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为了探究0.30C-Cr-W渗氮轴承钢的最佳动态再结晶条件和热变形机理,利用Gleeble3800热模拟试验机对试验钢进行了等温热压缩模拟试验,试验变形温度为750~1050℃,应变速率0.01~10 s-1,变形量60%。结果表明,峰值应力随变形温度的降低和应变速率的升高而增大,在应变速率为0.01~0.1 s-1,变形温度为950~1050℃时,发生明显动态再结晶;具有双曲正弦函数型的本构方程能较好地描述0.30C-Cr-W渗氮轴承钢的流变行为;0.30C-Cr-W渗氮轴承钢的形变激活能为442.022 kJ/mol。基于动态材料模型和流变应力数据建立了热加工图。通过热加工图及微观组织的观察确定了变形温度950~1050℃,应变速率0.01~0.15 s-1为最佳热变形条件;变形温度750~950℃,应变速率1.2~10 s-1为流变失稳区。
In order to investigate the optimum dynamic recrystallization conditions and thermal deformation mechanism of 0.30C-Cr-W nitrided bearing steel, the isothermal hot compression simulation test of the test steel was carried out by using the Gleeble3800 thermal simulation testing machine, the deformation temperature was 750 ~ 1050 ℃ , Strain rate 0.01 ~ 10 s-1, deformation 60%. The results show that the peak stress increases with the decrease of the deformation temperature and the increase of the strain rate. At the strain rate of 0.01-0.1 s-1 and the deformation temperature of 950-1050 ℃, significant dynamic recrystallization occurs. The constitutive equation of function can well describe the rheological behavior of 0.30C-Cr-W nitrided bearing steel. The deformation activation energy of 0.30C-Cr-W nitrided bearing steel is 442.022 kJ / mol. A hot working diagram was established based on the dynamic material model and the flow stress data. The deformation temperature of 950 ~ 1050 ℃ and the strain rate of 0.01 ~ 0.15 s-1 were the best thermal deformation conditions through the thermal processing diagram and microstructure observation. The deformation temperature was 750-950 ℃ and the strain rate was 1.2-10 s-1 Variable loss of stability zone.