Influence of Si on strain-induced martensitic transformation in metastable austenitic stainless steel

The influence of silicon on the strain-induced martensitic transformation of metastable austenitic stainless steel (MASS) during cold rolling were studied. At 10% strain, martensitic nucleation was faster in samples with high silicon concentrations compared to samples with low silicon concentrations. At 20% strain, more martensite formed, and the martensite was more uniformly distributed throughout the sample with the high silicon content compared to the sample with the low silicon content. In addition, the strain hardening rate was higher in the high silicon content sample because the added silicon reduced the stacking fault energy (SFE) in MASS, promoted martensitic formation at low strains, and thereby increased the strain hardening rate in the MASS. As the strain was increased to 30%, a large amount of martensite formed in both samples, but the distribution of the martensite phase in the high silicon content sample was more uniform than in the low silicon content sample because the higher silicon content promoted martensitic nucleation at lower strains. This result is conducive to the rolling of ultra-thin strip stainless steel.