42CrMo钢在不同温度下单向拉伸的流变特征

Flow characteristics of 42CrMo steel on unidirectional tension at different temperatures

对42CrMo调质钢在-150～700℃区间进行拉伸试验,发现在一定应变条件下出现应力突然增大的"应力台阶"现象,"应力台阶"的高度与试验温度存在一定关系。随着温度提高,流变应力及强度均降低,但是在0～250℃区间出现应力平台。流变应力随温度的变化与位错同固溶原子之间的交互作用有关。在低温条件下,钢的断裂方式以解理为主,随着温度提高逐渐过渡到韧窝断裂。

Tensile test of quenched and tempered 42CrMo steel was carried out at different temperatures ranging from - 150 ℃ to 700℃. The results show that the flow stress has an abrupt increase under certain condition, and stress increment depends upon the experimental temperatures. Both of the flow stress and strength decrease with increasing of temperature, whereas a stress platform occurs in the temperature range from 0℃ to 250 ℃. The relationship of stress with temperature is resulted from the interaction between dislocations and solute atoms. Meanwhile, fracture mode of the steel displays mainly cleavage, changing into dimples with increase of temperature.