Showing papers on "Arc welding published in 1975"

Welding control systems

Abstract: An electric arc welding system includes programming circuits for controlling the position of a welding torch on a carriage wherein the carriage is caused to move along in the direction of a weld path on a member to be welded. The programming circuits cause the torch to move back and forth across the weld path as the carriage moves parallel to the weld path, the excursion time of the torch and dwell time of the torch on either side of the path at the limits of its excursion constituting the selected position program. The torch thus follows a repetitive generally truncated sawtooth pattern. The welding current to the torch is connected into the programming circuits to be responsive to a selected program so that the level of current provided during the dwell times is different from the level of current provided during the excursion times. Additionally, the speed of wire feed for the torch can be made responsive to a selected position program so that the speed wire is fed is different during the dwell times from the speed wire is fed during the excursion times. Torch centering and arc voltage controls are included, the overall system functioning to provide welds of greatly improved quality.

Short-circuit arc welding with constant beads

Abstract: In short circuit arc welding there are many parameters which influence the automatically controlled welding procedure, but which frequently may affect the quality of the weld. In some circumstances the welding bead which is formed does not flow in to the molten pool of the workpiece, but disintegrates into many small drops around the weld owing to an excessive short-circuit current. The invention proposes methods and arrangements in which certain parameters, such as arc time and a short-circuit current delay time are controlled or maintained constant, so that always a constant bead size is assured owing to a constant power, after which said bead of constant size is first partly introduced into the molten pool and subsequently the short-circuit current for separation is applied.

Remote control for an arc welding machine

Abstract: The control unit comprises an elongated body having a forward torch mounting portion. Rearwards of the torch the body houses a linear potentiometer which includes an upstanding control arm for its movable contact. An off-on switch is located within said body, in a position to be contacted and operated by the control arm. A thumb button controlled sliding control member is attached to the control arm. In use, the user grips the mid portion of the body and places his thumb on the thumb button. He uses a simple linear movement of his thumb to both control the linear potentiometer, for varying the welding current, and to operate the off-on switch, for turning the arc welding machine on and off.

Arc welding method and arc welding apparatus

Abstract: This invention provides arc welding methods and arc welding apparatus which weld materials by giving a plastic deformation of definite curvature to wire itself in a process before supplying the wire to a welding nozzle, restoring the wire delivered from the welding nozzle to the plastic deformation of definite curvature, delivering rotatively the end of the wire in a definite period from a delivery hole of the welding nozzle in butt welding of thick board, especially narrow gap welding.

Fume extraction control for welding gun

Abstract: A welding gun is provided having vacuum fume extraction means wherein the level of vacuum exerted at the arc welding zone is regulated to avoid extracting shielding gas supplied to the welding zone. The vacuum level is regulated by admitting sufficient air to a fume extracting passage provided within the gun to reduce the vacuum to the desired level.

Method of large current gas shielded arc welding

Abstract: A method of large current gas shielded arc welding wherein the welding is accomplished at high speed by a single electrode or tandem sequence electrodes in an atmosphere of a mixed shielding gas comprising essentially of an inert gas with an addition of less than 30% of carbon dioxide gas or less than 5% of oxygen and supplied at an overall flow rate of 50 to 200 l/min by using large diameter solid wire consumable electrodes of low alloy steel material with a diameter of 3.0 to 6.4 mm φ under the following conditions: welding speed 300 to 1500 mm/min; welding current, 600 to 1500 amp; and arc voltage, 23 to 36 volts. With this method, the welding of steel can be accomplished at high speeds with a reduced heat input and an improved efficiency and it is particularly well suited for the welding of open tubes for very low temperature line pipe which must retain a high degree of toughness at very low temperatures.

Method and apparatus for shortcircuiting arc welding

Abstract: A method and apparatus for controlling the welding current in shortcircuit transfer arc welding including a method and control apparatus for maintaining the effective value of the welding current during arcing period at a predetermined value. Maintenance of the effective value of welding current during arcing period is necessary to keep the size of a fusion zone and the depth of penetration constant throughout welding operation.

Method of manufacturing thick, high-strength steel pipe for low temperature service

Abstract: A method of manufacturing a thick, high-strength steel pipe for low temperature service comprising the steps of forming into tubular shape a steel plate having a thickness of over 12 mm and a specific composition, of which the C eq value is adjusted to less than 0.50, when the Mn content is less than 1.0 % whereas the C eq value is adjusted to less than 0.45 when the Mn content is over 1.0 % and less than 2.0 %, and nextly of welding said tube form at high speeds and high efficiency by the process of single electrode or multiple electrode large-current gas-shielded arc welding with one pass per electrode on each side of the seam at a specific condition, each electrode preferably consisting of a solid wire essentially containing less than 0.3 % Ti with or without the addition of less than 0.01 % B, and said steel pipe having, in its as-welded condition, mechanical properties such that the yield point of the base metal portion is over 60,000 psi and the weld zone has a maximum hardness of less than Hv10-280 and a Charpy test absorbed energy of over 7 Kg.m at -10° F. Even when the C eq value of said steel plate is less than 0.65, a thick, high-strength steel pipe for low temperature service having equal mechanical properties to the above mentioned pipe may be manufactured, after welding, by subjecting the welded pipe to a post heat treatment in which the welded pipe is held at a temperature between 500° and 700° C for less than 1 hour.

Cored wire junction

Abstract: Ductile junction of metal-sheathed composite wire, such as flux-cored welding wire for use in automatic arc welding machines, is provided by process comprising resistance upset welding

Power supply for electric arc welding

Abstract: An arc welding power supply of the type which employs a saturable reactor circuit to control the supply power from an alternating current source to the welding electrode. A control circuit varies the current through the control winding of the saturable reactor to provide the desired welding current. An additional circuit monitors the welding current and disables the saturable reactor control circuit when the welding current drops below a low threshold value, thus reducing the open circuit voltage between the welding electrode and workpiece and minimizing the danger of electric shock to the welder while changing electrodes. The saturable reactor is connected in series with the primary winding of a transformer which also serves as the output winding of the saturable reactor.

Method of multiple electrode gas shielded arc welding

Abstract: of the Disclosure In a multiple electode gas shielded arc welding method wherein a plurality of electrodes are arranged along the welding seam line of a piece of metal to be welded and the continuous gas shielded arc welding of the piece is accomplished simultaneously by the electrodes, the chemical composition of a mixed shielding gas fed to the electrodes is selected in such a manner that the chemical composition of the shielding gas fed to the leading electrode or electrode group differs relative to that fed to the trailing electrode or electrode group to have a different active gas volume ratio and in this way the chemical composition of the weld metal layers formed by the preceeding and following welding operations are homogenizing to ensure uniformity of the properties at every positions in the weld zone.

Bare electrode for welding of low temperature steel

Abstract: A bare welding electrode of a diameter of at least 3.0 mm for use in a large current gas shielded arc welding process in which steel for low temperature use is welded by a welding current of at least 500 A in a shielding gas composed mainly of an inert gas such as Ar, He or the like. In one aspect the electrode comprises up to 0.12% C, up to 0.8% Si, up to 3.0% Mn up to 0.25% Ti, at least one member selected from the group consisting of up to 4.0% Ni, up to 0.8% Cr and up to 1.0% Mo and the carbon equivalent (Ceq), of said electrode being up to 0.60% which is represented by the formula Ceq = C + 1/6Mn + 1/24Si + 1/40Ni + 1/5Cr + 1/4 Mo wherein each element denotes the content, % by weight of the element. In the second aspect the bare welding electrode comprises up to 0.12% C, up to 0.8% Si, up to 3.0% Mn, up to 0.19% Ti, 0.0005 to 0.015% B, at least one member selected from the group consisting of up to 4.0% Ni, up to 0.8% Cr and up to 1.0% Mo and which a carbon equivalent of up to 0.60%, calculated according to the above formula.

D.C. arc welder with solid state components

Abstract: A D.C. arc welder with solid state components which is provided with means for converting A.C. to D.C. and with controlled diodes serially connected in the D.C. line between the converting bridge and a transformer providing electric insulation between the D.C. line and the terminals of a welding head. A further controlled diode is also connected to the D.C. line downstream of the control diodes and in parallel with the transformer and in series with a capacitor. Between the transformer and the welding head a rectifying assembly is arranged. The serially connected controlled diodes are simultaneously triggered by a pulse amplifier and transformer. A further pulse amplifier and a further pulse transformer subsequently trigger the further controlled diode, whereby the serially connected controlled diodes are turned off. The pulse amplifiers and transformers are alternately driven by a square wave generating assembly whose period depends on a magnitude proportional to the voltage and current levels at the terminals of the welding head.

Method of joining a copper contact button to the aluminum headbar of an electrode plate

Abstract: A method of joining a copper contact button to the aluminum headbar of an electrode plate used in the electrolytic industry for the recovery of nonferrous metals. The method consists in the steps of coating the copper contact button with a thin layer of silver, mechanically threading the copper contact button into the aluminum headbar, preheating the assembled copper contact button and aluminum headbar to a temperature ranging from 200° to 900° F, and welding the coated copper contact button to the preheated aluminum headbar. When arc welding, preheating in the temperature range 375° to 475° F prevents oxygen from the copper diffusing into the weld.

Stud welding gun and method of operation

Abstract: A welding terminal operable to arc weld to a work piece a stud thereafter drive an element prethreaded to the stud. In one embodiment, the welding terminal may be adapted to cooperate with a guide to facilitate engagement with the prethreaded element, and in another embodiment, the welding terminal may have fluting or ribs to grippingly engage a portion of the prethreaded element. The duration of the arc weld and the sequencing of the welding and driving functions both may be automatically controlled. The normal force imposed on the fixed stud portion and the torque imposed on the movable threaded portion may be substantially automatically limited.

Orbital welding apparatus

Abstract: Orbital welding apparatus in which wire is fed to the welding zone by wire feed mechanism operable by differential rotation of two drive members operable at different speeds, one member carrying a welding electrode and the wire feed mechanism. Both drive members have openings allowing entry of tube to be welded. The drive members cooperate with auxiliary drive members which fit into the respective openings in the main drive members. The auxiliary drive members are guided across an opening in a housing enclosing the drive members by means of a bridge piece securable to the housing across the opening. The apparatus permits orbital welding of very closely spaced tubes without using a wire feed drive motor mounted on the rotatable assembly. Both TIG or MIG arc welding methods may be performed by the invention, or any method involving the feeding of wire into the weld zone.

Orbital welding apparatus

Abstract: Orbital welding apparatus in which wire is fed to the welding zone by wire feed mechanism operable by differential rotation of two one-piece U-shape drive members operable at different speeds, one member carrying a welding electrode and the wire feed mechanism.Both drive members have openings allowing entry of tube to be welded. The apparatus permits orbital welding of very closely spaced tubes without using a wire feed drive motor mounted on the rotatable assembly. Both TIG or MIG arc welding methods may be performed by the invention, or any method involving the feeding of wire into the weld zone. -

Method for specifying hot isostatic pressure welding parameters

Abstract: A procedure for graphically presenting the minimum pressure and temperature required for hot isostatic pressure welding of metals and alloys is described. The use of one such graph for specifying weld parameters is demonstrated and is found to be reasonably accurate. (auth)

Environmentally protected arc welding apparatus of the forced ventilation type

Abstract: A compact and portable arc welding apparatus of the transformer reactor type having a main compartment cooled by forced ventilation and a side compartment sealed from hostile environment, the two compartments being part of a common housing which can be stacked on another similar equipped housing of an arc welding apparatus.

Arc welding machine

Abstract: An arc welding machine having a strap sliding to advance with advance of the welding position, wherein an electric conductor is disposed on the strap at a position not facing a welding groove with the electric conductor being insulated from the strap, and electric current being applied to the electric conductor while it is being cooled by water, to thereby control the arc direction.

Flanged stud for arc welding onto metal base - where flange has progressively decreasing diameters which control arc

Abstract: At least three flange sections with different dias. are pre. employed with contours which blend into the adjacent sections in some cases; and the dia. of the end of the flange adjacent to the joint surface is pref. slightly larger than the shank dia. A good weld is obtd. even when the optimum welding parameters are not employed, i.e. the most suitable electric current and arc welding time.

Fixing a plastics foil to a base, using plastics mounting pieces - by welding the former to the latter at a selective sealing strength

Abstract: Fixing a plastics foil to a base comprises fastening mounting pieces which are pref. of plastics, advantageously of the same plastics as the foil, to the base. The foil is then laid over, and welded to them. The weld strength between mounting pieces and foil is controlled so that it is smaller than the tear strength of the foil. The process is used esp. for the fixing of sealing foils in tunnel construction. The tear strength of the foil is about (pref. 2.5) times the seal strength. The welding of foil to the mounting pieces is achieved by hot air or by electric welding.

Guide tube for an arc welding gun

Abstract: Guide tube for an arc welding gun. The normal threaded connection between the guide tube in an arc welding gun and the holder for same has been improved for the purposes of electrical transmission by utilizing tapered threading for same. Particularly it has been found that the electrical conductivity through said parts is substantially improved if such conical threading is of such design that the conicity of the thread is at a ratio of 1:16 ± 20 percent.