挤压态42CrMo钢热塑性加工图及稳态变形参数识别

Processing maps and prediction of steady-state hot deformation parameters for an as-extruded 42CrMo steel

通过挤压态42CrMo钢多组试样的热压缩实验获得应变速率为0.01～10 s-1、变形温度为1123～1148 K条件下的真应力-应变数据,以此作为计算应变速率敏感指数(m值)﹑能量耗散因子(η值)和失稳判据(ζ值)三重判据的底层材料数据。利用三重判据构建的加工图对挤压态42CrMo高强度钢的热成形过程进行分析,得到了挤压态42CrMo强度钢在成型过程中的稳定区域和流变失稳区。结果表明:42CrMo钢的最优变形热力参数处于具有较高η值和较高ξ值的区域内。

Hot compression tests of as-extruded 42CrMo steel were conducted under deformation temperatures of 1123-1348 K and strain rates of 0.01-10 s^-1 on a Greeble 1500 thermal simulator. Then the true stress-strain data collected were employed in the calculations of strain rate sensitivity （ m-value）, power dissipation efficiency （η-value） and instability parameter （ζ-value） and the processing maps were constructed. The hot forming processes of as-extruded 42CrMo high-strength steel were analyzed by the processing maps and the stable regions and flow instability regions were identified in the processing map. The results show that the optimal thermal deformation parameters of 42CrMo high-strength steel lie in the regions with higher η-value and higher sζ-value.