GB1363450A - Mehtod of welding iron steel and non-ferrous alloys - Google Patents

Abstract

1363450 Welding by fusion NIPPON STEEL CORP 13 Oct 1971 [13 Oct 1970 24 Oct 1970 17 Nov 1970 1 Dec 1970 24 March 1971] 47707/71 Heading B3R In consumable electrode wire arc welding of iron, steel or non-ferrous alloys, in any position, wherein to improve weld metal properties the welding current is increased and decreased periodically, wire feed speed is increased and decreased respectively and in synchronism with the current increase and decrease to control arc length, e.g. to maintain the latter constant, and welding torch travel speed is varied in a fixed relationship to the welding current varistor. Further, the electrode wire may be transversely oscillated. The invention may be applied to gas shielded (using solid wire), gas shielded or unshielded (using a tubular flux-cored wire) or submerged arc welding. Current, wire feed and torch travel may be changed by magnetic amplifier, feed motor current and travel motor current control respectively. In Fig. 2a, 2b, 2c, the current i changes between I 1 for a period t L and I 2 for a period t H , the wire feed speed v and torch travel speed are changed, in synchronism, between V 1 and V 2 , and S 1 and S 2 . The periods t L and t H may lie between 0À1 and 3 seconds. Described electrode wire oscillations include a single cycle S.H. or triangular wave motion, Fig. 2(d), or a double cycle S.H. motion, Fig. 3 (not shown), only in the periods t H ; a single cycle S.H. motion only in the periods t H with the oscillation rest position at one wall of the weld preparation, Fig. 4 (not shown); and, in fillet welding, half cycle motions alternating oppositely in the periods t H with torch travel speed increased only every other period t H (Fig. 6, not shown). The number of electrode wires may be varied to prevent fluctuation in quantity of weld metal deposited; e.g. in butt jointing of pipes, in vertical-up welding three wires may be used with a fast torch travel speed and in vertical-down welding a single wire may be used with a slow torch travel speed. The Specification includes examples of butt and fillet welding including the use of A and CO 2 mixture shielding gas, steel backings, and consumable wire electrodes including 0À68- 0-8% Si, 1À55-1À63% Mn.