Abstract: A method for fabricating a threaded fastener having a discontinuous coating of a contaminant-inhibiting coating material. In a preferred embodiment, the threaded fastener is formed so as to provide a coated fastener with substantially coating-free crests. The article resulting from the fabrication method also forms a part of the present invention. The resulting threaded fasteners include electrically conductive portions, allowing use of the fasteners in fabricating structural assemblies using welding techniques.

Abstract: A weld monitoring and evaluating circuit (10) for non-destructively determining if a just-completed weld is a satisfactory or an unsatisfactory weld. The circuit is used to derive the temperature at the weld zone in real time by determining the total power input to the weld zone, taking into account losses experienced at the weld zone, and dividing the result by the thermal mass of the weld zone. The predicted temperature at the weld zone is compared against an electrical signal representing at least a minimum desired welding temperature needed to be attained at the weld zone to produce a satisfactory weld at the time that the stud (16) contacts the weld pool (18a) (e.g., the "plunge event"). If the derived weld temperature signal has exceeded the reference signal at the time the plunge event occurs, then it is assumed that a satisfactory weld has occurred.

Abstract: The invention relates to a welding process for drawn arc stud welding wherein after ignition of the main current electric arc, the latter's voltage (U) is measured and, depending upon the measured voltage, the current flow of the continued main current electric arc and/or the dipping movement of the parts which are to be welded together, is regulated or controlled.

Abstract: Disclosed is a stud for a boiler or other high temperature application, such as a furnace. The stud is made of an iron aluminum alloy which comprises about 81 to 91 wt. % iron, about 8 to 13 wt. % aluminum, about 0.01 to 0.3 wt. % carbon, and zero to about 3 wt. % of a refractory metal and/or zero to about 1.5 wt. % zirconium. The studs are welded to a surface of a component of the boiler or furnace by arc or resistance welding. The aluminum of the iron aluminum alloy imparts good oxidation and sulfidation resistance to the studs. The alloy also has a good electrical resistance which makes the alloy especially useful for arc or resistance welding. The aluminum content acts as a getter to eliminate gas porosity in the resulting welds. The present invention is particularly useful for making boiler heat exchange surfaces or refractory covered surfaces wherein the studs function as refractory anchors.

Abstract: A pin-type fastener capable of dual-function includes a pin which can be used in fastening workpieces together. The pin has a pintail capable of being removed from the remainder of the pin after the pin has been installed as a fastener in a workpiece, and the pintail can then be used as a weldstud and welded to the same workpiece as the pin-type fastener, or to another workpiece. The pin-type fastener can be a two-part fastener, for example a lockbolt including a nut or swageable collar engageable with the pin. The pin may have a breakneck to facilitate removal of the pintail. The pin itself may be a weldstud. In use, the pin-type fastener is installed in a workpiece and the pintail is removed, and then the pintail is used as a weldstud, being welded to a workpiece. Electric welding is employed. The advantage of the fastener is in economy through second use of the pintail as a stud.

Abstract: The connection of structural component parts in adjusting devices for seats, in particular for motor vehicle seats, is disclosed. In connecting structural component parts for adjusting devices for seats, the structural component parts to be rigidly connected with one another are welded in their connecting region. In order to prevent distortion of these structural component parts caused by the welding process, one structural component part has at least one bevel which projects toward the connection side and can be pressed into at least one recess of the other structural component part during a capacitor impulse welding process, this recess substantially conforming to the bevel with respect to shape and dimensions.

Abstract: Arc welded joint between a carrier and a metal component with a continuous recess into which a stud-like weld-in part is introduced, wherein the weld-in part which consists of a shank and an enlarged head is pressed into the recess and into the pool of melt formed on the carrier so that the pool of melt adjacent to the wall of the recess embraces the outer rim of the head, the pool of melt directly connecting the component to the adjacent carrier. The rim of the head may be designed as a radial melting edge which is located completely within the recess of the component and has a substantially blade-like cross section.

Abstract: A stud which is automatically fed so as to welded stably and properly, has a large electric contact surface with the collet, facilitates clip attachment, and maintains the engagement firmly after the attachment of the clip. A stud 1 extends upwardly into a rod-like form which is threaded on its periphery, and includes a welding tip at the lower end thereof for welding to a base member such as a panel so as to be used in mounting a member to be attached on the base member. The stud 1 is formed to be short in overall length and its welding tip is formed as a flange 4 whose diameter is larger than that of the rod-like body. A crest 6 of the screw 3 is formed flat. An upper flank angle 8 of the screw is formed large while a lower flank angle 10 of it is formed small. An edge 12 of an upper end 11 of the stud is chamfered.

Abstract: A welding comprises placing the end of a stud supported by a welding gun on a welding portion of a workpiece, producing an arc discharge across the stud and the workpiece, melting the end of the stud and a portion of the workpiece and bringing the end of the stud so as to abut on the melted portion of the workpiece. A hollow cylindrical member 21 is prepared so that the material has a larger inside diameter than an end 20 of a stud 19 and is made of a magnetic permeable material is prepared. During the arc discharge, the cylindrical member 21 is placed so that the hollow portion is positioned on the side of the workpiece opposite to the stud and corresponding to the end of the stud.

Abstract: A system (10) and method for predicting weld quality in a stud welding system by measuring the displacement of a movable shaft (20) with respect to the gun body (12) during the weld process. A sensor (34) is positioned with respect to the welding system in order to produce a series of discrete signal values each indicative of this displacement. These values are plotted graphically and used to produce a weld "signature" which can be compared with signatures of welds of known quality to more accurately predict the quality of the current weld. Based on these weld signatures, various weld parameters including current, time and lift can then be adjusted until a consistent signature indicative of good weld quality is produced.

Abstract: Arc welded joint between a carrier such as aluminium sheet as one electrode and as the other electrode a metal component with a continuous recess into which a stud-like weld-in part is introduced, wherein the weld-in part consists of a shank and a head which is enlarged in relation to the shank diameter via a step, penetrates into the recess in the component resting on the carrier and can be pressed into the pool of melt formed on the carrier so that the pool of melt adjacent to the wall of the recess embraces the outer rim of the head and the step, the pool of melt directly connecting the component, at least in the region of the edge of the wall of the recess facing the carrier, directly to the adjacent carrier.

Abstract: In order to be able to weld on studs (2) with a larger than normal diameter, a stud-welding process is proposed in which the pressure applied to the stud (2) before the welding current is triggered is applied symmetrically to the stud axis (A), but extra-axially and adjustable as appropriate, thus ensuring better centering during the welding operation and also improving the quality of the weld. A suitable pressure-application device (27) is proposed for this purpose.

Abstract: The invention relates to a process for the electric welding of two weld parts by the flow of electric current through a welding point and the use of fluid such as an inert or protective gas to inhibit or prevent or eliminate oxidation at the welding point. The fluid is supplied through a continuous bore in one weld part and is directed toward the welding point, so that the fluid sweeps over the welding point radially from the bore. The fluid may be an inert gas such as argon or nitrogen, optionally mixed with carbon dioxide; alternatively the fluid may be aqueous liquid, the water being vaporized in the region of the welding point.

Abstract: Method and apparatus for automatically compensating for spring fatigue and aging, mechanical wear, and the like in a stud welding machine. In order to hold plunge time at an ideal constant value, the plunge times of each weld are measured and a running average is generated to adjust the command to drop the stud onto the workpiece as necessary to hold plunge time substantially at the ideal constant value.

Abstract: Method and front-end fixture adapted for use with manually-operated electric stud welding guns, which permits the successful welding of a plurality of metal studs uniformly onto a workpiece. Various aspects of the invention provide for repeated accurate spacing of the studs as they are successively welded, for accurate alignment of a series of studs, and for each stud to be oriented in a disposition substantially perpendicular to the surface of the work piece. The preferred embodiments include a bracket mounted to a conventional welding gun, an alignment bushing mounted on the bracket forward of the chuck of the gun for contacting a previously-welded stud, and a footpiece mounted on the bracket rearward of the chuck.

Abstract: A welding accessory which includes an arc shield having outer and inner peripheral surfaces such that a weld can be formed within the inner peripheral surface as the arc shield shields the weld form external air during forming of the weld. The arc shield includes a ceramic material having not less than 40 weight % of boron nitride. The arc shield may be formed of a composite of boron nitride and silicon nitride, a composite of boron nitride and alumina nitride, a composite of boron nitride, aluminum and silicon nitride, or a composite of boron nitride and zirconia.

Abstract: A welding apparatus welds shear studs onto a horizontal surface and uses ferrules as weld molds. The apparatus includes a weld module having a frame and having a welding gun with a chuck, the module being translatably mounted to a carriage, a holder mounted on the frame which holds a stud in a first position and a ferrule in a second position, and a driver which drives the weld module downward so that the chuck contacts the stud and drives a lower portion of the stud into the ferrule.

Abstract: An attaching assembly is disclosed which permits attachment of ceramic fiber to a back plate. The assembly includes a stud retainer plate having a perforation, such as at the center of the plate. The stud retainer plate can be affixed to a perforate backing element, e.g., a metal mesh. On the side of the stud retainer plate opposite the backing element, there is a tube retainer. This tube retainer is secured to the stud retainer plate. An elongated, removable tube can be inserted into the tube retainer. A stud can be inserted through the removal tube, and through the retainer plate perforation and perforate backing element. The stud is then welded to a back plate, e.g., a solid furnace wall. A refractory element inserted in the retainer plate perforation insulates the stud from the retainer plate to prevent arcing during welding.

Abstract: Method of controlling stud-welding apparatus wherein the lifting coil is essentially current and voltage free at the beginning of the plunge stroke but the plunge stroke is damped by a pulse current applied to the lifting coil a very short time before impact and ceased when the stud contacts the workpiece.

Abstract: A method of stud welding stainless steel studs to carbon steel or low alloy steel components with formation of a ductile weld therebetween. The chromium equivalent and nickel equivalent of the steel component is determined and a stainless steel stud provided that has a chromium equivalent and nickel equivalent content which, upon dilution thereof by steel of the component during stud welding, will provide a structure of austenite plus ferrite in the resulting weld structure, and stud welding the specified stainless steel stud to the steel component.

Abstract: Apparatus and a method of using it to straighten a dent in a sheet metal workpiece are provided. The apparatus includes a stud welding gun to releasably grip a stud and weld it to the dent, as well as integral hammer means to apply force to the welded stud, straightening the dent. The apparatus and the method of use then provide means for dewelding the stud from the straightened workpiece, thereby avoiding the usual stud cutting and grinding operations. Exchangeable electrodes are provided so that the apparatus can be used for both stud welding and spot welding.

Abstract: A welding apparatus for welding a new stud on to the end of a broken-off stud which comprises a conventional mig welding hose through which inert gas can pass and through which a mig welding wire can be fed, the hose having a conventional extension at one end thereof for attachment of a mig welding nozzle thereto, the extension also having a longitudinally extending contact tip guide attached thereto and through which the welding wire passes, the nozzle having an enlarged cylindrical portion which is received over the extension of the hose, and a reduced cylindrical portion extending over and beyond the contact tip guide in concentric relation thereto. The mig welding hose has a trigger for initiating the flow of inert gas through the hose and into the annular area between the guide and the nozzle, for supplying a d.c. welding voltage and for feeding the wire through the hose and through the contact tip guide.

Abstract: A welding system for welding a new stud onto the end of a broken-off stud which comprises a welding gun having a forward end and a rear end, the forward end of the gun supporting a new stud to be welded to the end of a broken-off stud, the new stud being threaded at least along a rear portion thereof, a shroud mounted at the forward end of the gun and surrounding the new stud, the forward end of the new stud projecting outwardly from the gun into the shroud, the new stud having a longitudinal bore extending from the rear end thereof to a location adjacent to the forward end thereof where the bore flares outwardly to a larger bore at the forward end of the new stud, the new stud also being provided with slots at the forward end diametrically opposite from each other and in the region of the enlarged bore, a coated welding rod supported by the gun and extending from a location adjacent the rear of the gun through the bore in the new stud and to a point adjacent the forward end of the new stud, the welding rod h

Abstract: A resistance welding pin for connecting insulation batts to ducts comprises a head having a shank and a sharpened tip remote from the head. The shank, adjacent the tip, includes an abutment against which a welding electrode may bear, the electrode being passed through an aperture or passage in the head.

Abstract: A method and apparatus are provided for welding a stud to a workpiece and maintaining the area around the weld substantially free of smut. The existence of the smut detracts from the appearance of the workpiece and, if the workpiece is to be painted or otherwise covered with a coating material, the smut must first be removed. A spark shield assembly has an outer end which is placed in contact with the workpiece around the stud. Anti-smut liquid is first deposited from the assembly on the weld area around the end of the stud where the weld occurs thereby to eliminate the deposit of a coating of smut. Air is then directed through the spark shield assembly toward the outer end thereof after the weld is completed to aid in removing the anti-smut liquid from the spark shield assembly.

Abstract: Control circuit for arc welding components to workpieces, in which a component is placed on to a workpiece by a weld gun and after a welding stroke is lifted from the workpiece in a return stroke by igniting a pre-current arc and is brought up to the workpiece again in a forward stroke during the burning of an interconnected welding arc, in which a sequencing control determines the tripping moments of return stroke and forward stroke as well as of the welding arc and a monitoring voltage is bypassed from the pre-current arc ignited at the welding point, characterized in that the monitoring voltage (V) is converted into a correction voltage (line 27) by means of a set-point comparator (25) and is superposed on a control voltage (line 18) for principally controlling a high-frequency modulated switching mode power supply unit (15) and said switching mode power supply unit (15), in accordance with the thus corrected control voltage, adjusts its output current (lines 13,14) during the respective welding operation

Abstract: The method of electric-arc condenser-discharge percussion stud welding includes prepositioning a stud on an article, retracting the stud from the article while igniting an auxiliary arc between them, and moving the stud towards the article. While the stud is thus moved, the voltage drop across the auxiliary electric arc is measured, and from the value thus measured is subtracted the sum of electrode-adjoining voltage drops at the end of the stud and at the article, and when the voltage drop value thus obtained varies by 10 to 90 percent from the initially obtained value of the voltage drop, the discharge of the condenser is initiated. Then the stud is introduced into the molten metal of the article, and the end of the stud is butted with the article to form a welded joint.

Abstract: A method of attaching a connection piece of metal to a metal surface by brazing wherein the required heat is generated by an electric arc. The heat generated by the electric arc is conducted through at least a portion of the connection piece and melts a brazing metal provided between the connection piece and the metal surface. The heat conducting portion of the connection piece prevents direct contact between the electric arc, the metal surface and the brazing metal during melting which prevents disadvantageous thermal actuation of the metal surface. When the current to the electric arc has been disconnected, a mechanical force is applied to the heat conducting portion of the connection piece pressing the latter against the metal surface and pressing out a portion of the brazing metal from underneath the remaining joint-forming surfaces of the connection piece.

Abstract: A method of welding studs inclusive of a bolt or the like to an underwater structure or a land structure in the rain or for mounting anticorrosive members, wherein the tip of the stud held by the welding gun is enclosed by a resilient, heat-resisting water sealing member and a gas generating agent is applied to the tip of the stud. The water sealing member is brought in contact with a base metal and an arc is generated by a current across the stud and the base metal so that the arc heat causes gas to be generated from the gas generating agent to force any water around the stud tip out of the water sealing member under a gas pressure, and then the stud is welded to the base metal in the absence of water.

Abstract: Apparatus and method are provided for sensing the presence of arc discharge in arc welding such that the change in electric current is sensed at the time of discharge and light emitted from a welding position is sensed only when the sensed electric current surpasses a predetermined level.

Abstract: A method for joining individual pieces of material together includes the steps of heating the pieces to be welded together, at least one of which consists of a metal matrix with a relatively low melting point and a reinforcement material distributed therein, the reinforcement having a relatively high melting point. The other piece may be a similar metal matrix composite, or may be a metal or alloy which is to be joined to the first piece. The pieces are heated to a temperature which is above the melting points of the metals and below the melting point of the reinforcement. The pieces so heated are brought into contact with one another and then cooled to a temperature below the melting points of the metals. One technique for practicing the method of the invention is that of capacitor discharge welding.

Abstract: To attach a nut to a plate-shaped workpiece, especially to a metal sheet, in such a way that it has self-locking properties without additional aids or parts, the force fastening the nut and acting on a free thrust surface of the nut is divided into at least two effective components generating a shearing stress in the nut material, transverse deformation of a part of the nut facing away from the workpiece being produced, and the thread diameter in the thread region deformed for self-locking purposes being reduced, while at the same time the thread pitches are inclined towards the center axis. A nut which can be used either as a locking nut or as a non-locking nut is characterized by a force-deflecting design of the thrust surface.

Abstract: A stud welding gun has a forepart which includes the delivery end of an automatic stud-feeder and is secured to the housing by a quick releasable joint so as to be readily replaceable by another forepart supplying a stud of different size. The gun includes a pneumatic piston and piston rod which serves to push a stud into the collet after delivery to the gun. The piston rod is detachable from the piston and means is provided for locking it in the forepart so that it is replaced into the forepart for studs of different size.

Abstract: A solenoid power control circuit provides full power during lifting and reduced power during maintaining a lift condition in a lifting solenoid of an electric arc stud welding gun. During the stud lifting portion of a stud welding process, relatively high power is provided to the lifting solenoid to effect work necessary to accomplish the lift; but after a lifted condition has been achieved, the invention phases back power to reduce the energy dissipated while the stud and the lifting solenoid are maintained in lifted condition. A relaxation oscillator having two different charging time constants that can be selected to provide long or short phase delay is employed for the phase modulation control of lifting solenoid energization.

Abstract: A method and apparatus is provided for attaching forging handles in the nature of studs to metal billets. The billets are passed in end-to-end relationship through a furnace following which the heated billets are individually delivered to a welding station where a welder welds a stud to the billet. The welder includes a welding head which is shifted by a translation mechanism from a feeding position where studs are successively fed to the welder to a welding position in which the stud is brought into engagement with the billet and electrical current is delivered through the stud to produce the weld.

Abstract: An apparatus for welding studs to a workpiece includes a stud supporting and positioning unit adapted for cooperation with a guide template to provide for accurate positioning of a stud to be welded. The unit includes a centrally located electrode provided with a stud positioning bore and a detent for releasably supporting a stud within such bore; a casing or housing supported on and electrically insulated from the electrode; and a plurality of stud guide pins, which are arranged parallel to the stud positioning bore and supported for axially directed reciprocating movements under the control of spring devices between an extended, guide position and a retracted, stud welding position. The pins cooperate with guide holes provided in the template to accurately locate the stud to be welded. The method involves the mode of forming the template and cooperation of the positioning unit therewith to achieve accurate positioning of a stud.

Abstract: An industrial stud welding machine is provided with a chuck which defines a work piece receiving orifice of infinitely variable diameter. The stud welding chuck is thereby able to accommodate studs of different diameters, and is also adjustable to compensate for wear resulting from extended use. The stud welding chuck employs a barrel having an annular wall in which longitudinal slots are defined. The barrel is tapered and threaded externally. A collet encircles the barrel and is treadably engaged therewith. Advancement of the collet in one longitudinal direction squeezes the edges of the barrel walls together to reduce the work piece receiving orifice diameter. Advancement of the collet in the opposite direction along the barrel allows the work piece receiving orifice to open to a larger diameter.

Abstract: A large diameter stud and a method and apparatus for welding same are provided. The large diameter stud has a protruding tip at a weldable end thereof containing a solid rod-like body of flux. A ceramic ferrule which can have a two-step cavity surrounds the weldable end portion of the stud when engaged with workpiece to which it is to be welded. An arc blow coil surrounds the ferrule and is spaced therefrom with powdered flux therebetween and above the ferrule. The arc blow coil is attached to adjustable legs of a welding tool and has a weight thereon to aid in supporting the welding tool upright on the workpiece during the welding operation. In the welding cycle, a relatively low weld current is used for the main welding arc and is maintained for an extended period of time. Current through the arc blow coil is initiated when the welding cycle begins and is gradually increased to a maximum at an intermediate point in the welding cycle.

Abstract: A method for welding studs to a workpiece is provided. When studs are welded to workpieces using a drawn-arc, stud-welding technique, a coating of smut is sometimes deposited on the workpiece around the welded end of the stud. This coating detracts from the appearance and if the workpiece is covered with coating material, such as paint, the smut must first be removed, requiring an extra operation. It has been found that the coating of smut will not be deposited, if, during the welding cycle, fluid is carefully deposited on the weld area around the end of the stud where the weld occurs. This fluid consists of a small volume of low pressure air and an anti-smut liquid.

Abstract: The present invention relates to an arc-welding device for securing studs on metallic elements underwater, and comprising a head containing a chamber and of which the welding bead is obtained by means of a dielectric refractory ring placed around the base of the stud, wherein an annular space is provided between the stud and the ring and neutral gas is blown into the chamber through said space, to drive the water out of the chamber and keep up therein a gaseous atmosphere to facilitate the welding of the studs; the refractory ring is produced from borosilicate glass, rich in silica.

Abstract: Apparatus is provided for welding studs to a workpiece with the area around the welds being substantially free of smut. The existence of the smut detracts from the appearance of the workpiece and if the workpiece is to be painted or otherwise covered with a coating material, the smut must first be removed. The coating of smut can be eliminated if, during the weld process, fluid is carefully deposited on the weld area around the end of the stud where the weld occurs. The fluid consists of a small volume of low-pressure air and an anti-smut liquid. The latter also helps to keep weld splatter from adhering to the interior of a spark shield used with the stud. However, by applying a non-metallic, preferably plastic, sleeve within the spark shield, the problem of splatter can be further reduced or substantially eliminated.

Abstract: Method and apparatus for simultaneously welding by the stud end welding technique a stud having two or more ends. The stud includes at least one elongated relatively thin metallic projection from each end of the stud to be welded. The method and apparatus maintains a current density in a given projection sufficient to disintegrate the projection with consequent arc initiation. The resultant arcs melt all stud ends and plate. The molten ends are lowered into the pools at a controlled rate at which time the current is extinguished and the material solidifies.

Abstract: Apparatus and methods for replacing or repairing missing or damaged abrasion resistant wearbars utilized in high velocity cyclone boilers. A retrofit wearbar having an aperture therein is utilized in conjunction with an end weldable stud wherein the wearbar and stud are placed in position over a damaged wearbar or against the boiler tube in the case of a missing wearbar and the stud end welding technique utilized to fuse the wearbar and stud in place with the damaged wearbar or boiler tube in the case of a missing wearbar in situ. An arc shield is utilized which has a projection from the weld fillet cavity thereof which cooperates in conjunction with the aperture of the retrofit wearbar to provide alignment of the stud in the wearbar and prevent shorting of the stud to the wearbar during the welding cycle.

Abstract: Stud-welding device and procedure to mold a stud to a workpiece, adapted to weld studs with different dimensions, changing continuously, using an automatic stud-welding device, the device being mechanically fed studs in a stud holder, individually and in the correct position, and the stud holder being held by the stud-welding device, guided to the welding position, and the stud is welded to the workpiece, after which the stud-welding device returns the stud holder to the transfer position, in order to take on another stud and to achieve such several stud holders are assigned to the stud-welding device and alternatively connected to the stud-welding device in accordance with a selectable call-up program, so that a given stud-holder, equipped with a stud and connected to the stud-welding device, is separated from the stud-welding device after the weld has been performed thereon and the transfer position has been reached and held in that location, the operating sequence being controlled electrically or electroni

Abstract: A method and apparatus for improved percussive arc welding is disclosed. In this technique a test arc of a voltage no greater than the initiating voltage of the percussive arc welding is first applied across the pieces to be welded. The welding cycle is then performed if, and only if, an arc is detected responsive to the impressing of the test voltage.

Abstract: A stud arrangement on casehardened studded chains for motor vehicles, wherein the studs consist of a steel body which is permanently welded to a chain link and provided with a centrally disposed hard metal pin. The hard metal pin is inserted into the steel body such that it is covered on all sides by steel material of a thickness which at least corresponds to the casehardening penetration depth. In a method for producing such studded chains, an inwardly converging blind hole is cut out from one end of the steel body. The hard metal pin, of a shape corresponding to the conical hole, is forced into the hole, the pin being shorter than the blind hole so that a skirt is formed outside the pin. The edge of the skirt is beveled, and the steel body with the metal pin therein is joined to the chain by resistance welding in a machine for welding studs onto chain links, the body with the pin being moved gradually toward the chain link as the beveled edge melts and flows radially outwards.

Abstract: A composite article having particular utility as a welding stud and a process for producing the article. The article is comprised of a pin and an enclosing member formed from a dissimilar material. The pin is comprised of a head and a shank. The pin is formed from a metal. The cross-section of the head is larger than that of the shank in a direction normal to the length of the pin. The enclosing member fits over and is adhered to the shank. The enclosing member is formed from material in powder form. It is placed upon the shank and sintered thereon. The enclosing member fits up against the head so that the article is substantially devoid of a gap therebetween. The absence of a gap is attributable to the shape of the shank. The cross-section of the shank is larger, in a direction normal to the length of the pin, adjacent the head than over other parts thereof.

Abstract: The invention relates to a tube with surface-enlarging elements attached to the inside thereof, which elements are in the form of radially inwardly directed pins welded on the tube wall. A method for forming such a tube also is provided, the method comprising inserting a holder for each pin into the tube and moving the holder outwardly to press the pin against the tube wall while welding the pin thereto.

Abstract: A fastener is provided for securing an article to a support without making a hole in the support and wherein access can be gained to only one side of the support. The fastener is welded to the accessible surface of the support and the article is clamped to the support by setting the fastener with a blind-riveting tool.

Abstract: Method and apparatus for simultaneously welding by the stud end welding technique a stud having two or more ends. The stud includes at least one elongated relatively thin metallic projection from each end of the stud to be welded. The method and apparatus maintains a current density in a given projection sufficient to disintegrate only a portion of each projection with consequent arc initiation upon contact with the base metal such that the disintegration of a given projection will permit the remaining projections to contact the base metal causing a short to extinguish the one arc which has been initiated and consequent disintegration and arcing of the next tip to strike the workpiece which procedure proceeds randomly from tip to tip until the ends of the stud reach the molten metal pools.