After applying torsion to cylindrical 304 stainless steel samples, a gradient structure along the radial direction was obtained. It was found that the volume fraction of α′-martensite increased gradually from the center to the surface of samples. The possibility of deformation-induced martensitic transformation was analyzed theoretically, whose conclusions were consistent with the experimental results. It was found that torsional deformation could produce abundant deformation twin and deformation-induced martensite, which could affect the tensile property of steel distinctly. The existence of deformation and martensite during torsion could increase the strength but deteriorate the ductility dramatically during the tensile test, which should be attributed to the weakening of work hardening ability. As a result of severe deformation, both strain-induced and stress-induced martensite have been observed. Also, two types of martensitic transformation mechanisms during torsional deformation were discussed.

在对圆柱形304不锈钢样品施加扭转后，获得了沿径向的梯度结构。发现α'-马氏体的体积分数从样品的中心到表面逐渐增加。从理论上分析了变形引起的马氏体相变的可能性，其结论与实验结果相吻合。结果表明，扭转变形会产生大量的变形孪晶和形变诱发的马氏体，从而明显影响钢的拉伸性能。扭转过程中变形和马氏体的存在可能会增加强度，但在拉伸试验中会大大降低延展性，这应归因于加工硬化能力的减弱。由于严重变形，已经观察到应变诱发和应力诱发的马氏体。此外，还讨论了扭转变形过程中的两种马氏体转变机理。