Sulphide and Its Effect on Solidification Cracking in Weld Metal of Steel (Report 8)

Weld Solidification Crack Susceptibility of High Tensile Steel Containing Nickel

Abstract

Effects of sulphur, nickel, carbon, manganese and phosphorus on weld solidification crack susceptibility of various commercial and tentative high tensile steels (tensile strength: 50-100 kg/mm² class) have been investigated using the Longi-Varestraint test.
Main conclusions obtained are as follows:
1) Sulphur, even at 0.005% level, remarkably increases the solidification crack susceptibility.
2) Nickel and carbon promote the detrimental effect of sulphur (and phosphorus).
3) Even in the steel containing nickel and/or crabon, the high crack susceptibility induced by sulphur can be lowered by increasing the manganese content. And the manganese content required agrees with the value deduced theoretically in the previous paper. This is given by the condition that Mn⁵S is larger than 310-560.
4) Phosphorus also remarkably increases the crack susceptibility in the steel containing nickel (and carbon).