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http://dx.doi.org/10.5781/KWJS.2010.28.3.092

Microstructures and Hardness of Al-Si Coated 11%Cr Ferritic Stainless Steel, 409L GTA Welds  

Park, Tae-Jun (Dept. of Material Science and Engineering, Pusan National University)
Kong, Jong-Pan (Dept. of Material Science and Engineering, Pusan National University)
Na, Hye-Sung (Dept. of Material Science and Engineering, Pusan National University)
Kang, Chung-Yun (Dept. of Material Science and Engineering, Pusan National University)
Uhm, Sang-Ho (Technical Research Laboratories, POSCO)
Kim, Jeong-Kil (Technical Research Laboratories, POSCO)
Woo, In-Su (Technical Research Laboratories, POSCO)
Lee, Jong-Sub (Technical Research Laboratories, POSCO)
Publication Information
Journal of Welding and Joining / v.28, no.3, 2010 , pp. 92-98 More about this Journal
Abstract
Ferritic stainless steels, which have relatively small thermal expansion coefficient and excellent corrosion resistance, are increasingly being used in vehicle manufacturing, in order to increase the lifetime of exhaust manifold parts. But, there are limits on use because of the problem related to cosmetic resistance, corrosions of condensation and high temperature salt etc. So, Aluminum-coated stainless steel instead of ferritic stainless steel are utilized in these parts due to the improved properties. In this investigation, Al-8wt% Si alloy coated 409L ferritic stainless steel was used as the base metal during Gas Tungsten Arc(GTA) welding. The effects of coated layer on the microstructure and hardness were investigated. Full penetration was obtained, when the welding current was higher than 90A and the welding speed was lower than 0.52m/min. Grain size was the largest in fusion zone and decreased from near HAZ to base metal. As welding speed increased, grain size of fusion zone decreased, and there was no big change in HAZ. Hardness had a peak value in the fusion zone and decreased from the bond line to the base metal. The highest hardness in the fusion zone resulted from the fine re-precipitation of the coarse TiN and Ti(C, N) existed in the base metal during melting and solidification process and the presence of fine $Al_2O_3$ and $SiO_2$ formed by the migration of the elements, Al and Si, from the melted coating layer into the fusion zone.
Keywords
Ferritic stainless steel; Aluminized stainless steel; GTAW; Microstructure; Hardness;
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  • Reference
1 T. B. Reed, Free Energy of Formation of Binary Compounds, MIT Press, Cambridge, MA(1971)
2 Donaldson Company, Product Literature, Medium- and Heavy-Duty Exhaust Products, 2007, 147
3 The corrosion resistance properties of weather resistant alstar, Nisshin Steel Technical information
4 I.S Woo, W.B Lee, J.G Kim, S.H Uhm, J.B Lee, Improvement of Low Temperature Formability in 11Cr Ferritic Stainless Steel GTA Welds, Proceeding of Autumn Meeting of KWJS, 48 (2007), 135-137 (in Korean)
5 Aluminized Steel Type1 Stainless 409 and 439, Ak steel corporation product data, Alum-409-439-B-08-01-07 (2007)
6 S. R. Shatynski, Oxid. Met., 13, 105(1979)   DOI