真空渗碳18CrNiMo7-6钢中碳化物的析出规律  

Carbide precipitation law in vacuum carburized 18CrNiMo7-6 steel

作　　者：张明皓 韩颢源 徐跃明 李俏 高直 周乐育 Zhang Minghao;Han Haoyuan;Xu Yueming;Li Qiao;Gao Zhi;Zhou Leyu(Beijing Research Institute of Mechanical&Electrical Technology Ltd.,Beijing 100083,China;School of Materials Science&Engineering,University of Science and Technology Beijing,Beijing 100083,China;China Machinery Huanyu Certification and Inspection Co.,Ltd.,Beijing 102609,China)

机构地区：[1]北京机电研究所有限公司,北京100083 [2]北京科技大学材料科学与工程学院,北京100083 [3]中机寰宇认证检验股份有限公司,北京102609

出　　处：《金属热处理》2022年第5期171-176,共6页Heat Treatment of Metals

基　　金：国家重点研发计划(2018YFB2001900)。

摘　　要：采用淬火膨胀仪进行模拟试验,通过对18CrNiMo7-6钢的显微组织、硬度分布的表征,研究了经真空渗碳后18CrNiMo7-6钢在冷却过程中碳化物的析出规律。结果表明,在980℃保温30 min后,试验钢中的碳化物完全溶解;快速冷却至600℃保温20 min后,渗层组织充分转变为细片层珠光体形貌组织;再升温至830℃保温20 min并以20℃/s的冷速气冷至室温后,室温组织出现不同形态的碳化物,马氏体组织较热处理前的原始组织得到了细化,且硬度及淬硬层深度较热处理前显著提升。Using quenching dilatometer for simulation, carbide precipitation law during cooling of the vacuum carburized 18 CrNiMo7-6 steel was studied by characterizing the microstructure and hardness distribution. The results show that after austenitizing at 980 ℃ for 30 min, the carbides are completely dissolved. After cooling quickly to 600 ℃ and holding for 20 min, the infiltration layer microstructure is fully transformed into fine lamellar microsturcture with pearlite morphology. Then after heating to 830 ℃ and holding for 20 min and cooling with protective atmosphere at 20 ℃/s to room temperature, carbides with different shapes appear, and the martensite is finer than that in the original microstructure before the heat treatment. Besides, the hardness is higher and the depth of hardened layer is deeper than those before the heat treatment.

关 键 词：真空渗碳 18CrNiMo7-6钢 碳化物 热处理 显微组织 淬硬层深度 

分 类 号：TG156.1[金属学及工艺—热处理]