TP304L不锈钢快速热处理的固溶渗氮  

Solid Solution Nitriding of TP304L Stainless Steel During Short-time Heat Treatment

作　　者：刘蔚 吴静娜 蔡志刚 苏诚 沈育明 陆军伟 钱炯 钟强 LIU Wei;WU Jing-na;CAI Zhi-gang;SU Cheng;SHEN Yu-ming;LU Jun-wei;QIAN Jiong;ZHONG Qiang(Zhejiang Province High-performance Tube Forming Engineering Technology Research Center for Nuclear Power,Jiuli R&D Center,Zhejiang Jiuli Hi-Tech Metals Co.,Ltd.,Huzhou 313028,China)

机构地区：[1]浙江久立特材科技股份有限公司久立研究院浙江省核电用高性能管材成形工程技术研究中心,浙江湖州313028

出　　处：《表面技术》2021年第12期167-173,201,共8页Surface Technology

基　　金：国家新材料生产应用示范平台建设项目(TC170A5ST-1)。

摘　　要：目的研究TP304L不锈钢在N;气氛下快速高温热处理的固溶渗氮行为。方法对样管进行快速高温热处理,分别采用N;、Ar作为保护气氛,制备固溶渗氮样管及无渗氮样管。使用SEM-EDS、XPS对两种样管进行组织观察和成分分析,采用显微硬度仪测量表面硬度,并通过晶间腐蚀实验和电化学点蚀实验对比耐蚀性。结果相比于无渗氮样管,渗氮样管表面的平均硬度上升30HV_(0.1)。能谱结果显示,渗氮样管表面N元素含量升高,N的渗透深度约为2μm,扫描电镜没有发现化合物相。通过XPS的元素价态分析,渗入的N元素会形成类似α″-Fe;N;/α′-Fe;N中Fe—N键的结构,以固溶和过饱和固溶的形式存在,没有形成Cr—N键,说明没有出现有害的Cr2N相。渗氮样管的抗晶间腐蚀能力不变,电化学测试结果表明,点蚀电位提高20~100 mV,抗点蚀能力提高。结论在N2气氛中进行快速高温热处理,TP304L不锈钢会发生高温固溶渗氮行为,过饱和N元素没有析出Cr-N相或Fe-N相,且使材料的表面硬度、耐蚀性提高。The work aims to study the solid solution nitriding behavior of TP304 L stainless steel during short-time hightemperature treatment in N2 atmosphere.Nitrided tubes and non-nitrided tubes were prepared by short-time high-temperature heat-treatment with N2 and Ar as protective atmospheres.SEM-EDS and XPS were used for microstructure observation and composition analysis.Vickers Indenter was used to measure the surface hardness,and the corrosion resistance was compared through intergranular corrosion test and electrochemical pitting corrosion test.Compared to non-nitrided tubes,the average surface hardness of the nitrided tube increased by 30 HV_(0.1).The content of N element on the surface of the nitrided tube was increased,and the penetration depth of N was about 2 μm.No nitride compounds were found by SEM.The analysis of element valence state by XPS indicated that the N atoms formed Fe-N bonds,which mostly corresponded to α″-Fe16 N2/α′-Fe8 N,as the form of solid solution and supersaturated solid solution.Cr-N bond was undetectable,indicating that there is no harmful Cr2 N phase.The electrochemical pitting potential of nitrided tubes increases by 20~100 mV,with improved pitting resistance,and its resistance property of intergranular corrosion was equal to non-nitrided tubes.In summary,the short-time high-temperature heat-treatment of TP304 L stainless steel in N2 atmosphere caused solution nitriding behavior,which improved the surface hardness and corrosion resistance,without the precipitation of Cr-N or Fe-N phase.

关 键 词：渗氮 TP304L不锈钢 快速高温热处理 过饱和固溶 点蚀电位 

分 类 号：TG156.8[金属学及工艺—热处理]