Effect of low-temperature surface hardening by carburization on the fatigue behavior of AISI 316L austenitic stainless steel

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:769

Article

Peng, Yawei^1,2,3  Liu, Zhe^1,2  Chen, Chaoming^1,2  Gong, Jianming^1,2  Somers, Marcel A. J.³ 

[1] Nanjing Tech Univ, Sch Mech & Power Engn, 30 Puzhu South Rd, Nanjing 211816, Jiangsu, Peoples R China

[2] Jiangsu Key Lab Design & Manufacture Extreme Pres, 30 Puzhu South Rd, Nanjing 211816, Jiangsu, Peoples R China

[3] Tech Univ Denmark, Dept Mech Engn, Prod Storvet B 425, DK-2800 Lyngby, Denmark

关键词: Austenitic stainless steel;    Low-temperature carburization;    Fatigue behavior;    Residual stress relaxation;   

DOI  :  10.1016/j.msea.2019.138524

来源: Elsevier

【 摘 要 】

The influence of low-temperature gaseous carburization on the fatigue behavior of AISI 316 L austenitic stainless steel was investigated. Tension-compression axial fatigue tests were performed under ambient conditions on untreated and carburized AISI 316 L. The results show that the carburized AISI 316 L has a 22% higher endurance limit compared to untreated AISI 316 L. Fractography investigations with scanning electron microscope (SEM) reveal that for the untreated AISI 316 L fatigue cracks initiate at the surface regardless of the applied stress level. For the carburized AISI 316 L fatigue cracks initiate at the surface for relatively high-level stresses; for relatively low-level stresses fatigue cracks initiate at inclusions beyond the carburized case. After carburization, the ductility in the outmost 10 mu m of the carburized case has significantly reduced, leading to micro-crack occurrence during fatigue tests and associated relaxation of compressive residual stress in this region. Beyond this surface-adjacent region, no evident stress relaxation occurs due to the enhanced yield strength of the carburized case. The enhanced fatigue performance is mainly ascribed to the compressive residual compressive stress profile introduced by the carbon-concentration profile over the case. Moreover, solid solution strengthening by interstitially dissolved carbon contributes to improve the fatigue performance.

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