Microstructural transformations in stress relieved type 316 stainless steel weld metal

The heat treatment of Type 316L weld metal containing small amounts of ferrite results in the transformation of the ferrite to chi or ..cap alpha.. phases after aging for only 3 hr at 850/sup 0/C. The chi-phase transformation is associated with a transitional M/sub 23/C/sub 6/ carbide, whereas the sigma-phase transforms directly from the ferrite.