Abstract: A method for pressure welding of parts with heating with an arc moving in magnetic field in which the parts (2,3) are placed coaxially with each other with a working gap (.delta.) between their ends magnetic field is created in the gap (67 ) and electric arc (6) is fired to heat the ends of the parts (2,3). A d-c component of voltage of the arc (6) is measured, and when this component reaches its minimum value corresponding to a temperature of the ends of the parts (2,3) at which plastic deformation of the material of the parts can occur, a pulsed increase in the arc current is carried out, with subsequent upsetting of the parts (2,3).

Abstract: A method of controlling relative movement between an ingot and a mold consists of monitoring the level of the metal pool in the mold by measuring the voltage between the ingot and a mold section disposed above the metal pool, in contact with the bath of molten slag and insulated electrically from the ingot and from the ingot-forming mold section; comparing an instantaneous value of said voltage with a predetermined value and varying the relative speed of the ingot and the mold depending on a signal proportional to the difference between the instantaneous and the predetermined values of said voltage so that the predetermined level of the metal pool is restored.