C422钢气体渗氮及其缺口敏感性  

Gas nitriding and notch sensitivity of C422 steel

作　　者：张健 缪春辉 秦小龙 王若民 陈国宏 汤文明[3] ZHANG Jian;MIAO Chun-hui;QIN Xiao-long;WANG Ruo-min;CHEN Guo-hong;TANG Wen-ming(Anhui Xinli Electric Technology Consulting Co Ltd,Hefei 230601,China;Electric Power Research Institute,State Grid Anhui Electric Power Co Ltd,Hefei 230601,China;School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]安徽新力电业科技咨询有限责任公司,安徽合肥230601 [2]国网安徽省电力有限公司电力科学研究院,安徽合肥230601 [3]合肥工业大学材料科学与工程学院,安徽合肥230009

出　　处：《材料热处理学报》2022年第7期129-139,共11页Transactions of Materials and Heat Treatment

基　　金：安徽新力电业科技咨询有限责任公司科研项目(2016咨-CL-02)。

摘　　要：在氨气气氛下对C422(22Cr12NiMoWV)钢进行两段式气体渗氮,并研究了渗氮层的显微组织结构以及渗氮后C422钢的室温及高温力学性能,评价渗氮对该钢缺口敏感性的影响。结果表明:C422钢的渗氮层具有三层结构:表层为主要由Fe_(3)N、Fe_(4)N和CrN构成的化合物层,中间层为致密的α-Fe(N)扩散层,内层为α-Fe(N)相扩散进入钢基体而形成的过渡层。与未渗氮试样相比,随着渗氮时间延长,有无缺口C422钢渗氮试样的室温、高温拉伸强度和伸长率单调下降,屈服强度先增大后减小。渗氮层的断裂模式为解理断裂的脆性断裂。气体渗氮导致C422钢的室温缺口敏感性增大,但对其高温缺口敏感性影响不大。Two-stage gas nitriding of C422(22 Cr12 NiMoWV)steel was carried out in ammonia atmosphere.Microstructure of the nitrided layer and mechanical properties at room temperature and high temperature of the steel after nitriding were studied,and the effect of nitriding on notch sensitivity of the steel was evaluated.The results show that the nitrided layer of the C422 steel has a three-layer structure:the surface layer is a compound layer mainly composed of Fe_(3)N,Fe_(4)N and CrN,the middle layer is denseα-Fe(N)diffusion layer,and the inner layer is theα-Fe(N)phase diffuses into the steel matrix to form a transition layer.Compared with the non nitrided samples,with the increase of nitriding time,the room temperature and high temperature tensile strength and elongation of the nitrided samples of the C422 steel with or without notch decrease monotonically,and the yield strength increases first and then decreases.The fracture mode of the nitrided layer is brittle fracture of cleavage fracture.Gas nitriding increases the room temperature notch sensitivity of the C422 steel,but has little effect on its high temperature notch sensitivity.

关 键 词：C422钢 两段式气体渗氮 渗氮层 解理断裂 缺口敏感性 

分 类 号：TG156.8[金属学及工艺—热处理]