鋼およびその溶接部の溶融亜鉛中での破壊に及ぼす諸因子の検討

抄録

The effect of hardness and grain size of steels and their welds on fracture stress and sensitivity of Liquid Metal Embrittlement Cracking in molten Zinc (LMEC) was investigated. The experiment was conducted using commercial weldable structural steels and Sustained Load Test (SLT) was conducted in molten Zinc with heating range of 430°C-470°C.
The results obtained are as follows.
(1) The LMEC behavior of steels and welds in molten Zinc is of thermal activated process, and fractures are intergranular (IG) type which corresponds to actual LMEC in hot dip galvanizing.
(2) Estimation of fracture stress of steels and welds in molten Zinc is obtained by measuring Vicker's hardness and grain size, and these estimation values are correspond with test results.
(3) The sensitivity of LMEC is affected by hardness of steels and welds.