Effect of the Deformation Amount on the Microstructure and Tensile Properties of 304 Stainless Steel with 2 wt% Al Content by Cold Rolling

The microstructure evolution during cold rolling and mechanical properties after solution treatment of 304 stainless steel with 2 wt% Al are investigated and the tensile properties of the steels are also tested. The results show that the steel consists of ferrite and austenite phases and small amounts of granular precipitates of Al4C3 and AlN, and the content of ferrite decreases gradually with increase of the deformation. For deformations of 30%, 50%, and 70%, the average grain sizes of the samples are 10.23, 8.66, and 7.13 mu m, respectively. After solution treatment grain refinement is obvious for the orientation and a large number of annealing twin grain boundaries are observed in the austenite phase. The sample with 50% deformation contains the highest volume fraction of recrystallized grains. The {001} cube texture and {001} rotated cube texture are present in the ferrite and austenite phases. The yield strength of the steel increases gradually with the increase in the cold rolling reduction; meanwhile the elongations are all above 40%. Especially for the sample with the reduction of 70%, the yield strength of the solution-treated specimen is 417 MPa, and the elongation is approximate to 50%.