IMPROVEMENT OF MECHANICAL PROPERTIES OF MARTENSITIC STAINLESS STEEL BY PLASMA NITRIDING AT LOW TEMPERATURE

作     者：Y. T. Xi D.X. Liu D. Han Z.F. Han 

作者机构：Corrosion and Protection Research Lab Northwestern Polytechnical University Xi＇an 710072 China Xi＇an Shaangu Power Co. Ltd Xi＇an 710611 China 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2008年第21卷第1期

页      面：21-29页

核心收录：

学科分类：0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0703[理学-化学] 0811[工学-控制科学与工程] 

基　　金：supported by National Natural Science Foundation of China(Nos.50171054 and 50671085) National High Technical Research and Development Programme of China(No.2007AA03Z521) 

主　　题：Martensitic stainless steel Plasma nitriding Low temperature Mechanical properties 

摘      要：A series of experiments were carried out to study the influence of low temperature plasma nitriding on the mechanical properties of AISI 420 martensitic stainless steel. Plasma nitriding experiments were carried out for 15 h at 350℃ by means of DC- pulsed plasma in 25%N2＋ 75%H2 atmosphere. The microstructure, phase composition, and residual stresses profiles of the nitrided layers were determined by optical microscopy and X-ray diffraction. The microhardness profiles of the nitridied surfaces were also studied. The fatigue life, sliding wear, and erosion wear loss of the untreated specimens and plasma nitriding specimens were determined on the basis of a rotating bending fatigue tester, a ball-on-disc wear tester, and a solid particle erosion tester. The results show that the 350℃ nitrided surface is dominated by c-Fe3N and ON, which is supersaturated nitrogen solid solution. They have high hardness and chemical stabilities. So the low temperature plasma nitriding not only increases the surface hardness values but also improves the wear and erosion resistance. In addition, the fatigue limit of AISI 420 steel can also be improved by plasma nitriding at 350℃ because plasma nitriding produces residual compressive stress inside the modified layer.