Browse > Article
http://dx.doi.org/10.3740/MRSK.2017.27.8.431

Pit Corrosion of SS420 Stainless Steel by Grain Boundary Sensitization  

Choe, Byung Hak (Department of Advanced Metal & Materials Science Engineering, Gangneung-Wonju National Univ.)
Lee, Bum Gyu (Department of Advanced Metal & Materials Science Engineering, Gangneung-Wonju National Univ.)
Jang, Hyeon Su (Department of Advanced Metal & Materials Science Engineering, Gangneung-Wonju National Univ.)
Park, Chan Sung (Forensic Engineering Dept., National Forensic Service)
Kim, Jin Pyo (Forensic Engineering Dept., National Forensic Service)
Park, Nam Gyu (Forensic Engineering Dept., National Forensic Service)
Kim, Cheong In (CRA Piping Korea)
Kim, Bo Mi (HMW Co., Ltd.)
Publication Information
Korean Journal of Materials Research / v.27, no.8, 2017 , pp. 431-437 More about this Journal
Abstract
This study investigated the surface pit corrosion of SS420J2 stainless steel accompanied by intergranular crack. To reveal the causes of surface pits and cracks, OM, SEM, and TEM analyses of the microstructures of the utilized SS420J2 were performed, as was simulated heat treatment. The intergranular cracks were found to have been induced by a grain boundary carbide of $(Cr,Fe)_{23}C_6$, which was identified by SEM/EDS and TEM diffraction analyses. The mechanism of grain boundary sensitization occurred at the position of the carbide, followed by its occurrence at the Cr depleted zone. The grain boundary carbide of $(Cr,Fe)_{23}C_6$ type precipitated during air cooling condition after a $1038^{\circ}C$ solid solution treatment. The carbide precipitate formation also accelerated at the band structure formed by cold working. Therefore, using manufacturing processes of cooling and cold working, it is difficult to protect SS420J2 stainless steel against surface pit corrosion. Several counter plans to fight pit corrosion by sensitization were suggested, involving alloying and manufacturing processes.
Keywords
stainless steel; pit; intergranular crack; grain boundary sensitization; carbide precipitation;
Citations & Related Records
연도 인용수 순위
  • Reference
1 AK Steel Corporation, Product Data Sheet of 420 Stainless Steel, 420-S- 08-01-07 (2007).
2 L. D. Barlow and M. Du Toit, J. Mater. Eng. Performance, 21, 1327 (2012).   DOI
3 C. M. Garzon, A. Toro and A. P. Tschiptschin, Trans. Indian Inst. Met., 55, 255 (2003).
4 S. Teraoka, M. Fukuda, M. Kobayashi, A. Takahashi and M. Takemoto, Nippon Still Technical Rep., 99, 39 (2010).
5 D. Lopez, J. P. Congote, A. Toro and A. P. Tschiptschin, Wear, 259, 118 (2005).   DOI
6 A. Toro. A. Sinatora, D, K. Tanaka and A. P. Tschiptschin, Wear, 251, 1257 (2001).   DOI
7 D. H. Mesa, A. Toro, A. Sinatora and A. P. Tschiptschin, Wear, 255, 139 (2003).   DOI
8 R. Stickler and A. Vinckier. Trans. ASM, 54, 362 (1961).
9 C. Stawstrom and M. Hillert, J. Iron Steel Inst., 207, 77 (1969).
10 C. S. Tedmon, D. A. Vermilyea and J. H. Rosolowski, J.Electrochemical Soc., 118, 192 (1971).   DOI
11 G. H. Aydo du and M. K. Aydinol, Corrosion Sci., 48, 3565 (2006).   DOI
12 A. Joshi and D. Ff Stein, Corrosion, 28, 321 (1972).   DOI
13 G. Hebsleb, Werkst Korros., 33, 334 (1982).   DOI
14 J. E. Truman, Proc. UK Corrosion, 87, 111 (1987).