HY80型HT70鋼における多層すみ肉溶接割れの発生傾向

概要

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Cruciform-shaped and tee-shaped weld cracking tests were performed to make clear the effects of different conditions on the cracking behavior of multipass fillet weld in eight of HY80 type HT70 steels developed in Japan. In the cruciform-shaped weld cracking test under severe welding conditions, a few test steels developed various welding cracks including a crack in the heat-affected zone originating from the weld root, which had seemingly been caused by hydrogen. These cracks could be prevented by application of a high preheat and interpass temperature and adoption of a fully re-dried coated electrode. In steel U38 having a particularly high carbon equivalent and great plate thickness among the test steels, even under this crack-preventive condition the heat-affected zone developed a crack originating from the weld root, which was considered a hot crack due to liquation of constituents on the grain boundary. In the tee-shaped weld cracking test on two test steels which was carried out under as severe welding condition as the cruciform-shaped weld cracking test, development of welding cracks with great similarity in microscopic nature was observed. It was revealed that these cracks would not occur in single-pass welding, except under severe restraint; it did occur in two or more pass welding; and the time of crack occurence differed depending on the welding conditions.
独立行政法人海上技術安全研究所の論文
1971-07-01