Effects of Gas Composition on the Characteristics of Surface Layers Produced on AISI316L Stainless Steel during Low Temperature Plasma Nitriding after Low Temperature Plasma Carburizing

Title & Authors
Effects of Gas Composition on the Characteristics of Surface Layers Produced on AISI316L Stainless Steel during Low Temperature Plasma Nitriding after Low Temperature Plasma Carburizing
Lee, In-Sup; Ahn, Yong-Sik;

Abstract
The 2-step low temperature plasma processes (the combined carburizing and post-nitriding) offer the increase of both surface hardness and thickness of hardened layer and corrosion resistance than the individually processed low temperature nitriding and low temperature carburizing techniques. The 2-step low temperature plasma processes were carried out for improving both the surface hardness and corrosion resistance of AISI 316L stainless steel. The influence of gas compositions on the surface properties during nitriding step were investigated. The expanded austenite ($\small{{\gamma}_N}$) was formed on all of the treated surface. The thickness of $\small{{\gamma}_N}$ and concentration of N on the surface increased with increasing both nitrogen gas and Ar gas levels in the atmosphere. The thickness of $\small{{\gamma}_N}$ increased up to about $\small{20{\mu}m}$ and the thickness of entire hardened layer was determined to be about $\small{40{\mu}m}$. The surface hardness was independent of nitrogen and Ar gas contents and reached up to about 1200 $\small{HV_{0.1}}$ which is about 5 times higher than that of untreated sample (250 $\small{HV_{0.1}}$). The corrosion resistance in 2-step low temperature plasma processed austenitic stainless steels was also much enhanced than that in the untreated austenitic stainless steels due to a high concentration of N on the surface.
Keywords
Plasma nitriding;Plasma carburizing;Expanded austenite;
Language
Korean
Cited by
1.
Duplex Stainless Steel의 저온 플라즈마 침질탄화시 Pulse Frequency 및 Duty Factor에 따른 표면 특성평가,천창석;이인섭;

한국표면공학회지, 2014. vol.47. 5, pp.221-226
1.
The Influence of Pulse Frequency and Duty Factor on Surface Characteristics during Low Temperature Plasma Nitrocarburizing Treatment of Duplex Stainless Steel, Journal of the Korean institute of surface engineering, 2014, 47, 5, 221
References
1.
T.-H. Lee, Y.-C. Jung, S.-J. Kim, J. Kor. Inst. Met. & Mater., 37 (1999) 400

2.
C. E. Pinedo, J. Vatavuk, S. D. de Oliveira, A. P. Tschiptschin. Mater. Sci. For., 318 (1999) 233

3.
Y. Sun, Mater. Proc. Tech., 168 (2005) 189

4.
Y. Sun, Mater. Letter., 59 (2005) 3410

5.
Y. Sun, E. Haruman, Vac., 81 (2006) 1

6.
Y. Sun, Mater. Sci. Eng., 404 (2005) 124

7.
Z. Cheng, C. X. Li, H. Dong, T. Bell, Surf. Coat. Tech., 191 (2005) 195

8.
K.-H. Jeong, I. S. Lee, J. Kor. Inst. Met. & Mater., 46 (2008) 125

9.
B. Larisch, U. Brusky, H.-J. Spies, Surf. & Coat. Tech., 116 (1999) 205

10.
H. Baba, T. Kodama, Y. Katada, Corrosion Science, 44 (2002) 2393