研究了２２Ｍｎ－１３Ｃｒ－５Ｎｉ－０．２５Ｎ钢的应变硬化行为。结果表明：变形初期，形变孪晶的形成降低应变硬化指数；随应变增加，先形成的形变孪晶阻碍位错运动和阻碍其它｛１１１｝形变孪晶形成，从而提高应变硬化指数。应变硬化指数ｎ与真应变量ε的关系为ｎ＝ａ·１ｎｅ＋ｂ。晶粒尺寸对ｎ值的影响与应变量有关，当ε＜０．１时，随晶粒尺寸增大，应变硬化指数先降后升；当ε≥０．１时，应变硬化指数随晶粒尺寸的增大而增加。 The strain hardening behavior of 22Mn-13Cr-5Ni-0.25N steel was studied. The results show that the formation of deformation twins reduces the strain hardening index at the early stage of deformation. With the increase of strain, the deformation twins that are formed first prevent the dislocation movement and prevent the formation of other {111} deformation twins, thus increasing the strain hardening exponent. The relationship between strain hardening index n and true strain ε is n = a · 1ne + b. The influence of grain size on n value is related to the amount of strain. When ε <0.1, the strain hardening index first decreases and then increases with the increase of grain size. When ε≥0.1, the strain hardening index increases with the grain size Increase the size increases.