Title: Numerical analysis of stress-induced and concentration-dependent carbon diffusion in low-temperature surface carburisation of 316L stainless steel

Authors: Yawei Peng; Jianming Gong; Yong Jiang; Dongsong Rong; Minghui Fu

Addresses: School of Mechanical and Power Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, China; Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, No. 30 Puzhu South Road, Nanjing 211816, China ' School of Mechanical and Power Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, China; Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, No. 30 Puzhu South Road, Nanjing 211816, China ' School of Mechanical and Power Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, China; Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, No. 30 Puzhu South Road, Nanjing 211816, China ' School of Mechanical and Power Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, China; Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, No. 30 Puzhu South Road, Nanjing 211816, China ' School of Mechanical and Power Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing 211816, China; Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, No. 30 Puzhu South Road, Nanjing 211816, China

Abstract: A kinetic model based on stress-induced and concentration-dependent carbon diffusion was developed for simulating the carbon concentration-depth profile of carburised austenitic stainless steel. The model considers that the carbon diffusivity is dependent of carbon concentration and the stress induced by diffusion of the dissolved carbon atoms can affect the diffusion behaviour in turn. The results show that in carburised 316L stainless steel, the calculated carbon concentration-depth profile is in good agreement with experimental results, which indicates that the stress and concentration-dependent diffusivity play important roles in carbon diffusion. As a result of carburisation, large compressive residual stress is generated and gradiently distributes in the carburised layer, meanwhile, the diffusion of carbon atoms can be accelerated by stress. Although, the compressive residual stress is not the dominant reason for total carbon diffusivity increases significantly with increasing carbon concentration, as the next driving force it cannot be ignored during low-temperature surface carburisation.

Keywords: austenitic stainless steels; ASS; low-temperature surface carburisation; carbon diffusion; concentration-dependent diffusivity; stress-induced diffusion.

DOI: 10.1504/IJCMSSE.2019.101663

International Journal of Computational Materials Science and Surface Engineering, 2019 Vol.8 No.1, pp.27 - 36

Accepted: 10 Nov 2018
Published online: 14 Aug 2019 *

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