Effect of Solidification on Subsequent Ferrite-to-Austenite Massive Transformation in an Austenitic Stainless Steel Weld Metal

In an austenitic stainless steel weld metal solidified as primary ferritic single phase, subsequent ferrite-to-austenite transformation becomes massive when the postsolidification cooling is sufficiently rapid. The effect of solidification on the massive transformation was studied by analyzing microstructural changes during solidification and subsequent cooling. As a result of the analysis, crystallographic orientation relationship between the parent phase and the massive product phase, and the onset temperature of the massive transformation were clarified. A specific orientation relationship between the parent phase and the product phase by massive transformation was present. The onset temperature of the massive transformation was found to be below the T0 and inside the two-phase region of ferrite and austenite.