Abstract Several studies have shown that cryogenic treatments improve many properties of tool steels. Basically the cryogenic treatment reduces the amount of retained austenite and promotes ultrathin carbides precipitation. In this study, samples of AISI D6 were submitted to several heat treatment cycles, aiming to analyze the influence of cryogenic treatment on microstructure, impact toughness and wear resistance. These cycles were quenching and tempering, quenching and tempering followed by deep cryogenic treatment (2 and 24 h) and, finally, quenching and tempering followed by deep cryogenic treatment plus double tempering. By the comparison with other studies and by the application of techniques such as Electron Microscopy, Image Analysis and X-ray Diffraction, it was observed that the hardening step (austenitization time and temperature) plays a fundamental role in the retained austenite level and in the cryogenic treatment results. The thermal cycles act both on the martensite formed directly from the quenching (primary martensite) and on the martensite formed from the retained austenite. It was concluded that cryogenic treatment followed by double tempering produced a reduction in the amount of retained austenite and consequently leads to secondary carbides precipitation. This fact has a marked role on the mechanical properties, keeping the wear values unchanged for the studied conditions.

中文翻译：

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深冷处理对AISI D6工具钢组织、冲击韧性和耐磨性的影响

摘要 多项研究表明，低温处理可以改善工具钢的许多性能。基本上，深冷处理减少了残余奥氏体的量并促进了超薄碳化物的析出。在本研究中，AISI D6 样品进行了多次热处理循环，旨在分析低温处理对微观结构、冲击韧性和耐磨性的影响。这些循环是淬火和回火，淬火和回火，然后是深冷处理（2 和 24 小时），最后是淬火和回火，然后是深冷处理加双重回火。通过与其他研究的比较以及电子显微镜、图像分析和 X 射线衍射等技术的应用，据观察，硬化步骤（奥氏体化时间和温度）对残余奥氏体水平和低温处理结果起着重要作用。热循环作用于直接由淬火形成的马氏体（初生马氏体）和由残余奥氏体形成的马氏体。得出的结论是，深冷处理后进行双重回火会减少残余奥氏体的数量，从而导致二次碳化物析出。这一事实对机械性能有显着影响，在研究条件下保持磨损值不变。热循环作用于直接由淬火形成的马氏体（初生马氏体）和由残余奥氏体形成的马氏体。得出的结论是，深冷处理后进行双重回火会减少残余奥氏体的数量，从而导致二次碳化物析出。这一事实对机械性能有显着影响，在研究条件下保持磨损值不变。热循环作用于直接由淬火形成的马氏体（初生马氏体）和由残余奥氏体形成的马氏体。得出的结论是，深冷处理后进行双重回火会减少残余奥氏体的数量，从而导致二次碳化物析出。这一事实对机械性能有显着影响，在研究条件下保持磨损值不变。