The work hardening behavior of this steel is displayed in Fig. 3. From this figure, it was observed that the hardness increased more rapidly up to a low strain (ε¼0.223) and the hardness increase rate became progressively lower until the maximum deformation was reached. Baldo and Mészáros [30] reported a similar result in lean duplex stainless steel, which also experiences strain-induced martensite transformation. According to these authors, work hardening of austenite occurs even at low strains. With increasing rolling reductions, SIM becomes the principal mechanism of strain accommodation, which leads to a progressive decrease in the slope of the work hardening curve (as seen in Fig. 3).