Microstructural changes produced by plastic deformation in the UNS S31803 duplex stainless steel

Plastic deformation by cold rolling produces important changes on microstructure of the duplex stainless steel UNS S31803. Structure refinement and martensitic transformation were detected and analyzed by microscopy, X-ray diffraction and magnetic measurements. True deformations in the range of 0.92–3.38 were applied. The maximum amount of α′ martensite was 30.2% obtained with the maximum deformation applied (3.38). The annealing at 400 °C promotes a further increase of α′ martensite content, as observed before in austenitic metastable steels. Hardness against deformation curves of AISI 304L and duplex steel were compared and analyzed. The stability of the martensite phase with temperature was investigated by magnetic measurements, and it is found that the reverse reaction α′ → γ starts between 500 and 520 °C.