GRAIN REFINING OF ( alpha plus alpha prime ) TWO PHASE STAINLESS STEEL.

The microduplex process of a Fe-16%Cr-5%Mo-8%Co-2%Ni alloy has been investigated. The alloy has a fully ferritic structure after quenching from 1573 K, then austenite (followed by martensitic transformation during air cooling) decomposes from the ferrite during reheating up to the temperature range of the ( alpha plus gamma ) phase. If the ferrite was cold rolled about 90% prior to reheating, strain-induced precipitation of Laves phase occurs in the temperature range 850-950 K. On 923 K aging, the precipitates play role in suppression of subgrain growth. In the temperature range 1000-1300 K, austenite nucleates along slip bands and deformation twins, resulting in a microduplex structure. At temperatures above 1300 K where recrystallization of ferrite matrix can preferentially occur, the structure coarsened.