Showing papers on "Heat-affected zone published in 1971"

Apparatus for controlling electric welding processes

Abstract: An apparatus for controlling electric welding processes with consumable electrodes by generating electric pulses of the variation in the welding parameters, the voltage, current or mechanical vibration, in the workpiece. These variations which are characteristic for the melting during welding are picked up, transformed and supplied to a signaling device to furnish a statement on the transfer of the material which the welder uses to correctly guide the electrode.

Apparatus for vacuum welding of plastics envelopes

Abstract: The specification discloses vacuum packaging apparatus including welding bars, and clamping bars for holding the edges of the packaging envelope before, during, and after the welding operation Preferably the clamping bars may have grooves therein to facilitate escape of air from within the envelope during the evacuation phase A jet of air is blown across the welded edge to cool the weld and facilitate separation of the welded edges from the welding bars

Method for the ultrasonic welding of wires on the metal surface of a support

Abstract: A method of and a device for the ultrasonic welding of wires comprising a non-metal insulating layer on the metal surface of a support by means of a welding tip which is made to vibrate in a direction parallel to the longitudinal direction of a wire to be welded; according to a previously programmed welding cycle, the insulating layer is first removed locally and the wire is then welded; a preceding mechanical or chemical cleaning of the wires is not necessary. The method according to the disclosure provides a welded joint which has compact dimensions and a high mechanical strength.

Method of and apparatus for welding an end plug onto a nuclear fuel element

Abstract: Welding methods and apparatus for bonding a metallic end plug into an end of a metallic fuel tube or rod for a nuclear reactor. Defects in the weld joint between the fuel tube and end plug are substantially reduced by arc welding in a chamber filled with an inert gas, disposing the welding electrode directly over the joint to be welded, deflecting plasma produced during the welding away from the body of the fuel tube, and directing the plasma into the joint.

Self-adaptive welding torch controller

Abstract: A fully automatic, self-adaptive welding system has been provided for programmed welding applications. The welding torch position, either vertically or horizontally, is generally responsive to a signal proportional to the work-to-torch spacing as well as certain other signals including pulses used to control the oscillation of the torch across the weld area. Control of the torch oscillation is, in part, supplied by the spacing signal. Use of the system ensures welds of high quality as to weld tie-in, conformity to vertical or horizontal irregularities in the parts, and thickness.

Electrical system for automatic arc welding

Abstract: A process and system for welding of the tungsten inert gas (TIG) type is described. A welding torch is mounted on a mechanism which provides for motion of the torch with respect to the work (a pipe being welded) in three different directions. Movement in each direction is electronically controlled so as to obtain preset magnitudes of oscillation of the torch, both vertically and laterally with respect to the work. The vertical oscillation is provided by following the pulsating arc current in accordance with a preselected control function. In addition, the system and process provides for control of substantially all of the parameters affecting the formation of the weld in order to produce improved weldments.

Control apparatus for short-circuit arc welding

Abstract: An apparatus for controlling the feeding of the welding electrode in short circuit metal transfer arc welding which employs a feeding speed detecting circuit. The feeding speed varies according to variations in the period of shortcircuiting between the electrode and the workpiece and the time during which a welding arc is generated.

Fatigue crack propagation through weld heat affected zones

Abstract: Fatigue tests were performed on specimens containing weld heat affected zones at two orientations to the stress axis. Two heat affected zones were studied, one in Ducol W30 (a low alloy steel) and the other in mild steel. Under conditions of constant alternating and maximum stress intensity a fatigue crack only propagated at a uniform rate when it was remote from the heat affected zone. A heat affected zone which was harder than either the parent plate or weld metal was found to reduce crack propagation rates by a factor of up to 2 by restricting the plastic zone size around the crack tip. The changes in crack propagation rate could not be related uniquely to the conditions of the material immediately adjacent to the crack tip. Furthermore, the shape of the plastic zone was found to influence the direction of the propagation of a fatigue crack which always deviated toward regions of lower flow stress. A crack was never found to follow the interface between the weld metal and the parent metal heat affected zone because the flow stresses were not the same on either side of the interface. There was no difference in crack propagation mechanism between the parent plate and its heat affected zone for the stress conditions imposed.

Production of an improved non-austenitic steel weld deposit

Abstract: A method of producing an improved non-austenitic steel weld deposit characterized by superior toughness in the Charpy V-notch impact test by melting a covered ferrous low hydrogen arc welding electrode consisting of a current conductive core and a limefluoride coating, which method consists of proportioning the core and coating components containing metallic and oxide forms of the basic metals of the group consisting of lithium, sodium, potassium, cesium, magnesium, calcium, strontium and barium and of the acid metals of the group consisting of aluminum and silicon so that when all components are melted together under the influence of an electric arc they produce a weld metal deposit and a welding slag with a basicity or mole ratio of oxide of basic metal to oxide of acid metal of at least 2.2 and restricting the sources of metallic and oxide forms of titanium in the core and coating components so that the weld metal deposit contains less than 0.07 percent titanium.

Process for welding sheet metal coated with layers

Abstract: A method for the connection of sheet metal panels coated on at least one surface with a layer by the electrical fusion of a metal, wherein the improvement comprises the steps of supplying an electric current for the fusion of metal indirectly along the sheet metal of at least one panel to the zone at which said panels are to be connected to each other, and keeping the temperature of an outer layer of at least one of said panels below the melting point of said layer.

Tungsten inert gas welding control unit with a filler metal feeding means

Abstract: A welding control device for controlling the voltage, current and gas flow rate for a gas tungsten arc welder type welding unit. A motor driven rheostat current decay control is provided to prevent abrupt weld cut-off. The remote console unit comprises a current preset means, a gas control, a voltmeter and ammeter to maintain the voltage and current as well as a filler metal feeding means. The metal filler means is located on and attached to the forward portion of the two button decay control switch.

An Investigation Into the Factors Contributing to Welding of Contact Electrodes in High Vaccum

Abstract: The effect of a vacuum environment on welding of Cu-Bi (0.3%) electrical contacts has been investigated. The experiments have been planned in order to differentiate between the effects of cold welding, diffusion welding and percussion welding. Cold welding has no affect on newly prepared electrodes, but after the electrodes have been arced appreciably a small residual cold weld force is experienced. The diffusion weld strength is strongly dependent upon the contact force, the electrode temperature and the time in contact. The strongest weld forces are measured in the percussion weld experiment where the electrodes experience a high current prestrike arc as they close. It is also found in this study that the weld force decreases rapidly after the electrode faces are exposed to the residual gases in the vacuum. These results are discussed in terms of the chemisorption of residual gases and the real area of electrical contact. The effects of the change in nature of the electrode surfaces are discussed and a satisfactory qualitative explanation of the results is reached.

Method and apparatus for overlaying weld metal which prevents the emission of noxious gases therefrom

Abstract: An inert-gas-shielded submerged arc welding process which prevents emission of noxious gases when overlaying aluminum bronze on a steel base. Apparatus is also disclosed for confining granular flux in the proximity of a welding torch when making an overlay on a cylindrical surface.

Effect of Welding Atmospheres and Welding Polarity on the Nitrogen Content of Weld Metals

Abstract: Mild steel and stainless steel were welded in controlled arc atmospheres.Effect of nitrogen partial pressures in the welding atmospheres of N2, N2-Ar, N2-O2, Air, N2-CO2 or N2-H2 and welding polarity on the nitrogen content of weld metals was systematically studied.The main results obtained are summarized as follows:1. The nitrogen content of weld metals made in neutral or reducing atmospheres such as N2-Ar or N2-H2 increases with the increase of the partial pressure of nitrogen.2. The co-existence of oxidizing gas with N2 in the arc atmosphere increases greatly the nitrogen content of weld metals.3. Anomalous absorption of nitrogen was observed at low pressures of the arc atmospheres.4. The nitrogen content of mild steel weld metals made in N2, N2-Ar, or N2-H2 welding atmospheres is not influenced by welding polarity, while the nitrogen content of stainless steeel weld metals made with DCSP is more than that with DCRP.5. In oxidizing atmospheres such as N2-O2 or N2-CO2, weld metals absorb much more nitrogen with DCRP than with DCSP.

Process and apparatus for submerged arc welding

Abstract: A submerged arc welding process performed on adjacent longitudinal edges of a pipe blank. Two submerged arc welding units are supported on carriages which move on a stationary travel beam over the pipe blank. The welding units start welding at opposite ends of the longitudinal edges and weld toward each other until they meet. At that time one welding unit stops and returns while the second continues forward to overlap the welds while the fused flux remains electrically conductive at the area of overlap. After the second unit merges the welds, it returns.

Phenomena of the Molten Pool at High Current and High Speed MIG Welding

Abstract: The authors have studied the mechanism of bead formation, taking note of the discontinuous bead, particularly "humping bead" at high current and high speed welding. Following facts are clarified.1. In high current and high speed welding, the difference of temperature between the front part and the rear part of the molten pool is much greater than that in ordinary welding and this temperature difference causes strong surface-tension-stream directing from the front to the rear part of the pool resulting in the discontinuity of the bead.2. The authors have investigated some methods to prevent the formation of the discontinuous bead at high speed welding. The basic conceptions are as follows:a. Gravity control of the streamb. Decrease of temperature difference between the front and the rear part of the molten poolc. Decrease of surface tension of the molten poolThese methods aim to repress the strong stream from the front to the rear of the molten pool.For example, by elongating wire extension the arc takes the form of so-called "rotating arc", which heats the molten pool uhconcentratively different from concentrative heating of spray arc and acts to prevent discontinuity of the bead. Fig. 5 shows the critical relation to get continuous bead at high speed welding. This curve is applicable to every diameter of wire.3. The authors analized "melting efficiency" (see equ. 4) of the bead and clarified the relation between "melting efficiency and bead character". The results show that the welding speed at maximum melting efficiency is the limit to form the continuous bead.

Method and apparatus for welding metal sheets

Abstract: In a method of welding relatively thin metal sheets composed at least in part of steel, the steps of electromagnetically holding the sheets which are to be welded while directing to a location on a line where the welding seam is to be situated a welding arc having a hot electrically conductive core and a relatively cold electrically non-conductive sheath, providing relative motion between the sheets and the arc along a line corresponding to the seam, surrounding the arc with a wall of protective gas preventing access of the outer atmosphere to the arc, and providing a magnetic field which deflects the core away from the sheath so that the core impinges upon the line at a location on said line spaced from the location where the sheath impinges upon the line, the core and the sheath both impinging upon the sheets within the wall of protective gas, while providing for the electromagnetic holding a magnetic field which does not interfere with said deflection of the welding arc.

The forge phase of friction welding. I, II

Abstract: Forge phase rigid and plastic region model of friction welding, deriving interfacial dispersion parameter of weld quality optimization

Anti-hygroscopic arc welding coated electrode and the process for producing the same

Abstract: AN ANTI-HYGROSCOPIC ARC WELDING COATED ELECTRODE CONTAINS, AS A BINDER FOR THE COATING MATERIAL OF THE ELECTRODE, A GLASS POWDER HAVING A SOFTENING POINT OF FROM 350* TO 550*C., WHICH MELTS AND COVERS THE GRAINS OF THE COATING MATERIAL, WHEN HEATED TO A TEMPERATURE ABOVE THE SAID SOFTENING POOOINT, SO AS TO FORM VITREOUS FILMS THEREAROUND.

Process for welding metal coated sheet structures

Abstract: This invention is directed to a method of and apparatus for linearly and/or spot welding metal plates that have either clad, coated or oxidized surfaces. In some instances only the exposed surface coatings are removed from the zone to be welded to bare the underlying metal, after which welding is effected and, if necessary, the exposed welded zones are reclad or recoated with the same type of material as was originally removed. Where relatively thick plates are to be welded, sufficient material is removed from at least one of them to define a remaining thin web in or along the zone of welding that can be displaced or forced into linear contact with an adjacent area as an incident to welding, after which the exposed welded zone is reclad or recoated. For spot welding the plates may be bored or drilled at predetermined intervals to receive and retain sets of weldable inserts which become welded together and to the surrounding metal. Recoating or reclading of the exposed welded zones may be effected either by applying molten metal to the surface to be coated, or by wiping pre-heated metal against such surface, or by electrolytic deposition. The method is especially effective with zinc or tin coated or clad iron or steel sheets or plates and with aluminum sheets or plates having oxidized faces.

Resistance welding of aluminum

Abstract: Resistance welding such as spot welding of aluminum sheets and the like is greatly enhanced by the provision of a reacted silicate coating which substantially extends the useful life of welding electrodes by reducing pickup of aluminum on the electrode.

Method for rotary bi-axle type friction welding

Abstract: This disclosure relates to a method and apparatus for friction welding wherein an improved friction welding of a first and a second workpieces are carried out in a manner such that welded and plasticized workpieces are rapidly synchronized and also a larger thrust is provided at only the end stage of the welding so that change of metallic structure of welded workpieces due to cooling which tends to cause cracks in the welded portion is prevented. In order to carry out this improved friction welding, the apparatus for friction welding includes a second driving means for driving the second workpiece, detecting means for detecting the sum of the lengths of welded workpieces capable of providing a signal for interrupting the drive of the first workpiece and hydraulic systems capable of adjusting the thrust according to a signal from the detecting means.

Apparatus for welding corrugated materials by plasma electron beam welding system

Abstract: A method and apparatus for achieving electron beam or plasma electron beam welding of corrugated panels utilizing a particular vacuum chamber arrangement that encompasses only a small portion of the workpieces. This chamber is formed by the part being welded and a relatively soft rubber belt molded to fit the contour of the corrugations and formed of two interlocking havles. The interlocked lips of the belt and the configuration of the shell portion of the welding chamber is such that the belt seal opens and closes allowing passage of the welding head along its length while maintaining the vacuum seal.

Method for making a friction welded article

Abstract: First and second metal components to be joined at opposed interface surfaces by friction welding, the first component having greater hot strength than the second component, are friction welded by first shaping the interface surface of the first higher hot strength component prior to friction welding so that initial contact during friction welding is at the peripheral areas of the contacting surfaces. In one form, such shaped surface is in the form of a depression concave into the first component. The walls of the depression are disposed at an angle in the range of about 1* - 10* in respect to a plane normal to the friction welding axis of rotation.

Method of manufacturing large rotatable members by welding

Abstract: A method of producing large rotatable steel parts with circular cross-sections for construction of large machines such as shafts of generators and turbines. In a first stage a welding process is effected under a welding head for production of a weld connection in the central region of a welding gap between the parts. This central weld is subsequently circularly machined and the remaining peripheral groove is widened and formed of V shape. The parts are then welded at the groove, while the parts are rotated, by use of a welding process with a granulated welding flux.

Means and technique for removing flux on a welding rod

Abstract: The re-fused flux on the tip of a welding rod, is removed by striking the tip against an abrasive surface defined by a strikeplate on the overside of one of the welder''s gloves.

Arc welding flux

Abstract: A WELDING FLUX WHICH COMBINES THE ADVANTAGE OF EXCELLENT SLAG REMOVAL IN MULTIPLE PASS DEEP GROVE WELDING AND IS "NEUTRAL" IN THAT THE WELD METAL ANALYSIS IS RELATIVELY UNAFFECTED BY CHANGES IN ARC VOLTAGE.

Weld support for welding apparatus

Abstract: A weld support for a gas shielded metal arc welding apparatus is disclosed as having a welding block provided with a relatively flat surface, a resilient rubber strip around the periphery of the flat surface, a welding chamber within the block and a plurality of gas exhaust passages connecting the welding chamber and the exterior of the block and having bends intermediate their extremities. A shielding chamber is affixed to the welding block around an opening into the welding chamber for receiving and holding a nozzle of the welding apparatus perpendicular to the flat surface of the welding block and enclosing shielding gas fed through the nozzle into the welding chamber. When a weld is being made, the welding block is held against the material being welded to maintain the welding apparatus perpendicular to the material. The rubber strip assists in maintaining this perpendicularity by accommodating any irregularities in the surface of the material. The rubber strip also prevents flow of molten weld material away from the vicinity of the weld spot. The bend in the gas exhaust passages prevent weld spatter from escaping from the welding chamber.