溶接低温割れにおよぼす非金属介在物の影響(第1報)
溶接低温割れ限界応力に対する検討
1985 年 3 巻 2 号 p. 379-385
詳細
1985 年 3 巻 2 号 p. 379-385
In this report the effect of nonmetallic inclusions on weld cold cracking has been investigated. Q-T type HSLA experimental steels having various inclusion contents were employed. These steels had the different sulphur contents ranging between 0.006% and 0.032%.
Nonmetallic inclusions were mainly sulphieds and oxides. So inclusion contents were relative to sulphur and oxygen contents. The relationship between cleanliness and the sulphur+oxygen contents were indicated as following equation, d=0.0011 (S+O)+0.054 d: Inclusion area fraction at L-Z plane (%)
S+O: Sulphur+oxygen content (ppm)
The result of butt joint type implant test showed that lower critical stress decreased with decreasing inclusion contents. It was found that reducing inclusions increased the risk of weld cold cracking.
MnS inclusions had no significant effect on hardenability of steels. So the inclusion contents must be evaluated as one of the factors affected cold cracking.
