GB1188027A - A Method of Arc Welding with Alternating Current. - Google Patents

Abstract

1,188,027. Welding by fusion. ORDENA TRUDOVOGO KRASNOGO ZNAMENI INSTITUT ELEKTROSVARKI IMENI E.O. PATONA. 28 June, 1967, No. 29747/67. Heading B3R. [Also in Division H2] A method of alternating current arc welding comprises the superimposition of pulses of current B of the same polarity as the arc current at the ends of the half cycles A of the arc current i. If desired the pulses of current are superimposed on the negative half waves of the arc current; furthermore, additional current pulses may be superimposed on the arc current either at the beginning or at the middle of the half waves or both. Thus the stability of the arc is enhanced and the transfer of metal controlled. Arc current to an electrode 5 and workpiece 6 is provided from an A.C. source 1 by way of a transformer 3 and a variable inductor 4. Current pulses are provided by a circuit which includes a capacitor 10 charged by way of a diode 9 from the secondary winding 14 of a transformer 8. The pulses superimposed on the arc current are provided by discharging the capacitor 10 across the arc 7, the discharge being effected by triggering a controlled rectifier 11 at the appropriate time or times, the triggering impulses being provided by a phase shifting circuit which includes the components 15-22. A switch 23 is provided to disable the phase shifting circuit. The welding may be automatic or semiautomatic using consumable or non-consumable electrodes. Shielding gas may include argon (e.g. for stainless steel) and carbon dioxide.