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为了探究低碳CrNiMo渗碳轴承钢热压缩再结晶行为,利用Gleeble 1500D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900~1 050℃,变形速率为0.1、1、10s-1,变形量为10%、30%、50%。通过不同变形条件下,真应力-真应变曲线及晶粒度变化,对材料热变形动态再结晶过程进行了分析,线性回归出材料的形变激活能和流变应力本构方程,绘制出材料热加工工艺图,并试验出热压静态再结晶临界时间。结果表明,高变形温度、低应变速率和大变形量有利于材料动态再结晶发生,试验钢在温度为1 050℃、变形量为50%、变形速率为1s-1的条件下得到细小的再结晶晶粒,平均晶粒尺寸为14.97μm;低碳CrNiMo渗碳轴承钢变形量大于30%后形变激活能降速缓慢,50%变形量激活能为436.016kJ/mol,热加工工艺图与试验结果符合;900℃、1s-1、50%变形量时,材料达到动态再结晶热力学条件,保温静态再结晶,临界再结晶时间为5min。
In order to investigate the hot compression recrystallization behavior of low carbon CrNiMo carburized bearing steel, the isothermal hot compression simulation test of the test steel was carried out by using Gleeble 1500D thermal simulation test machine. The deformation temperature was 900 ~ 1050 ℃, the deformation rate was 0.1, 1 , 10s-1, deformation of 10%, 30%, 50%. The dynamic recrystallization process of the material was analyzed by means of the true stress-true strain curve and the variation of the grain size under different deformation conditions. The deformation activation energy and the flow stress constitutive equation of the material were linearly regressed to draw the material heat Process drawings, and test the static pressure recrystallization critical time. The results show that the high deformation temperature, low strain rate and large deformation are conducive to the dynamic recrystallization of the material. The test steel is obtained at a temperature of 1 050 ℃, a deformation of 50% and a deformation rate of 1s-1 The average grain size is 14.97μm; the deformation activation energy of low carbon CrNiMo carburized bearing steel is slower than 30%, and the activation energy of 50% deformation is 436.016kJ / mol. The heat treatment process and test The results are in line with; 900 ℃, 1s-1, 50% deformation, the material reaches the dynamic recrystallization thermodynamic conditions, static recrystallization, critical recrystallization time of 5min.