鋼材の熔接諸條件と冷却時間(第6報)

Abstract

The cooling curve from 800°C and the cooling time from 800°C to 500°C near the fusion line in case of C.S. arc welding process were measured for various welding conditions. Welding conditions such as type of welded joint, plate thickness, welding current, the proceeding rate of bead, arc voltage or open voltage, diameter of filler wire, volume per unit time of supplied gas, volume percentage of oxygen in supplied mixed gas CO2-O2, and bead length were changed and-effects on cooling time were observed. However the main factors which influence the cooling time are type of welded joint, plate thickness and arc energy per unit bead length J=60EI/v, as those in case of the other arc welding processes.In case of C.S. arc welding of carbon steels or high tensile steels (or low alloy steels), the relations between the welding conditions and cooling time from 800°C to 500°C near fusion line are presented by the following formula. S=(60El/v)1.7/1.11×105×β{1+2/πtan-1(t-13/3.5)} where E : arc voltage, VoltI : welding current, Amp.v : the proceeding rate of bead, cm/min.t : plate thickness, mmβ:content{1 for bead on a plate, 1.7 for T-fillet joint.This formula is applied when the bead length is above about 10cm. The nomograph of this formula is constructed in Fig. 19. The cooling time can be read easily from the welding conditions by this nomograph.