Evaluation of the sliding wear and corrosion performance of triode-plasma nitrided Fe-17Cr-20Mn-0.5N high-manganese and Fe-19Cr-35Ni-1.2Si high-nickel austenitic stainless steels

SURFACE & COATINGS TECHNOLOGY

卷:409

Article

Tao, Xiao^1,2  Li, Xiaoying²  Dong, Hanshan²  Matthews, Allan³  Leyland, Adrian¹ 

[1] Univ Sheffield, Dept Mat Sci & Engn, Sheffield S1 3JD, S Yorkshire, England

[2] Univ Birmingham, Sch Met & Mat, Birmingham B15 2TT, W Midlands, England

[3] Univ Manchester, Sch Mat, Manchester M13 9PL, Lancs, England

关键词: Expanded austenite;    Plasma nitriding;    Sliding wear;    Aqueous corrosion;    Stainless steels;   

DOI  :  10.1016/j.surfcoat.2021.126890

来源: Elsevier

【 摘 要 】

Low-temperature plasma nitriding has been widely studied and applied, in enhancing the wear performance of austenitic stainless steels (ASSs) without losing corrosion resistance. In this work the wear and corrosion behaviours of two specialty ASSs, i.e. Staballoy (R) AG17 (Fe-17Cr-20Mn-0.5N, in wt%) and RA330 (R) (Fe-19Cr-35Ni-1.2Si, in wt%), were evaluated - and compared to AISI 304 - before and after low-temperature triode plasma nitriding (TPN) at 400 degrees C and 450 degrees C. A nitrogen interstitially-supersaturated expanded austenite layer (gamma(N)) was developed for all three ASSs after TPN treatment at 400 degrees C, which led to a) an approximately 4-fold increase in surface hardness, b) a reduction in specific wear rate of at least 2 orders of magnitude in unlubricated dry-sliding, and c) an improved resistance to pitting in 3.5 wt% NaCl aqueous solution. Large numbers of 'linear defects' (identified in TEM studies as strips of HCP-epsilon(N)) were seen in the gamma(N)-AG17 layer, that could be correlated to comparatively higher surface hardness and better wear resistance. Several slip/shear bands were also seen in the gamma(N)-330 layer, where short-range Cr-segregation could occur, leading to localised corrosion. More importantly, after TPN treatment at 450 degrees C, alloys AISI 304 and AG17 presented a deterioration in corrosion performance, whereas good corrosion performance was maintained for alloy RA330. Redistribution of Si (in preference to Cr) was revealed in gamma(N)-330 after TPN treatment at 450 degrees C, whereby Si-alloying at a significantly higher level than in the other two alloys investigated appears (in addition to the high Ni content in alloy 330) to be beneficial in delaying CrN precipitation, and thus in maintaining the good corrosion performance of gamma(N) after nitriding at low-to-intermediate temperatures.

【 授权许可】

Free