GB1500251A - Method of gas shielded arc welding - Google Patents

Abstract

1500251 Welding by fusion NIPPON KOKAN KK 14 Jan 1976 19961/76 Heading B3R A method of MIG welding of steel, e.g. straight or helical seam welding of pipes for use in low temperature pipe lines or welding of thick plates, shielding gas, comprising a mixture of inert gas (e.g. argon or helium) and, in quantities less than 30 and 5% respectively of the gas mixture, of carbon dioxide or oxygen, is supplied at 50 to 200 1./min., the electrode is solid, of low alloy steel and of 3À0 to 6À4 mm. diameter, welding current is 600 to 1500 amp., arc voltage is 23 to 36 volts, and weld speed is 300 to 1500 mm./min. The method may include the use of at least two electrodes in line ahead, the distance between adjacent electrodes being 10 to 100 cm., and the above gas supply, welding current and arc voltage range applying to each electrode. Such a plurality of electrodes may be of differing types and may operate with differing welding currents, arc voltages and carbon dioxide shielding gas contents. The Specification discloses examples of twosided welding, the use of a shielding gas pressure of 3 Kg./cm.<SP>2</SP>, and workpiece and electrode metals respectively of 3À5 Ni-Mn-Mo-Cr steel and Mn-Ni-Mo-Ti-B. The gas shielding may be effected by a double, nested flow, torch, and an additional trailing flow may be provided to shield the surface of the deposit.