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根据AISI1215钢热模拟压缩实验的结果,采用Poliak和Jonas提出的计算动态再结晶临界应变(εc)和临界应力(σc)方法,研究了形变温度和应变速率对εc和σc的影响规律。结果表明,在应变速度较低时(小于30 s-1),采用指数函数形式可以较好描述热加工参数Z(Zener-Hollomon参数)与εc,σc,εP(峰值应变)和σP(峰值应力)间的关系,实验分析的结果表明,峰值应变(临界应变)与Z参数之间表现为正比关系,Z参数增大(形变温度降低或应变速度增加),材料发生动态再结晶的临界应变增加,应力应变曲线上表现出的表观峰值应变增加。根据模型计算的结果,在实验数据的范围内,动态再结晶临界应变与应力应变曲线的峰值应变之间的比值约为0.4~0.5之间,明显小于一般工程应用中估计的0.7。根据模型的计算的结果,用中断淬火试验进行了验证,结果表明与模型计算值吻合良好。
According to the results of AISI 1215 steel thermal simulation compression experiment, the influence laws of deformation temperature and strain rate on εc and σc are studied by using the methods of calculating critical recrystallization (εc) and critical stress (σc) proposed by Poliak and Jonas. The results show that the exponential function can be used to describe the relationship between thermal processing parameters Z (ε), σc, εP (peak strain) and σP (peak stress) at low strain rate (less than 30 s-1) ). The experimental results show that there is a positive correlation between peak strain (critical strain) and Z parameter, increase of Z parameter (decrease of deformation temperature or increase of strain rate) and increase of critical strain of dynamic recrystallization , The apparent peak strain appearing on the stress-strain curve increases. According to the results of the model calculation, the ratio between the dynamic recrystallization critical strain and the peak strain of the stress-strain curve is about 0.4-0.5 in the range of the experimental data, which is obviously smaller than the estimated 0.7 in the general engineering application. According to the results of the model calculation, the results of the quenching test are validated and the results show good agreement with the calculated values.