Crystallography of Widmanstätten austenite in duplex stainless steel weld metal

Abstract

Two kinds of austenite grow from δ-ferrite during the cooling of the duplex stainless steel weld deposits studied here, Widmanstätten plates and allotriomorphs which precipitate at δ– δ grain boundaries. It is found using microtexture measurements that the preferred crystallographic orientation of the Widmanstätten austenite can be estimated using established theory if it is assumed that there is an interaction between external stress and the growing plates. It is also demonstrated that the Widmanstätten and allotriomorphic forms of austenite may not be identically oriented even when the former appears to originate from the latter; this may be a consequence of differences in the transformation mechanisms of these two forms of austenite.