表面硬化肉盛溶接の溶接割れに関する研究

概要

論文の詳細を見る
When one bead is welded on mild steel with a martensitic hardfacing coated electrode, no macrocrack occurs. But when overlapped beads are welded with it, transverse cracks occur in the tempered zone of the first bead. The principal cause of the cracking is hydrogen embrittlement under the stress resulting from contraction of tempered zone and expansion due to martensite transformation. This cracking is cold cracking which occurs at temperatures less than 100℃, and is delayed cracking, which occurs mainly along the grain boundary in which chromium carbides precipitate. Residual hydrogen in the first and second bead cause the transverse cracking. Both preheating and postheating resulted in crack-free welds. This is rather due to discharge of hydrogen resulting from relaxed cooling rate than to stress relaxation or softening of temperaed zone.
社団法人溶接学会の論文
1968-10-25