a welding unit for butt-welding pipe portions, comprising a chassis with brackets for supporting and locking the body of a welding unit for butt-welding pipe portions, the chassis being provided with at least one pair of steered wheels, which can be oriented by means of a drawbar, and at least one pair of driving wheels, which are actuated by an electric motor, which in turn is powered by a current generator which is provided, together with the associated internal-combustion engine, on board the trailer; the chassis also supports a hydraulic pump and a hydraulic unit to which the hydraulic components of the body of the welding unit are to be connected, and an electrical unit for connecting the electrical devices with which the welding unit is provided; the chassis is provided with a fuel tank for the internal-combustion engine and an oil tank for the pump, the hydraulic unit and the hydraulic components of the welding unit connected to the pump; in this manner, the welding unit can be mov

Abstract: In an electric resistance welded steel pipe with excellent weld toughness for a line pipe, the area fraction of minute defects each having a maximum length of less than 50 ?m in a projection plane of an electric resistance welded seam is in the range of 0.035 to 0.000006, and the absorbed energy at ?40° C. measured by a method for an impact test of metallic materials is 100 J or more.

Abstract: A cartridge heater, especially a compressed cartridge heater (1) has at least one heating coil (8, 9), which is arranged exposed in a metallic tubular body (2) and is embedded in a granulated insulating material. The ends of heating coil portions (8, 9) are provided with terminals (7) projecting from the tubular body (2). To make it possible to manufacture such a cartridge heater with minimal effort in terms of labor and material, a flat insulating plate (10) coordinated in its width with the internal diameter of the tubular body (2) is provided as the carrier. The heating coils (8, 9) extend along the two flat sides of the insulating plate (10) and the two heating coils (8, 9) are connected to one another by a coil section (12, 12?), which is led around a deflecting edge (27) of the insulating plate (10).

Abstract: An electrical resistance heater element has a metal tube containing an electrical resistance coil that is electrically insulated from the metal tube by magnesium oxide powder, the coil being bonded to a conductor pin that protrudes from an open end of the tube. The powder is sealed against moisture by placing at least the open end of the tube within a chamber and immersing the open end within liquid silicone. A gas is pumped into the chamber to pressurize the silicone sufficiently to cause some of it to encroach into the powder through the open end of the tube. The heater element is installed within a heat exchanger with the silicone remaining uncured.

Abstract: An electrical heater bundle has heater elements, each including a metal tube, an electrical resistance coil within the tube, a conductor pin connected to the coil and protruding from an end of the tube, and an electrical insulation powder surrounding the coil within the tube. A conical cavity is located in the insulation powder at the end of the tube, the cavity extending from an inner diameter of the tube to the conductor pin. The cavity is filled with an epoxy that is cured in place. The insulation powder may have an infiltrated layer at the cavity that is an uncured liquid silicone. The heater elements are mounted to a header plate, and the elements associated with the three different phases of electrical power may protrude past the header plate at different distances.

Abstract: An apparatus and a system for separating dice from a substrate are described herein.

Abstract: A protection circuit, configured to detect and suppress electrical pre-arcing and arcing conditions in a resistive heater wire circuit, comprises a transient voltage suppressor, signal level sensing load coupled to the output of the voltage suppressor, detection and control circuitry, and a high-speed switch or electrical gate. The control circuitry is configured to control the operation of the switch, coupled between said control circuitry and the heater wire, wherein the switch is opened in response to an electrical pre-arcing or arcing condition or a short circuit condition.

Abstract: A method and a system for resistance seam welding of a foil and at least one foil support of a fuel cell system. During welding, the thin foil, together with the thicker foil support, is moved relative to the roller electrode while resting on a flat support element. In a suitable welding system, a counter-electrode is designed as a flat support element, such as a welding strip, that is displaceable relative to the roller electrode, the roller electrode being in rolling contact with the foil support, but not with the foil. Depending on whether one foil is to be welded to one or two foil frames, the support element may be designed having a high or a low specific electric resistance.

Abstract: A welding process in which fixture pipes 3 are resistance welded to opposite ends of a hollow stabilizer's suspension arm 1 for a vehicle and thereafter, these two parts are subjected to arc welding, but with a first step of the ends of the hollow stabilizer's suspension arm upset to form thick wall portions before resistance welding and arc welding are performed. The initial resistance welding retains the two parts in place for the arc welding step.

Abstract: In high frequency welding apparatus in which high frequency electrical heating current is supplied to metal surfaces to be welded together by contacts engaging the metal which is advanced toward a weld point, the contacts engage the metal in advance of the weld point and have contact faces with downstream edges contacting the metal. The downstream edge of one of the contacts, or the downstream edges of the both of the contacts, is or are skewed with respect to the path or paths of the metal surfaces to be heated so that the downstream edge or edges extend at an acute angle of about 35.degree. to about 55 .degree. with respect to the path or paths of the metal surface or surfaces, the angle being intermediate the contacts and the weld point.

Abstract: An electric heating element having a central conductor and an outer metallic sheath is welded to a base of vessel to provide a heating container, for hot water in a domestic appliance for example. In order to carry out the welding, the vessel is heated up by an induction heater to a certain temperature and the temperature of the actual contacting welding surfaces raised above the certain temperature to a fusing temperature by applying and controlling electric power supplied to the conductor while the heating element is held firmly in position against the base.

Abstract: An apparatus and method for welding a bracket to a tube are disclosed. A bracket having a semi-cylindrical portion with an inner surface and a radially inward projection extending from the inner surface is positioned adjacent to a tube with the semi-cylindrical portion of the bracket coaxially nested about the tube and with the radially inward projection engaging the tube at a faying surface. A resistance welding apparatus having a controller, an actuator, and a power supply is then provided. The power supply is coupled to the bracket and the tube through respective electrodes. A transducer cooperates with the electrodes to provide an output indicative of the position of the electrodes. A controller cooperates with the transducer and the power supply wherein the controller regulates the power output of the power supply as a function of the displacement between the electrodes to ensure that the bracket is properly welded to the tube.

Abstract: A thermal reactor to carry out a chemical reaction under precise and controlled temperature conditions. In a preferred embodiment, the reactor supplies a carbon-laden atmosphere with a predetermined carbon potential to a heat treatment furnace. The reactor has a sealed chamber, in which a chemical reaction is carried out. The chamber forms an electrical resistance element in order to produce within it the reaction temperature conditions. The chamber further being electrically isolated, having an inlet for supplying reaction products, and an outlet for the products coming from the reaction. Temperature measuring thermocouples are positioned on the chamber to determine, accurately and locally, the temperature required for the reaction. Carbon potential is measured by a probe arranged at the chamber's outlet.

Abstract: In a seam welding process for overlapping sheets, in particular for welding can bodies, the welding force is momentarily reduced upon each insertion of a can body between the welding rollers. This keeps the welding pressure constant even at the start of a can body. In this way the power input to the sheet can be kept constant even at the start of a can body, and the weld quality even at the start of a can body satisfies requirements.

Abstract: A multifunction laser assisted processing apparatus can perform cutting processes, marking processes and drawing processes on a workpiece material. The apparatus includes a laser beam source, a work face to support the workpiece material, an X-direction movable arm on the work face, and a Y-direction movable process head to project laser beam on the workpiece material. The apparatus further includes an output adjustable mechanism to adjust the amount of the laser beam from the laser beam source. The adjustable mechanism in one embodiment has a gas control device for keeping the pressure of laser medium gas at constant level, and a DC high-voltage power unit capable of adjusting the resonance and supplying it to the laser beam source.

Abstract: The machine of the invention, intended for resistance butt welding of pipes, comprises two semi-housings mounted externally on the pipes to be welded to the opposite sides of a joint and interconnected by the flash and upset drive, a clamping device mounted in each semihousing, including radially arranged hydraulic cylinders with clamping shoes, and a control system of the hydraulic cylinders.The control system of the hydraulic cylinders includes control valve units structurally associated with the piston rods of the hydraulic cylinders. The control valve units include follow-up spool valves interconnected by their common actuator linkage.

Abstract: A method for the production of an electric seam welded steel pipe for oil-well use which has good resistance to collapse pressure and souring, by providing a steel containing 0.08-0.26% C by weight, 0.8-1.9% Mn by weight, 0.5% or less Si by weight, the remainder being Fe and unavoidable impurities, subjecting the steel to hot rolling, and hardening, and coiling the treated steel at a temperature not exceeding 250.degree. C., after which the steel is then formed into tubular form and welded by electric resistance welding to produce an electric seam welded pipe, and the weld heat affected zones of the pipe are subjected to heating to a temperature of 900.degree. C. or more to effect hardening, and then the whole pipe is tempered.

Abstract: A method and apparatus for creating a circumferential seam weld in surrounding relationship to a cylindrical workpiece. The workpiece is moved continuously along a work path at a preselected velocity, and is simultaneously supported for free rotation about its longitudinal central axis. The workpiece moves into engagement with opposed surfaces defined by a pair of electrodes, one of which moves relative to the other and relative to the workpiece for causing rotation of the workpiece through approximately one-half revolution, whereby the two electrodes simultaneously form two welds which are about 180.degree. apart and which may individually extend up to a total angle of rotation of about 180.degree., or slightly in excess thereof, so that the welds overlap.