Abstract: A method of flash-butt resistance welding of a batch of like parts in pairs consists in that during flashing off of workpieces (1,2) they are brought apart or together depending on the resulting resistance obtained by comparison of the actual resistance between the workpieces (1,2) being welded with the specific short-circuit impedance of the welding circuit, which is determined during the upsetting of the preceeding pair of workpieces (1,2) after the welding current reaches a constant level.

Abstract: The disclosed process includes the steps of and upsetting the flashing parts being welded. The flashing is conducted with concurrent measurement of useful electric power and an electric parameter of the flashing process which is related to the power by a function which maximizes the useful power at a predetermined value of said electric parameter. Then the value and sign of the power and parameter increments are determined within one and the same period of time. The parts are brought closer together up to the moment when the ratio of the power and parameter increments reverses ints sign. Then the parts begin to be separated up to the moment when the value of said ratio reaches the preset value selected to suit the welding circuit resistance and the cross sectional area of the welded parts.

Abstract: A flash-butt resistance welding process including a flashing of parts being welded and their upsetting. The direction of speed of motion of the parts during flashing is changed by converging and diverging them. The parts being welded are converged up to the moment when the total resistance of elementary contacts arising between the flashed surfaces of the parts becomes equal to 0.4-0.5 of the short-circuit impedance of the welding machine. Then the parts are diverged up to the moment when the summary resistance of elementary contacts reaches 1.4-1.6 of the short-circuit impedance of the welding machine.