复合表面处理改善304不锈钢的微观结构和耐磨性  

Microstructure and Wear Resistance of 304 Austenitic Stainless Steel Improved by Duplex Surface Treatment

作　　者：沈倩倩 向莉 张瑜[1] 李雪莎 聂朝胤[1] SHEN Qian-qian;XIANG Li;ZHANG Yu;LI Xue-sha;NIE Chao-yin(Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学,重庆400715

出　　处：《表面技术》2021年第5期208-215,共8页Surface Technology

基　　金：中央高校基本科研业务费(自然科学)(XDJK2020D002)。

摘　　要：目的提高奥氏体不锈钢的耐磨性。方法采用电镀法在304奥氏体不锈钢表面进行镍涂层预处理,然后在450℃及以下,于流动的高纯度NH3中进行气体渗氮,获得复合表面处理试样。使用扫描电子显微镜、X射线衍射仪和显微硬度仪,研究了渗氮层的组织、相组成和显微硬度。使用球盘式摩擦磨损试验机,选用硬度相差很大的两种材料GCr15和Si_3N_4作为摩擦副,对其耐磨性进行了探讨。结果在400℃时,复合表面处理试样的基底表面生成约6.34μm厚的连续渗氮层,而单一渗氮试样表面没有渗氮层形成,而且450℃复合表面处理试样的渗氮层厚度为24.26μm,约是单一渗氮处理试样的7.85倍。400℃复合表面处理试样的渗氮层主要由γN-Fe组成。450℃复合表面处理试样的渗氮层主要由γN-Fe和少量铬的氮化物组成。400℃和450℃复合表面处理试样的最大硬度分别为780HV0.05和1450HV0.05,分别是原材料的3.3和6.2倍。与原材料相比,以GCr15作摩擦副时,400℃和450℃复合表面处理试样的磨损量分别下降了约75.7%和89.4%;以Si_3N_4作摩擦副时,400℃和450℃复合表面处理试样的磨损量分别下降了约82.5%和88%。结论镍涂层预处理有利于提高气体渗氮效率。复合表面处理明显提高了材料的渗氮层厚度、硬度及耐磨性。To improve the wear resistance of 304 austenitic stainless steel,in this paper,the surface of 304 austenitic stainless steel samples was pre-plating nickel treated by an electroplating method,subsequently gas nitriding was performed in flowing high-purity NH3 gas below 450℃.The microstructure and microhardness of the nitrided layer were carefully studied by scanning electron microscope(SEM),X-ray diffractometer(XRD)and microhardness tester.In order to extend the application of nitrided stainless steel,GCr15 and Si3N4 materials with serious different hardness were selected to simulate different service environments for counterparts.The wear resistance was evaluated by using a ball-disc tribometer.A continuous nitrided layer about 6.34μm thick was formed on the surface of the substrate in the duplex surface treated sample at 400℃,but no nitrided layer was formed on the surface of the single nitrided sample.The thickness of the nitrided layer of the duplex surface treated sample at 450℃was 24.26μm,which was 7.85 times that of the single nitrided sample.The nitrided layer of the duplex surface treated sample at 400℃was mainly composed ofγN-Fe,and that of the duplex surface treated sample at 450℃was mainly composed ofγN-Fe and a small number of chromium nitrides.The maximum hardness of 400℃and 450℃duplex surface treated samples was 780HV0.05 and 1450HV0.05,respectively,which is 3.3 and 6.2 times that of the original material.Compared with the original material,the wear volume loss of duplex surface treated samples at 400℃and 450℃had fallen by about 75.7%and 89.4%with GCr15 as counterparts,and that had fallen by about 82.5%and 88%with Si3N4 as counterparts.The results show that the pre-plating nickel treatment is great benefit to gas nitriding,and the thickness of the nitrided layer,microhardness and wear resistance of duplex surface treated samples were remarkably improved.

关 键 词：复合表面处理 304不锈钢 镍涂层 渗氮层 微观结构 显微硬度 耐磨性 

分 类 号：TG156.8[金属学及工艺—热处理]