曲轴用非调质钢C38N2的静态再结晶行为

通过热模拟实验、光学金相及透射电镜分析观察，研究了奥氏体化条件、变形温度、变形速率、变形量以及道次间隔时间对曲轴用非调质钢C38N2轧制道次间的静态再结晶体积分数和残余应变率的影响规律.实验结果表明:随着变形温度的升高、变形速率的增大、变形量的增大或道次间间隔时间的增长，静态再结晶的体积分数逐渐升高，道次的残余应变率逐渐降低；原始奥氏体晶粒尺寸增大，静态再结晶体积分数降低，但变化不大；在1250℃以下，随着奥氏体化温度的升高，静态再结晶体积分数降低不明显，但在1250℃以上，奥氏体化温度的升高明显降低了静态再结晶体积分数.通过线性拟合以及最小二乘法，得到静态再结晶体积分数与不同变形工艺参数之间关系的数学模型；对已有残余应变率数学模型进行修正，得到含有应变速率项的残余应变率数学模型，拟合度较好. 

Static recrystallization behaviors of non-quenched steel C38N2 for crankshafts

The effects of austenitizing procedures,deformation temperature,deformation rate,deformation amount and inter-pass time between deformations on the volume fraction of static recrystallization and the residual strain ratio of non-quenched steel C38N2 for crankshafts were carefully investigated by hot simulation tests,quantitative metallography and transmission electron microscopy. Experimental observations show that,the volume fraction of static recrystallization increases and the residual strain ratio decreases when the deformation temperature,deformation rate,deformation amount and inter-pass time between deformations rise. The situation is opposite when the austenite grain size increases,but they change inconspicuously. In addition,the volume fraction of static recrystallization decreases gently when the austenitizing temperature rises below 1250℃. However,it sharply decreases when the austenitizing temperature rises above 1250℃. A mathematical model of the relationship between the volume fraction of static recrystallization and deformation parameters was derived by linear fitting and least square method. Besides,a mathematical model of residual strain ratio concerning the deformation rate term was obtained by modifying the existent mathematical model,and it fits the experimental results better.