在Gleeb-3500型热模拟试验机上对铸态GCr15SiMn轴承钢进行热压缩试验，研究了变形温度（1 223~1 423 K）和应变速率（0.1~10.0 s^-1）对流变应力的影响，观察了显微组织；采用基于TEGART和SELLARS等提出的Arrhenius方程，通过试验数据的拟合建立了试验钢的流变应力本构方程，并进行了验证。结果表明：在试验条件下变形时，试验钢的流变曲线均呈现出动态再结晶软化特征，提高变形温度或降低应变速率均可降低其流变应力；在应变速率1.0 s^-1条件下，升高变形温度会促进试验钢的动态再结晶，同时也使晶粒长大粗化；在变形温度1 423 K、应变速率0.1~1.0 s^-1条件下，应变速率越大，动态再结晶晶粒越细；由建立的流变应力本构方程预测得到的峰值应力与试验结果的平均相对误差为0.393%，说明本构方程较准确。

Hot-compression test of as-cast GCr15SiMn bearing steel was carried out on a Gleeb-3500 thermal simulator. The effects of deformation temperature (1 223-1 423 K) and strain rate (0.1-10.0 s^-1) on flow stress were studied, and the microstructure was observed. The flow stress constitutive equation of the test steel was established by fitting the experimental data on the basis of the Arrhenius equation given by TEGART and SELLARS, and was verified. The results show that when deforming under test conditions, all the flow curves of the test steel showed a dynamic recrystallization characteristic; increasing the deformation temperature or reducing the strain rate could reduce the flow stress. At the strain rate of 1.0 s^-1, increasing the deformation temperature helped the dynamic recrystallization of the test steel and coarsened the grains. At the deformation temperature of 1 423 K and the strain rates of 0.1-1.0 s^-1, the greater the strain rate, the finer the dynamic recrystallized grains. The peak stresses were predicted by the established flow stress constitutive equation. The average relative error between the calculation value and the test value was 0.393%, indicating that the constitutive equation was relatively accurate.