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基于金属-热-力耦合理论,建立了C型环试样淬火和深冷处理的多物理场耦合数值模型,探讨了淬火和深冷处理过程中试样冷却行为和组织转变对其应力演变和分布的影响。研究表明:淬火和深冷处理过程中,由于C型环试样不同部位的冷却行为差异,导致温度变化和组织转变呈现非同时性。淬火和深冷处理后,试样残留奥氏体的含量分别为15.5%和2%左右,与实验测试结果吻合。在淬火过程中,试样等效应力变化曲线先后出现两个峰值,其中第一个应力峰值是由于试样心表温差引起的热应力所致,第二个应力峰值与试样心表组织转变的非同时性引起的组织应力密切相关;在深冷处理过程,试样心表温差和心表奥氏体体积分数差峰值出现的时间基本保持一致,且比淬火过程小两个数量级,导致试样的等效应力变化相比淬火过程要平缓得多。相比于淬火过程,深冷处理后试样残余应力的分布状态未发生明显改变,但试样的整体应力值有所下降,尤其是在缺口和最大壁厚附近残余应力得到释放。
Based on the theory of metal-thermo-mechanical coupling, a multi-physics coupled numerical model of quenching and cryogenic treatment of C-ring specimens was established. The stress evolution and distribution of the specimen cooling and microstructure changes during quenching and cryogenic treatment influences. The results show that during quenching and cryogenic treatment, due to the difference of cooling behavior in different parts of the C-ring specimen, the temperature change and microstructure change appear non-simultaneity. After quenching and cryogenic treatment, the content of retained austenite in the sample is about 15.5% and about 2% respectively, which is in good agreement with the experimental test results. During the quenching process, two peaks occur one after the other in the curve of equivalent stress. The first peak of stress is caused by the thermal stress caused by the temperature difference between the specimen heart and the second stress peak. Of the non-simultaneity caused by tissue stress is closely related to; in the cryogenic treatment, the sample heart temperature difference and the surface of the heart rate of austenite volume fraction difference appears basically the same time, and two orders of magnitude smaller than the quenching process, resulting in the sample The equivalent stress change is much softer than the quenching process. Compared with the quenching process, the distribution of residual stress after cryogenic treatment did not change significantly, but the overall stress of the sample decreased, especially in the gap and the maximum wall thickness near the residual stress is released.