25Cr3Mo2WNiVNb低碳热模钢热变形规律研究

Study on thermal deformation law of 25Cr3Mo2WNiVNb low carbon hot die steel

本文利用Gleeble热压力模拟试验机模拟25Cr3Mo2WNiVNb低碳热模钢热穿孔过程中的热变形行为,研究分析了其在变形温度1000℃-1250℃,应变速率0.01-1S-1范围内的高温变形行为,分析其高温变形规律,基于试验钢高温流变曲线,结合应变量建立了改进型本构方程,绘制了基于DMM理论的热加工图,分析微观组织。结果表明:高温和低应变速率都能降低流变应力并促进动态再结晶。材料常数可以用应变量的主次函数表示,确定试验钢最佳的热穿孔工艺为:变形温度1125-1175℃;应变速率为0.05-0.15s-1.

In this paper,the deformation of 25Cr3Mo2WNiVNb low carbon hot die steel during hot piercing process was simulated by Gleeble hot pressure simulator.The high temperature deformation behavior of 25Cr3Mo2WNiVNb low carbon hot die steel was studied and analyzed in the range of deformation temperature 1000℃〜1250℃ and strain rate 0.01-1s'1.Based on the high temperature rheological curve of the test steel and combined with the strain,the improved constitutive equation was established and the DMM theory was drawn The results show that both high temperature and low strain rate can reduce flow stress and promote dynamic recrystallization.The material constant can be expressed as a function of seven degree of strain.The optimum hot piercing process is determined as follows:deformation temperature 1125-1175,strain rate 0.05-0.15s-1.