摘要
采用真空低压渗碳技术对304和316L奥氏体不锈钢进行表面强化,利用光学显微镜、扫描电镜、Thermo-Calc热力学软件、X射线衍射仪和显微硬度计等对渗碳层显微组织、相组成及硬度分布进行分析表征,计算了奥氏体不锈钢渗碳层中不同衍射峰的偏移量及渗碳前后晶格常数的变化量。结合钼对奥氏体不锈钢渗碳过程的影响,对比研究了304和316L奥氏体不锈钢渗碳后,在渗碳层深度、表面硬度及碳化物的析出规律等方面的差异。结果表明,经750℃真空渗碳2.6 h后,304和316L奥氏体不锈钢晶格常数分别增加了1.33%和1.14%,形成了由膨胀奥氏体和Cr_(23)C_(6)组成的渗碳层,Cr_(23)C_(6)在渗碳层中主要以条状沿膨胀奥氏体晶界析出,表面硬度较基体硬度均提升了两倍以上。
Surface strengthening of 304 and 316 L austenitic stainless steels was processed by using vacuum low pressure carburizing process. The microstructure, phase composition and microhardness distribution of the carburized layers were analyzed by means of optical microscope, scanning electron microscope, Thermo-Calc software, X-ray diffractometer and microhardness tester. The offsets of different diffraction peaks in the carburized layers and the changes in lattice parameters before and after carburizing of the tested steels were calculated. Combined with the effects of molybdenum on carburizing process of the austenitic stainless steels, the differences in the carburized layer thickness, surface hardness and mechanism of carbides precipitation after carburizing of 304 and 316 L austenitic stainless steels were compared and studied. The results show that the carburized layers produced by 750 ℃ carburizing for 2.6 h are composed of expanded austenite and CrCphases, the austenite lattice constant has increased by 1.33% and 1.14% respectively for 304 and 316 L stainless steels, and CrCis mainly precipitated in strip shape on the expanded austenite grain boundaries. The surface hardness of the 304 and 316 L stainless steels after carburizing at 750 ℃ for 2.6 h is over 2 times higher than that of substrate.
作者
程茹
田勇
宋超伟
王昊杰
Cheng Ru;Tian Yong;Song Chaowei;Wang Haojie(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang Liaoning 110819,China;School of Mechanical Engineering,Shenyang University of Technology,Shenyang Liaoning 110870,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2022年第9期1-6,共6页
Heat Treatment of Metals
基金
辽宁省自然科学基金(2020-MS-078)
辽宁省‘兴辽英才计划’项目(XLYC2007018)。
关键词
奥氏体不锈钢
真空低压渗碳
晶格膨胀
碳化物
austenitic stainless steel
vacuum low pressure carburizing
lattice expansion
carbides
作者简介
程茹(1998-),女,硕士研究生,主要研究方向为不锈钢表面强化,E-mail:C18839112661@163.com;通信作者:田勇,教授,博士,E-mail:tianyong@ral.neu.edu.cn。
