【摘要】 MnS夹杂物的控制是开发高品质齿轮钢的关键，采用Gleeble-3500热模拟试验机对20MnCr5齿轮钢热轧棒材进行单道次热压缩试验，研究了MnS夹杂物在应变速率1.0 s^-1，变形量15%～50%，变形温度900～1 100℃条件下热变形过程中的演变行为，同时研究了不同变形量和变形温度对MnS及其复合夹杂物的尺寸、长宽比、相对塑性的影响。结果表明，MnS夹杂物的碎化程度随变形量和变形温度发生周期性变化，在30%变形量时，随着温度升高，MnS夹杂物的相对塑性先减小后增加，由2.31减小到2.01，再增加到3.55；在950℃时，随着变形量的增加，MnS夹杂物的相对塑性一直减小，由2.98减小到2.01，再减小到0.94。结合MnS夹杂物的长宽比、尺寸、相对塑性的变化，在30%变形量时，20MnCr5齿轮钢的最佳变形温度为900℃，在950℃时，20MnCr5齿轮钢的最佳变形量为50%。更多还原

【Abstract】 The control of MnS inclusions is the key to the development of high-quality gear steel. In this paper, a Gleeble-3500 thermomechanical simulator was used to carry out single-pass hot compression experiments to investigate the hot deformation behavior of MnS inclusions in 20MnCr5 gear steel hotrolled bars with a strain rate of 1.0 s^-1, deformation strains of 15%～50%, and deformation temperatures of 900～1100 ℃. At the same time, the effects of deformation ratio and deformation temperature on the size, aspect ratio morphology and relative plasticity of MnS and its composite inclusions were systematically studied. The results showed that the fragmentation degree of MnS inclusion changes periodically with deformation ratio and temperature. At 30% deformation ratio, with rising temperature, the relative plasticity of MnS inclusion first decreases from 2.31 to 2.01 and then increases to 3.55. At 950 ℃, with the increase in deformation, the relative plasticity continuously decreases from 2.98 to 2.01, and then to0.94. Combined with the change in aspect ratio, size, and relative plasticity of MnS inclusions, the optimal deformation temperature of 20MnCr5 gear steel is 900 ℃ at 30% strain, and the optimal deformation ratio is 50% at 950 ℃.更多还原