The reversion of martensite to austenite in certain stainless steels

An investigation has been made of the reversion of martensite () to austenite () in two stainless steels (i) Fe-16 wt% Cr-12 wt% Ni (of low interstitial content) (ii) Fe-15 wt% Cr-8 1/2 wt% Ni-2 wt% Mo-0.09 wt% C. The alloys were refrigerated to produce 12 to 15% martensite () and then heated for short times at various temperatures ranging from below A _s to above A _f. With rapid heating the reversion of to occurs largely by a shear mechanism. In the Fe-16Cr-12Ni alloy individual grains of transform to grains of reversed of similar size and shape. In the carbon-containing alloy there is evidence of break-up of the grains on reversion. An increase in the strength results from reversion and this is attributable mainly to the high dislocation density of the reversed .