石油压裂阀箱用17-4PH不锈钢热变形行为及热加工图

Hot deformation behavior and hot processing map of 17-4PH stainless steel for oil fracturing valve box

利用Gleeble-3500热模拟试验机研究了石油压裂阀箱用17-4PH不锈钢在变形温度为1050~1250℃,应变速率为0.01~0.5 s^(-1)区间的热变形行为。结果表明:试验钢热变形流变曲线呈现出典型的动态再结晶特征,最大变形抗力随着变形温度的升高和应变速率的降低而减小,表明动态再结晶更充分。通过回归计算获得了17-4PH不锈钢热变形过程中最大变形抗力的预测模型及峰值应变模型,并确定了其再结晶热激活能约为485.19 kJ·mol^(-1)。建立了不同真应变下的热加工图,并结合再结晶晶粒组织演化规律明确了获得细小均匀组织的热加工工艺参数范围,进而提出了17-4PH不锈钢的合理锻造工艺窗口。

The hot deformation behavior of 17-4 PH stainless steel for oil fracturing valve box at deformation temperature of 1050-1250℃and strain rate of 0.01-0.5 s^(-1) was studied by Gleeble-3500 thermal simulator test machine.The results show that the hot deformation flow curves of test steel show typical dynamic recrystallization characteristics.The maximum deformation resistance decreases with the increase of deformation temperature and the decrease of strain rate,which indicates that dynamic recrystallization is more sufficient.The prediction model of the maximum deformation resistance and the peak strain model of 17-4 PH stainless steel during hot deformation were obtained through regression calculation.The activation energy of recrystallization is determined to be about 485.19 kJ·mol^(-1).The hot processing maps at different strains were established.Combined with the microstructure evolution law of recrystallized grains,the ranges of hot processing parameters for obtaining fine and uniform microstructure were optimized and the reasonable forging process window of 17-4 PH stainless steel was put forward.