脱碳层对38CrMoAl钢离子渗氮的影响

doi:10.13251/j.issn.0254-6051.2020.10.038

摘要/Abstract

摘要： 对表面残存不同厚度脱碳层的38CrMoAl钢塔形试样进行离子渗氮,借助显微硬度计、光学显微镜、扫描电镜等多种手段,对试样渗速、硬度及渗氮前后的微观组织进行研究。结果表明,在残余的脱碳层里存在较严重的魏氏组织;残余脱碳越严重魏氏组织越多;离子渗氮的渗速随着表面脱碳层厚度的增加先增加后降低;魏氏组织中大量的铁素体为氮原子扩散提供了快速渗入通道及形成大量氮化物的场所,在渗层表面形成大量的鱼骨状、网状、脉状氮化物,数量随着脱碳层的增加而增加,并且不断向渗层深处延伸。38CrMoAl钢表面残存脱碳层虽然有加快渗速的作用,但会增加渗层的不良组织,增加渗层剥落的风险。故38CrMoAl钢制工件做普通调质应适当加大加工余量。

关键词: 38CrMoAl钢, 离子渗氮, 脱碳层, 扩散动力学

Abstract: Tower-like specimen of 38CrMoAl steel with different thickness decarbonized layer was plasma nitrided. Infiltration rate, surface hardness and microstructure of the specimen before and after nitriding was studied by microhardness tester, OM and SEM. The results show that the widmannstatten structure is found in residual decarbonized layer and gradually increases with increase of the decarbonized layer. The speed of plasma nitriding increases first and then decreases with the increase of decarbonized layer thickness. The diffusion expressway of nitrogen-atoms and formation of nitride is provided by ferrite in widmannstatten structure. There are many fishbone, net and nervation nitrides on the surface of diffusion layer and it exhibits increase tendency with the increase of number and depth of decarbonized layer. Although the residual decarburized layer on the surface of the 38CrMoAl steel can accelerate the penetration rate, it will increase the bad structure of the carburized layer and increase the risk of exfoliation. Therefore, the machining allowance of the 38CrMoAl steel workpieces should be appropriately increased.

Key words: 38CrMoAl steel, plasma nitriding, decarbonized layer, diffusion dynamics

中图分类号:

TG156

王艳芳, 殷挺峰, 李双喜. 脱碳层对38CrMoAl钢离子渗氮的影响[J]. 金属热处理, 2020, 45(10): 194-198.

Wang Yanfang, Yin Tingfeng, Li Shuangxi. Effect of decarbonized layer on plasma nitriding of 38CrMoAl steel[J]. Heat Treatment of Metals, 2020, 45(10): 194-198.

参考文献

[1]Yao C, Lei S, Chen K Z, et al. Plasmanitriding without formation of compound layer for 38CrMoAl hydraulic plunger[J]. Vacuum, 2017, 143: 98-101.
[2]王忠诚. 热处理操作简明手册[M]. 北京: 化学工业出版社, 2008.
[3]陈尧, 纪庆新, 魏坤霞, 等. 不同渗氮温度下38CrMoAl钢低氮氢比无白亮层离子渗氮 [J]. 中国表面工程, 2018(2): 23-28.
Chen Yao, Ji Qingxin, Wei Kunxia, et al. Plasma nitriding without white layer for 38CrMoAl steel with lower ratio of N2to H2 under different temperature[J]. China Surface Engineering, 2018(2): 23-28.
[4]李双喜, 孙启锋, 王鑫, 等. 38CrMoAl钢表面离子渗氮层剥落原因分析[J]. 金属热处理, 2019, 44(2): 223-226.
[5]周上祺, 侯琼, 任勤, 等. 38CrMoAl钢离子渗氮微观结构的研究[J]. 金属热处理, 2002, 27(10): 10-12.
Zhou Shangqi, Hou Qiong, Ren Qin, et al. Microstructure of ion nitridinglayer in 38CrMoAl steel [J]. Heat Treatment of Metals, 2002, 27(10): 10-12.
[6] GB/T 11354—2005,钢铁零件渗氮层深度测定和金相组织检验[S].
[7]宋涛, 顾军. 热处理工 [M]. 北京: 化学工业出版社, 2004.
[8]夏立芳, 高彩桥. 钢的渗氮[M]. 北京: 机械工业出版社, 1989.
[9]韩立民. 离子热处理[M]. 天津: 天津大学出版社, 1997.
[10]张德元, 彭文屹, 傅青峰, 等. 离子氮碳共渗中碳的作用及机理初探[J]. 金属热处理, 1998, 23(10): 26-27.
Zhang Deyuan, Peng Wenyi, Fu Qingfeng, et al. Effects and mechanism of carbon on ion nitrocarburizing[J]. Heat Treatment of Metals, 1998, 23(10): 26-27.
[11]Yan M F, Bell T. Effect of proportion of γ′-Fe₄N in compound layer produced during plasma nitriding on diffusion coefficient of lanthanum[J]. Journal of Materials Science Letters, 2001, 20(16): 1507-1508.
[12]徐冰仲, 张颖智. 离子氮化氮的渗入机理[J]. 金属热处理, 1983, 8(10): 29-41.
Xu Bingzhong, Zhang Yingzhi. The mechanism of nitrogen diffusion in ion-nitriding process[J]. Heat Treatment of Metals, 1983, 8(10): 29-41.
[13]周孝重, 陈大凯. 等离子体热处理技术[M]. 北京: 机械工业出版社, 1990.
[14]严国春, 何承绪, 孟利, 等. 取向硅钢表面氧化层的结构及其对渗氮的影响[J]. 材料工程, 2015, 43(12): 89-94.
Yan Guochun, He Chengxu, Meng Li, et al. Structure of surface oxide layer and effect on nitriding of grain-oriented silicon steel[J]. Journal of Materials Engineering, 2015, 43(12): 89-94.
[15]周潘兵, 周浪. 氧化层对渗氮动力学的影响[J]. 材料热处理学报, 2005, 26(4): 102-105.
[16]Borges J N, Belmonte T, Jaoul C, et al. Study of the transition from oxidation to nitriding in a single N₂ -H₂ -O₂ post-discharge[J]. Surface and Coatings Technology, 2005, 193(1-3): 132-136.
[17]潘健生, 胡明娟. 钢铁化学热处理原理[M]. 上海: 上海交通大学出版社, 1988.
[18]刘迨, 荀毓闽. 关于氮化层中脉状组织的探讨[J]. 金属热处理, 1979, 4(1): 15-23.
[19]Ratajiski J, Tacikowski J, Somers M A J. Development of compound layer of iron nitrides during nitfiding of steel[J]. Surface Engineering, 2003, 19(4): 285.