Showing papers on "Electric resistance welding published in 1976"

Electric arc welding processes and apparatus therefor

Abstract: There is provided a method and apparatus for electric-arc welding, in which an alternating current of positive and negative pulses is supplied to produce an electric arc between a welding electrode and a workpiece. The ratio of the durations of the positive and negative pulses of welding current is arranged to be changed in response to a signal from a sensing device adapted to sense a change in a characteristic of the electric arc so as to provide optimum welding current for changed welding conditions. The ratio of the amplitudes of the positive and negative pulses may also be varied in response to a signal from a sensing means.

Apparatus and method for weld bonding

Abstract: Improved apparatus for weld bonding together a pair of conductors separated by a layer of thermo-plastic insulation material. The apparatus comprises a pair of welding electrodes for urging the pair of conductors together at a first level of electrode squeeze pressure while a first low level of current flows through the electrodes and conductors until the thermo-insulation material between the conductors beneath the electrodes is penetrated, electronic circuits for sensing this insulation penetration and initiating after a pre-selected time delay, a second higher level of welding current and electronic controls for increasing the electrode squeeze pressure from the first level to a second higher or forging level for at least a portion of the flow of the second higher welding level of current. A method for forming the weld bond is included.

Maraging stainless steel welding electrode

Abstract: Nickel-chromium-silicon steel electrode for arc welding provides maraging stainless steel weld deposits having desirable strength, toughness and corrosion resistance in age-hardened condition. Electrode arc can be shielded with inert gas or with lime-cryolite-titania flux containing specially controlled proportions of manganese.

Review of the present state-of-the-art in explosive welding

Abstract: A brief review of the history and simplified mechanism of explosive welding is presented. Consideration is then given to the present state of understanding of the parameters which control the explosive-welding process, and the implications of these parameters in relation to thin- and thick-plate cladding. The problem of cladding large thick plate is then considered and experimental data are reported which support the welding parameters proposed, and which allow definite conclusions to be drawn of the set-up required to achieve welding over the whole plate and close to the edges of the parent plate. Applications of explosive welding to cylindrical surfaces are reported including tube-to-tube welding, plugging of heat exchangers, welding of collars to tubes, etc. In particular, the problem of ligament distortion in tube-to-tubeplate welding and plugging is considered. The alternative possibility of placing bungs in the holes adjoining that in which a tube is being welded is examined. Other applicati...

Diffusion welding method

Abstract: PURPOSE: To average pressure distributions and make possible even bonding by beforehand providing the reinforcements of weld of inverted taper form having the bottom width and height of the specified size and shape to a pressure plate in performing diffusion welding of joint type. CONSTITUTION: For example, in the case of vacuum-diffusion-welding the lower plate 1 and blades 2 of upper plate 3 of a centrifugal compressor impeller, the pressure plate (corresponds to blade 2) is beforehand formed to have the reinforcement of weld 2' of inverted taper form of the bottom width W 0.2W0.4t with respect to the thickness t of the pressure plate 2 and height H 0.4W0.6t with respect to the thickness t of the pressure plate, by which the face pressure distributions of the pressing force P acting upon the contact surface 4 of the blades 2 and lower plate 1 are averaged as compared to conventional methods. As a result of this, the bulging deformation of the blades 2 and the formation of sharp edges do not occur, and the blades are evenly bonded, resulting in higher use perfomance of the weldment. COPYRIGHT: (C)1980,JPO&Japio

Ultrasonic testing method and apparatus for resistance welding

Abstract: An ultrasonic vibrator disposed on one of two opposed electrodes having two metallic plates sandwiched between them for being welded intermittently delivers a pulse-shaped ultrasonic wave to a reflecting surface located in the other electrode and receives the wave reflected from the reflecting surface. The vibrator converts the received wave to an electrical signal that is applied to a minimum sensor and a peak sensor. The minimum sensor senses and holds the minimum peak magnitude of the signal which is then subtracted from the peak magnitude of a similar signal developed within the peak sensor at the time of termination of the welding current. The resulting difference between the two magnitudes determines the weld condition of the welded plates.

Method and an apparatus for automatic electric welding

Abstract: When carrying out electric fusion welding with at least two current-carrying electrodes, these electrodes are held in a joint holder in non-parallel positions so that they meet in a point of intersection in which melting of the electrode material takes place. Hereby the risk of burn-through is minimized and an additional degree of freedom which can be used for controlling purposes is obtained.

Flash welding apparatus and method

Abstract: Improved apparatus and method for performing flash welding is disclosed. The apparatus moves adjacent surfaces of workpieces toward each other and applies electrical energy between them for flash heating the surfaces in a flashing step, after which it forces the surfaces together in an upsetting step, while continuing the application of the electrical energy for a predetermined time. Apparatus is provided for calculating and monitoring the amount of electrical energy applied to the workpieces during welding, along with control circuitry, for limiting the amount of electrical energy applied during the upset step to a predetermined function of that applied during the flashing step. An energy recorder produces an indication of the amount of electrical energy applied to the workpieces during welding.

New process combines plasma with gma welding

Abstract: A process of gas metal-arc welding in a thermally ionized gas is described in which the filler metal is fed along the axis of a plasma stream to the workpiece Two of the most important electrode arrangements that can be employed with this process are discussed The electrical properties and the flexibility of gas metal-arc and plasma-GMA welding are compared Data on deposition rate, welding, speed, penetration and wetting-in are determined Finally, a number of possible applications and some already achieved are described

Overhead submerged arc welding process

Abstract: The present disclosure relates to an overhead submerged arc welding process wherein a flux for the submerged arc welding is supplied from the underside of the welding line while at the same time a consumable electrode is supplied from the underside of the welding line, the process being characterized by maintaining the interrelationship between a flux supply cylinder and the plates to be welded such that the length from the under surfaces of the plates to be welded to the upper end of the open flux supply cylinder and the diameter D of the opening at the end of the flux supply cylinder is represented by the formula 2≦D/I≦15.

Bimetal resistance welding electrode and method for making

Abstract: A bimetal resistive welding electrode having a dispersion strengthened copper tip portion and a shank portion formed of a high conductivity copper is produced by brazing together a conductive copper billet and a dispersion strengthened copper billet to form an extrusion blank. The brazing temperature is such that the dispersion strengthened copper is not annealed. The extrusion blank is then extruded into the shape of a welding electrode with the extruding process hardening the conductive copper shank portion to produce a full hard electrode.

Friction welding method and apparatus

Abstract: A friction welding method and apparatus which monitors temperatures at the interface of ferrous and nonferrous metal products being welded and provides controls for insuring satisfactory welds and also provides automatic means of verification thereof as well as rejection of unsatisfactory welds. Light-sensing means is utilized to detect acceptable welding temperatures at the weld interface for initiating and controlling the welding or forging interval and application of forging pressures. Visible signal means is provided for indicating a faulty weld and mandatory operation of manual means is required for release of faulty welds. Automatic controls in the form of fluid pressure logic circuitry provides necessary interlocks and sequences of operation.

Electrical contact element and method of producing the same

Abstract: The contact element is produced by ultrasonic welding one or more contact pieces onto a carrier, an intermediate layer in the form of a metal powder, for example aluminium, being interposed between the contact piece and the carrier prior to such welding in order to assist in the welding of contact pieces made of material which would otherwise be difficult to weld.

Machine for welding aluminum to aluminum

Abstract: A method of welding aluminum to aluminum by thermal resistance welding, providing good electrical and mechanical characteristics. The method uses special electrodes for thermal heat that are hard and have a high electrical resistance, such as molybdenum or tungsten alloy and also relies on the aluminum oxide coating on the aluminum to provide the desired resistance heating of the aluminum to cause welding of the aluminum material. The machine disclosed provides a means for securing aluminum leads to the start and finish end of an aluminum winding automatically and simultaneously.

Low hydrogen welding electrodes

Abstract: An improved welding electrode for producing weld metal having low amounts of hydrogen therein so that hydrogen-assisted cracking in the weld zone is minimized. This is especially beneficial for welding high strength steels having tensile strengths of about 70,000 psi and above. The electrode has a filler wire core and a flux covering of predetermined constituents and low moisture levels such as below about 0.6 percent. The flux is bound together with a binder of hydrolyzed organic silicate (silica) which makes no substantial contribution to the moisture level of the covering and which also makes the covering resistant to hygroscopic moisture pickup before the electrode is used for welding. Thus, this binder minimizes the amount of hydrogen from any moisture in the covering which may be introduced into the weld metal during welding. Additionally, the flux covering contains a source of barium or cesium in an amount effective to reduce the slag/metal reaction temperature during welding. By so reducing this temperature, the amount of hydrogen actually introduced into the weld metal from the electrode covering and binder is minimized. This reduction of the slag/metal reaction temperature during welding has been found to have the additional advantage of reducing the amount of oxygen in the weld metal. This provides increased impact properties for the weld metal.

Welding of laminations of core-plated silicon steel

Abstract: The disclosure is directed to apparatus for and a method of joining a plurality of laminations of electric steel, which are individually core-plated for electrical insulation purposes, to form a laminate structure used in the manufacture of electrical machinery. Joinder of the laminations is accomplished with the laminations in face-to-face relation and arc welding a bead transverse to the stacked lamination edges. To avoid porosity in the weld bead, the arc welding process uses microwire having a diameter of no greater than about 0.050 inches in a moving welding head that maintains the microwire in close proximity to the welding surface. The operating voltage of the arc welding apparatus is controlled to produce an operating welding current of no more than about 170 amperes. The effect of using microwire of such size under such an operating current prevents overheating and degradation of the coreplate, and results in a proper deposition of a strong, non-porous weld bead.

Apparatus for controlling the welding pattern between weldment components

Abstract: An arrangement for actuating welding guns to weld weldment components in a predetermined welding pattern wherein the weldment components are movable relative to the welding guns. Movable means are movable in synchronism at a predetermined reduced speed in relation to the speed of the movable weldment components with means on the movable means corresponding with the desired welding pattern to be formed on the weldment components. Scanner means are electrically connected to the welding guns and are responsive to the indicating means to sequentially activate and deactivate the welding guns to weld the weldment components and form the predetermined welding patterns thereon. Limit switch means are electrically connected to the welding guns and means are provided on the movable means to actuate the limit switch means when the weldment components have completed their movement relative to welding guns to deactivate the welding guns.

Method for pressure welding metal workpieces

Abstract: A method and apparatus for pressure welding together novel aluminum or magnesium workpieces Edges of workpieces to be pressure welded together are aligned with each other by abutment and one workpiece retracted from the other a predetermined distance to define an open channel between the edges The workpiece edges are quickly heated to a temperature within the range of from about 200° to 900° F by passing a uniform flow of heating gases through the channel such that the edge tip and sides of each workpiece are softened while the edge inner cores remain cooler and harder with their mechanical properties unaffected by the heat and the workpieces then moved into abutment with each other to close the channel and immediately pressed together under high pressure for expulsion of softened metal containing deleterious materials such as surface oxides and creation of a solid-phase weld bond between the relatively cool and hard inner cores An air curtain can be provided to improve control of the heating of the workpieces and to enhance pressure welding together of workpieces of different gauges and of different metals, such as welding of aluminum to magnesium alloys

Apparatus for welding studs to workpieces

Abstract: A method and apparatus for welding studs to workpieces are provided. The invention is particularly concerned with welding studs to workpieces made of materials having relatively low electrical resistance but covered with layers of other materials having higher electrical resistance, a common example being metal workpieces having painted surfaces. In order for the stud to make effective electrical contact with the workpiece at the beginning of the welding cycle, the paint must be eliminated; in accordance with the invention, this is accomplished by rotating the stud which effectively removes the portion of the paint in contact with the stud. Electrical contact can then be established between the stud and the workpiece to enable the welding cycle to be initiated.

Machine for welding solar cell connections

Abstract: Machine for welding a connection wire over a solar cell electrode which comprises a base, a welding mount for the solar cell which is supported on the base, means for holding the solar cell on the welding mount, welding electrodes, means to lower the welding electrodes over the solar cell and the connection wire superimposed thereon, means for applying electric current pulses to said welding electrodes, and it is characterized by the fact that it further comprises means for imparting to said mount an alternating transverse movement in relation to said base before and during the welding operation

Method for controlling the shape of a molten pool in gas shield arc welding

Abstract: A method is disclosed in which gas shield arc welding is carried out while applying a gas at a higher pressure than the shield gas to the rear part of the surface of molten metal during welding. By this method, welding proceeds while the molten pool is being maintained in the desirable shape, and the welding can be performed at high currents and speeds without causing bead defects such as undercut formation or humping.

Laser beam welding using small dia beam - provides short welding times without altering props. near the weld

Abstract: In a process for the welding together of two or more materials, each possessing special physical properties, the materials are melted by a laser beam at the desired junction so that the molten zones are mixed together, but the materials outside the junction retain their original physical properties. For welding, one or more elements which are not present in the materials being welded, or only present in a minor amt., may be mixed in the molten zone. To restrict the radial spread of heat, the laser is pref. operated in the transverse TEM. mode, and the molten zone is pref. 0.1mm dia. using operational times of ca. 1 msec. Prevents the formation of zones adjacent to the weld which have different properties to those possessed by the materials being joined, e.g. transition zones. The materials being welded are pref. spring- or magneic-materials, plastics, dielectrics, ceramics, or a combination of SmCO5 with iron. The additional element(s) may improve weldability or weld-strength, or prevent cracking, and are pref. Nb, Ti or Ta when an Fe/Ni or a Cr/Fe/Ni alloy is being welded.

Fabrication of HK-40 in the field

Abstract: Welding of Cr--Ni steel components that have never been in service, the repair welding, and modification of cast components under field conditions are discussed.

Arc time indicating apparatus for stud welding utilizing a capacitive power source

Abstract: Apparatus is provided for measuring and indicating the length of time a welding arc exists in a stud welding cycle utilizing a capacitive power source. Heretofore, the arc time of stud welding apparatus employing capacitors for the power source has only been measured in the laboratory with an oscilloscope. The new indicating and measuring apparatus for the arc time is usable with conventional stud welding, contact stud welding, and gap stud welding employing capacitive power sources. The apparatus produces a number on a visual indicator in the form of a meter or a digital read-out device and the operator can note the number when the ultimate weld is produced. The operator can then subsequently adjust the equipment to repeat that number on the indicator to always be assured of optimum weld quality without the necessity of repeating a number of test welds.

Apparatus for welding articles of thermoplasts

Abstract: The apparatus for welding articles of thermoplasts using additional welding material is provided with a special melting device for the welding material. The melting device comprises a guide channel for the supply and preheating of the welding material, which channel merges into a melting channel of diminishing cross section closed at one end. The melting channel is provided with lateral bores which discharge into a melting chamber of low height in communication with a collecting zone for the plasticized welding material, which collecting zone is connected with the outlet opening of the welding shoe.

Pretreatment for the resistance welding of aluminum

Abstract: This invention relates to a method of pretreating an aluminum surface for the resistance welding thereof wherein an oxide coating is formed on the aluminum surface having a controlled electrical resistance and then the oxidized surface is stabilized by treatment with a hot aqueous alkaline solution containing long chain carboxylic acids.

Parallel Gap Welding to Thick-Film Metallization

Abstract: This study was directed at the parallel gap welding response of a series of gold and platinum-gold thick-film conductor materials which were subjected to various peak temperature/belt speed firing profiles. The parallel gap welding was conducted using a variety of weld voltage/pulse duration settings and a nominal 0.05-mm-thick by 0.38-mm-wide pure gold ribbon. Evaluation of the welds was determined through a 90° peel test. From the resulting data the following conclusions were reached. 1) Parallel gap welding is a viable approach to gold ribbon interconnection to thick film. 2) In general, thicker fired films respond better to parallel gap welding. 3) Sensitivity to firing profile, as reflected by parallel gap weld strength, is a characteristic of each specific thick-film material which must be determined and properly optimized. 4) Sensitivity to weld parameters is a characteristic of each specific material and should be optimized with firing profile. 5) The Pure gold conductor materials are not as satisfactory as platinum-gold conductors for parallel gap welding.