Analysis of the solidification process in Fe–36%Ni weld metal with NbC crystallization

Abstract

When austenitic high-alloy steel weld metal sustains single-phase solidification generally described as A-mode solidification, this is well-known to result in heightened solidification cracking susceptibility.^1–3 To reduce the solidification cracking susceptibility of austenitic stainless steel, it is known to be effective to undertake component modification such as to obtain a solidification mode called the AF mode or FA mode involving the ä phase being crystallized or retained.^{1, 2} To obtain a complete γ solidification mode in the case of high Nibase alloys, such as Fe–36%Ni alloy, however, it is necessary to arrange for high Cr addition in order to achieve component modification facilitating AF or FA mode solidification such as affects austenitic stainless steel. The result of such addition, however, is that impairment of base metal properties also self-evidently cause heavy loss of hot workability in a way that makes this approach difficult to describe as effective.