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基于金属-热-力耦合理论框架,利用DEFORM有限元分析软件建立了SDC99铣刀深冷处理多物理场耦合数值分析模型,探讨了深冷处理过程中铣刀内残留奥氏体的演变及分布规律,并借助X-ray衍射仪验证模拟结果。研究表明:淬火初始,铣刀中奥氏体的体积分数急剧下降,随着淬火时间的增加,奥氏体向马氏体的转变趋于平缓。淬火后,铣刀中残留奥氏体主要分布于刀刃根部附近和铣刀中空内圆柱面上,尤其是刀刃根部其残留奥氏体含量高达20%。进入深冷处理后,铣刀中的残留奥氏体继续向马氏体转变,与淬火初始相比,其奥氏体转变速率要小得多。深冷处理后,铣刀中残留奥氏体含量明显降低,其含量在3%以下,但仍主要聚集在刀刃根部。模拟结果与XRD定量分析结果比较吻合,验证了数值模拟的准确性和可靠性。
Based on the theoretical framework of metal-thermo-mechanical coupling, a finite element analysis software named DEFORM was used to establish the numerical simulation model for cryogenic treatment of multi-physics coupled with SDC99 milling cutter. The evolution and distribution of retained austenite in milling cutter during cryogenic treatment were discussed. The simulation results were verified by X-ray diffraction. The results show that the volume fraction of austenite in milling cutter decreases sharply at the beginning of quenching, and the austenite to martensite transformation tends to be gentle with the increase of quenching time. After quenching, the residual austenite in the cutter is mainly distributed near the root of the cutting edge and on the hollow cylindrical surface of the cutter, especially the residual austenite content in the root of the cutter blade reaches as high as 20%. After cryogenic treatment, the retained austenite in the milling cutter continues its transformation to martensite with a much lower rate of austenite transformation compared to the initial quenching. After cryogenic treatment, the residual austenite content in the milling cutter significantly decreased, its content below 3%, but still mainly gathered in the blade root. The simulation results are in good agreement with the quantitative analysis results of XRD, which verifies the accuracy and reliability of the numerical simulation.