On the Cracking of Metal in the Constrained Welding of Mild Steel

Abstract

The under-bead-crack is often seen on the high carbon and the alloy steels. But on the mild steel, if the constraint is severe for welding, mother-metal-crack is caused not only immediately under bead but at heat affected and not affected zones. In this research, using semi-killed, Si-killed and Al-killed steels, the crack sensitivity test in which a specimen is extended in the direction of the thickness of plate by the shrinkage of weld metal and the constraint was performed. And the mother-metal-crack of the mild steel was examined from the points of view of the hardenability and the cleanliness of material and the condition of constraint.