1973 Volume 42 Issue 11 Pages 1073-1084
Shape and structure of oxysulphides formed in TIG-arc weld metals of Fe-S-O ternary alloys and their effects on solidification crack susceptibility have been investigated. At the same time the applicability of the law of coincidence for change in liquid compositions during non-equilibrium solidification has been examined. Main conclusions obtained are as follows:
1) The shape and structure of oxysulphides and the crack susceptibility of weld metal can be classified by O/S ratio which was expected by the law of coincidence.
2) Filmlike oxysulphide formed at columnar grain boundary in weld metal with low O/S ratio changes into globular shape with increase in O/S ratio.
3) The shape of oxysulphide formed at cell or cellular dendrite boundary is always globular independent of O/S ratio.
4) Solidification crack always occurs along the filmlike oxysulphide formed in weld metal with low O/S ratio. No crack is observed along the globular oxysulphide formed in weld metal with high O/S ratio.
