Abstract: An internal bore welding torch assembly and method for use in making remote arc welds inside metal tubes. The torch assembly includes a torch body unit of plastic electrical insulating material, to which is connected the necessary welding services of coolant, shield gas, and electric power. The body unit contains a removable and rotatable welding wand which is made of flexible plastic and has a welding electrode oriented radially at its outer end. For making a weld, such as for repairing a damaged tube, a metal sleeve is first inserted into the tube the flexible welding wand is then inserted into the tube and the radial electrode positioned adjacent an end of the sleeve. The flows of coolant and shield gas are provided through the torch body unit to the wand, and the wand is rotated while making the metal arc welds desired to seal weld the sleeve ends to the tube.

Abstract: Prior to effecting a repair of a leaking heat exchanger tube by an internal repair tube brazed to the leaking tube, strain in the leaking tube is measured while heating it to brazing temperature. A braze is only effected if the strain is below a predetermined level. Apparatus for carrying out the strain measurement typically of probe form having a strain gauge head (21) at the nose of the probe and a heater element (23). Preferably, the length of the probe is such that the head (21) reaches to just above a grid support plate (12). Where strain is found to be above said predetermined level and the leaking tube is of U-shape the strain may be relieved by heating both legs of the tube. Alternatively, strain may be relieved by thinning and bulging the leaking tube (FIGS. 5A-C) at a region close enough to the braze for the thinned zone to experience heat from the braze to allow it to yield under the strain.

Abstract: A tube sheet welding apparatus for the rear or back face of a tube sheet. The welding head apparatus includes a welding head housing with an internal opening therethrough. The particular tube to be welded is to be located through the internal opening. The welding head housing is to be separatable into two separate halves and to be clamped tightly onto the tube to be welded. The welding electrode is mounted within a welding electrode housing which is located within the welding head housing. The welding electrode, as well as the welding electrode housing, is rotated through a gear assembly to complete the welding operation of the tube to the tube sheet. After welding, the welding head housing is split apart permitting separation of such from the tube that has now been welded permitting movement of the welding head housing to another tube that is then to be welded. Inert gas is to be supplied to the welded area through an inert gas passage assembly located within the welding head housing.

Abstract: The welding head assembly for welding together a pair of cylindrical tubes wherein one of the tubes protrude along with a mass of other similar tubes from a tube sheet. To precisely locate the welding head position at an exact position for each and every produced weld there is utilized a locator plate assembly which is to be fixedly mounted a precise distance from the tube sheet directly on to the tube which protrudes from the tube sheet. The locator plate assembly includes a position locator mechanism which connects with the face of the tube sheet to precisely locate the locator plate assembly a precise distance from the tube sheet. A location gage assembly is to connect with the locator plate assembly to initially establish the desired position for the locator plate assembly. Upon removal of the location gage assembly from the locator plate assembly, a welding head is to be engaged with the locator plate assembly.

Abstract: In order to join a tube to a tubesheet of a heat exchanger, the end of the tube is inserted into a socket at the end of a hole that passes through the tubesheet. The socket is large enough to receive the tube, but the hole is not, so the tube bottoms out in the socket and is thus located both radially and axially by the socket. A ring mold is fitted around the tube and moved against the tubesheet, so that its end fits into an annular groove that surrounds the socket in the back face of the tubesheet. The ring mold has a chamfered confining surface that surrounds the tube where the tube emerges from the socket. Once the ring mold is in place the portion of tube that is within the socket is welded autogenously to the tubesheet by rotating an electrode within the hole. The molten weld metal flows outwardly to the confining surface, but is prevented by that surface from flowing circumfentially, even when the welding is performed with the tube in a horizontal position.

Abstract: A method of welding ferritic stainless steel to austenitic stainless steel to form a corrosion-resistant welded article having a stabilized weld joint is provided. The ferritic steel contains 17 to 35% chromium and a total carbon and nitrogen less than the total carbon and nitrogen of the austenitic steel containing 16 to 29% chromium. The weld is stabilized with up to 4% stabilizer selected from the group consisting of titanium and columbium, and at least 0.5% stabilizer when the weld deposit contains at least about 22% chromium or at least 30% total of chromium and three times the molybdenum content, and at least 0.8% stabilizer for less than about 22% chromium or less than about 30% total of chromium and three times the molybdenum content. The source of the stabilizer may be the ferritic steel or austenitic steel or a weld filler metal.A corrosion-resistant welded article produced by the method is also provided, such as a ferritic stainless steel tube and austenitic stainless steel tubesheet.

Abstract: The pressure-differential method for sleeve-to-tube joining comprises inserting a sleeve within a tube and joining the sleeve to the tube. An internal heating device is then inserted into the sleeve for bonding the sleeve to the tube. The portion of the sleeve to be joined is then sealed so that the portion of the sleeve to be joined may be internally pressurized. Once the sleeve has been so pressurized, the heating operation may be begun. In the case of welding, as the welding progresses the molten weld pool under the arc is continuously driven by the internal pressure gradient toward the external tube. In this manner the arc force is cushioned by the molten pool at all times thus preventing the weld arc from piercing through the sleeve. In the case of brazing, as the heating progresses the sleeve becomes more pliable such that the internal pressure causes the sleeve and braze material to closely contact the inner surface of the tube.

Abstract: A welding apparatus for internally welding sleeves to tubes comprises a central shaft with an electrode attached thereto which are capable of being inserted in a tubular member. A plurality of remotely actuable seals are disposed on the welding apparatus and around the electrode for establishing a sealed chamber in the sleeve in which the welding may take place. The welding apparatus is capable of supplying an inert shielding gas to the sealed chamber for pressurizing the sealed chamber during the welding process and while the electrode completes a weld around the inner circumference of the sleeve. The apparatus may also be used to internally braze the sleeve to the tube.

Abstract: A method of securing a tube, such as a condenser tube for a refrigeration cabinet, to the inside of the outer walls of the cabinet by means of direct welding between the tube and the oil panel of the cabinet. The tubing is formed to the desired configuration and a plurality of projections are formed on the tube for welding to the surface by a crimping action which indents the sidewalls of the tube at each weld location to produce a projection beyond the normal tubing wall while the rest of the tubing remains undeformed. Subsequently, the configuration of tubing is placed on the sheet and resistance-welded under conditions to produce a relatively light weld adhesion with a small weld nugget that does not create any significant discoloration or distortion on the other side of the sheet which becomes the finished exterior surface of the cabinet.

Abstract: Welding of tubes to tube plates using a non-consumable electrode to locally melt the wall of a tube and an adjacent area of the tube plate where the tube has been entered into a hole in the tube plate and including an initial weld preparation comprising the machining of one face of the tube plate to produce respective annular grooves concentrically around the holes into which the tubes are subsequently to be entered for welding.

Abstract: The h.f.-heated edges of a split tube are prepared prior to heating by means of contour-rolling the edges in order to obtain a convex contour in which the temperature is isothermically distributed, parallel to the convex edges.

Abstract: A tube welding apparatus for the front face of a tube sheet. The welding apparatus includes a welding head housing from which protrudes a securing mandrel assembly. The mandrel assembly is to be positioned within the tube that is to be welded. The securing mandrel assembly includes a ball assembly which is to be movable to an extended position in tight contact with the interior wall of the tube. The welding electrode is to be selectively mountable in any one of various positions within a welding electrode mounting housing which is located within the welding head housing. The different positions of mounting the electrode physically orient the electrode at slightly different angles with respect to the weld area. Inert gas is to be supplied to the weld area through a gas discharge passage assembly. Included within the welding head housing is a gas diffuser to facilitate even dispursement of the gas about the tip of the welding electrode.

Abstract: Adjustment assembly for the rotary torch head of an electrical welding gun having a torchholder (4) supporting the welding electrode (3) and a filling wire nozzle (8) at the end of a wire feed tube (9) held in a swivel holder (11) arranged on torchholder (4) so as to be swivellably adjustable about swivel spindle (10) of filler wire nozzle (8). Torchholder (4) is swivellably adjustably held on longitudinal slide (5) about its swivel spindle (7), slide (5) being adjustably guided on a cross-slide (6) parallel to the rotation axis of the torch head. For fixing the clearance of the adjusting devices, a spring can be secured between the back of the torchholder (4) and drive shaft (15) of the torch head. The spring can be formed by the wire feed tube (9), which is secured so as to be resiliently bent out between filler wire nozzle (8) and torch head drive shaft (15).

Abstract: A mounting fixture for an automatic welding apparatus for precisely centering the rotating welding electrode within the welding area. The mounting fixture is mounted onto a portion of the workpiece adjacent the welding area. An indexing device is connected to the welding fixture housing which is to determine the precise location for the welding electrode. The mounting fixture is to be movable a limited amount determined by the position of the indexing device. Once the precise position of the indexing device and the mounting fixture has been obtained, the mounting fixture is fixed with respect to the workpiece. An automatic welding head is then mounted on the mounting fixture and the now precisely located welding electrode is then to be utilized to produce the desired weld.

Abstract: A method of continuous welding of a series of tubes to a tube sheet, in which the torch current is decreased to produce partial fading of the arc after completion of the first welding bead, and the torch is then moved to a starting position on a second contour to be welded. A stationary preheat is then effected, and a second weld bead is made by following the second contour to be welded. The process continues until the last bead has been made, whereupon the arc is switched off.

Abstract: A hand-held welding torch is disclosed having a pair of foldable handles to ermit maneuvering of the torch in confined spaces. The torch is of the type having a non-consummable electrode radially mounted on a longitudinal shaft which can be inserted into the bore of a tubular member and rotated so that the tip of the electrode moves over a circular path around the axis of the tubular member. In one preferred embodiment, a front handle is coupled to a spring-loaded collet having an expanded end and mounted for axial movement about the shaft upon actuation of the front handle. A set of radially-projecting jaws pivotally mounted immediately about the collet are spread outward to positively grip the bore by movement along the expanded end so that the torch is properly positioned in substantially the center of the bore and supported therein during rotation of the electrode.

Abstract: A continuous tube welding method which locates each tube and then moves a welding torch in orthogonal X, Y directions to form a continuous weld over a plurality of tubes disposed in a plurality of rows. The tube location is indicated by a probe which also measures tube diameter.

Abstract: A welding torch made of a high temperature plastic which fits over a tube intermediate the ends thereof for welding the juncture between the tube and the back side of a tube plate and has a ballooned end in which an electrode, filler wire guide, fiber optic bundle, and blanketing gas duct are disposed.

Abstract: A method of longitudinally seam-welding steel pipes comprises the steps of providing a conductive net-like enclosure tube around a cable for supplying a direct electric current from the power source to the welding head; and conducting a direct electric current through the enclosure tube and through the steel pipe in a direction opposite to that in which the direct current runs through the cable. Apparatus for longitudinally seam-welding steel pipes comprises an electrical cable coupled to a welding head, a net tube surrounding the cable, and a device for supplying a direct electric current to the cable in a first direction and to the net enclosure tube and steel pipe in the opposite direction. The direct currents flowing in the enclosure tube and in the steel pipe is adjustably controlled to minimize the magnitude of a magnetic field created around the net enclosure tube and producing a welded steel pipe seam.

Abstract: Welding apparatus utilizing a continuous belt in conjunction with a slidable guide pin and spindle disposed in a carriage that causes a welding torch to form a circumferential weld when the guide pin is in a tube and moves the torch rapidly between the tubes when the guide pin is retracted from the tubes.

Abstract: A welding torch is rotatably mounted in a carriage. The carriage and welding torch are driven by motors and driveshafts mounted on a base to provide a light carriage which can be rapidly accelerated as the torch moves from tube to tube when forming a continuous weld encompassing the juncture of a plurality of tubes.

Abstract: A multiple electrode magnetic arc welder that has a plurality of electrodes arranged in a preselected pattern corresponding to the arrangement of the multiple welds to be made by these electrodes in sequence. Each of these electrodes is mounted for movement from a retracted inoperative position toward the respective work areas where the welding takes place and back to the retracted position. The electrodes are moved individually into close proximity welding position to its workpiece for welding the workpiece and then retracted to inoperative position with the means for retracting the electrodes comprising means for automatically de-energizing the retracted electrode. The disclosure also includes a supply of pressurized inert gas and a valve for bathing the electrode and the workpiece in this inert gas automatically during the welding operation when the above close proximity position is maintained.

Abstract: A welding apparatus including a nozzle assembly having a contact extension and a contact tip for guiding a consumable welding wire into a tube hole. The consumable welding wire is guided into the tube hole and an electric current is passed to the wire to produce an arc between the tip of the wire and the sidewall of the tube hole, melting the wire and supplying filler weld to the hole. The nozzle assembly has a gas nozzle; and, during the welding process, an inert gas is delivered into the tube hole through the gas nozzle.

Abstract: In a method of welding a thin titanium tube to a titanium or titanium clad header of a heat exchanger, the titanium tube is inserted into a hole formed through the header and then the body portion of a core is inserted into the hole of the header. The core is provided with a support and a circular flange at a joint between the body portion and the support. The flange is provided with a notch extending radially inwardly of the flange. When the core is inserted into the hole of the header, the flange comes to engage the header and then the front end of an electrode is positioned in the notch to generate an electric arc, while rotating the core or only the flange, between the front end of the electrode and a portion of the header radially separated by a predetermined distance from the titanium tube. Thus, the header and the titanium tube are melted and welded by the arc.

Abstract: Semi-automatic welding apparatus is suspended from a plug body vertically force fitted into the end of a tube to which the plug is welded. The plug body configuration is disclosed, along with the internal arrangement it provides for suspending the welding apparatus. A mandrel is depicted in its movable parts which enables it to be manually linked between the plug body and welding apparatus.

Abstract: Gas-shielded, arc welding apparatus for securing a tube to the sidewall of a pipe or the like and facilitating removal of the welding apparatus after completion of the weld includes a locating fixture adapted for clamping engagement with the pipe and for positioning a welding head with rotary guide means coaxially aligned with the tube, a welding torch assembly being supported for rotation upon the guide means and supplied with power during rotation for welding the tube to the pipe.

Abstract: A welding apparatus including a nozzle assembly having a contact extension and a contact tip for guiding a consumable welding wire into a tube hole. The consumable welding wire is guided into the tube hole and an electric current is passed to the wire to produce an arc between the tip of the wire and the sidewall of the tube hole, melting the wire and supplying filler weld to the hole. The nozzle assembly has a gas nozzle; and, during the welding process, an inert gas is delivered into the tube hole through the gas nozzle.

Abstract: A tube-type vessel, such as a heat exchanger, has tubes that extend away from a tubesheet provided with holes which axially align with the tubes and open into the tube interiors. The diameter of each hole in the tubesheet is less than the outside diameter of the tube with which it aligns, but is greater than the inside diameter of the tube, thereby producing an offset between the inside surface of the tube and the surface of the hole. The tubes are attached to the tubesheet by welds, and each weld forms a fillet between exterior surface of its tube and the back face of the tubesheet and further forms a smooth beveled transition between the inside surface of the tube and the surface of the hole. The fillets eliminate the crevices that surround the tubes in conventional structures, and as a consequence no material will build up around the tubes and collapse them. To unite the tubes with the tubesheet, the latter at each hole is provided with a socket into which the end of a tube is fitted.

Abstract: This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.