高炭素鋼のガスシールドアーク溶接に関する研究 ＩＩ 割れ試験法による溶接部の高温割れ感受性に及ぼす母材Ｓの影響に関する検討

Abstract

Effects of sulphur contents in base metals (0.008-0.026%S) on hot cracking susceptibility of welds for CO2-O2 gas shielded arc welding of high carbon steel (0.65-0.70%C) have been investigated with angle expanding type cracking test (gas mixture ratio, 0, 20, 40%) and 15 ton class tensile restraint cracking test (CO2+20%O2). The results obtained are as follows:(1) In case of angle expanding type cracking test, remarkable variation of hot cracking susceptibility of weld metals are not recognized by different sulphur contents.(2) In case of 15 ton class tensile restraint cracking tests, hot cracking susceptibility of welds (mainly heat affected zone) are affected by sulphur contents in base metal and the relation between hot cracking susceptibility of welds and sulphur contents in base metals have been clarified with increasing tensile stress during testing.