Abstract: Work pieces to be joined together by the flash butt welding method are brought together at a preset no-load voltage, the end faces of the work pieces are fused, and an upsetting is accomplished. The amount of the upsetting is determined within from 1.2 to 3.0 of the amount of the maximum gap between the end faces of the work pieces being welded together, which gap forms in the course of fusing the end faces of the work pieces. The maximum gap is determined from the following relation:.DELTA..sub.max =f(U.sub.o,.delta.),where:.DELTA..sub.max =maximum gap;U.sub.o =no-load voltage;.delta.=thickness of the work pieces being welded together.Empirical formulas to determine the maximum gap for work pieces of various thicknesses are presented.

Abstract: In accordance with the disclosure, the workpieces being welded are brought together by rectilinearly oscillating at least one of them along the line of bringing them together with the amplitude in the movement of the workpiece towards the other workpiece greater than that in the movement of the same workpiece in the direction opposite to the direction towards the other workpiece, voltage is applied to said workpieces for flashing and heating them in the course of bringing them together, and then an upset force is applied to the workpieces. The hydraulic drive adapted to generate the oscillatory rectilinear motion in a continuous flash butt-welding machine includes a hydraulic cylinder with two chambers which provides for moving one of the workpieces being welded with respect to the other and comprises apparatus for feeding hydraulic fluid alternately into either of the chambers of the hydraulic cylinder of the machine, the apparatus being connected with the cylinder through two hydraulic lines.

Abstract: Methods and apparatus for the welding and heat treating of metal parts in which an electric arc extends between a pair of adjacent metal parts or between an electrode and one or more metal parts with the arc traversing the metal part or parts a plurality of times during the heating cycle. For finite length metal parts, i.e. when the surface or surfaces to be heated do not provide closed paths to be followed by the arc, the arc is initiated, caused to follow the surface, extinguished and then reinitiated, or is caused to traverse the surfaces in alternately opposite directions after initiation. With finite length metal parts, run-off tabs are provided at the ends of the surfaces to prevent overheating at such ends. A magnetic field causes the arc to traverse the surfaces and may be modified in strength or distribution to vary traverse rate.

Abstract: In arc butt welding the arc is moved between the faces of the parts to be joined by a magnetic field. In order to insure the arc travels over the whole of the faces to be welded the parts are moved generally parallel to the faces so that the overlapping area of the faces changes during the arc heating.

Abstract: A flash and upset material formed in a flash welding operation can be removed by a machining of the flash and upset material for a short time after the welding operation by providing a workpiece clamping function by a main clamp and providing a welding current feeding function by an electrode table. The main clamp is heavy whereas the electrode table is light so as to be easily movable, whereby the electrode table in the light weight can be backwardly shifted for a short time after the welding operation and a space for inserting a tool holder equipping with a tool for machining a flash and upset material, is formed near the welded line. Since the flash and upset material can be machined during the time maintaining the softness of the flash and upset material at relatively high temperature for a short time, the machining can be attained by only pair of tools.

Abstract: A method for flash butt welding of annular workpieces, particularly chain links, in which the ends of the workpiece to be welded together, are preheated before flashing and upsetting by controlling the feeding force for the upsetting slide in several successive preheat time cycles. The feeding force during the first preheat time cycle is minimized during the first preheat time cycle and progressively increased during advancing preheat time cycles, dependent on the increase in force required for workpiece deformation. The feeding force may have a decreasing increment during advancing preheat time cycles. The feeding force may also have a stepwise increase per preheat time cycle. The feeding force may, moreover, have a continuous increase.

Abstract: Disclosure is made of a butt welding process, whereby butt ends of articles to be welded together are placed one opposite the other in a chamber containing a shielding medium. The butt ends are then heated until a layer of molten metal is formed on their surfaces, and upset in order to effect their plastic deformation and produce a weld joint. According to the invention, the heating and flashing-off of the butt ends are effected by a low-pressure arc uniformly distributed over the entire butt end surfaces of the articles being welded.

Abstract: A method for controlling flashing speed during resistance butt welding comprises measuring values of current density for at least two joints between parts being welded, converting them into d-c. voltages, detecting a maximum voltage value, comparing it to a preset d-c. voltage, the resultant difference value being used as flashing speed control parameter. An apparatus for carrying out the method comprises electric circuits whose number is equal to the number of joints being welded. Each circuit comprises a welding transformer and a circuit for conversion of flashing current density into d-c. voltage. A maximum signal detector comprises circuits for conversion of current density into d-c. voltages, whose number is equal to the number of joints being welded. The detector output is connected to the circuit for comparing a current voltage value to the preset one.

Abstract: A method and apparatus for monitoring parameters which control the quality of welds made by the rotating arc method. Total electrical energy delivered to the parts being welded is controlled and its analog divided by the time during which this energy was applied to obtain average rate of energy delivered. Total mechanical work done on parts being welded and the mechanical relative displacement of machine platens is measured and work analog is divided electronically by the displacement analog to determine average mechanical work per unit of displacement. The two averages thus obtained are compared to preset levels of average electrical energy and mechanical work which have been established empirically. Indicators warn the operator of any variation from the norm. Separate indications and comparisons are also made of each of the parameters.