Long-Term Oxidation of Candidate Cast Iron and Stainless Steel Exhaust System Alloys from 650 to 800 °C in Air with Water Vapor
The oxidation behavior of candidate cast irons and cast stainless steels for diesel exhaust systems was studied for 5,000 h at 650–800 °C in air with 10 % H2O. At 650 °C, Ni-resist D5S exhibited moderately better oxidation resistance than did the SiMo cast iron. However, the D5S suffered from oxide scale spallation at 700 °C, whereas the oxide scales formed on SiMo cast iron remained relatively adherent from 700 to 800 °C. The oxidation of the cast chromia-forming austenitics trended with the level of Cr and Ni additions, with small mass losses consistent with Cr oxy-hydroxide volatilization for the higher 25Cr/20–35Ni HK and HP type alloys, and transition to rapid Fe-base oxide formation and scale spallation in the lower 19Cr/12Ni CF8C plus alloy. In contrast, small positive mass changes consistent with protective alumina scale formation were observed for the cast AFA alloy under all conditions studied. Implications of these findings for exhaust system components are discussed.
KeywordsWater vapor Exhaust Cast iron Austenitic Oxidation
The authors thank Duraloy Technologies, Inc. for providing cast austenitic stainless steels TMA 4705, TMA 6301, HP, and HK materials for study. T. Lowe, M. Stephens, G. Garner, and T. Jordan are thanked for experimental work and A. Shyam, S. Dryepondt, and B Pint for helpful comments on this manuscript. Research sponsored by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, Propulsion Materials Program (managed by J. Gibbs).
- 1.D. Li and C. Sloss, Ferrous high-temperature alloys for exhaust component applications. SAE International Journal of Material and Manufacturing 3, (1), 391–404 (2010).Google Scholar
- 2.D. Li, C. Sloss and S. Amer Foundry, Cast ferritic stainless steels for automotive exhaust components. Transactions of the American Foundry Society 121, 487–494 (2013).Google Scholar
- 3.K. Dawi, J. Favergeon, and G. Moulin, High temperature corrosion of the Si-Mo cast iron in exhaust atmosphere. High Temperature Corrosion and Protection of Materials 7, Pts 1 and 2 595–598, 743–751 (2008).Google Scholar
- 5.Y. L. Yang, Z. Y. Cao, Y. Qi, and Y. B. Liu, The study on oxidation resistance properties of ductile cast irons for exhaust manifold at high temperatures, in Manufacturing Science and Engineering, Pts 1–5, vol. 97–101. Advanced Materials Research, eds. Z. Jiang, and C. L. Zhang (Trans Tech Publications, Switzerland, 2010), pp. 530–533.Google Scholar
- 8.F. Tholence and M. Norell, High temperature corrosion of cast irons and cast steels in dry air, in High Temperature Corrosion and Protection of Materials 5, eds. by R. Streiff, I. G. Wright, R. C. Krutenat, M. Caillet, A. Galerie, Pts 1 and 2, vol. 369–373. Materials Science Forum, (Trans Tech Publications, Switzerland, 2001), pp. 197–204.Google Scholar
- 13.J. B. Heywood, Internal Combustion Engines Fundamentals. McGraw-Hill Mechanical Engineering. ISBN: 9780070286375 (1988).Google Scholar
- 19.R. I. Pankiw, G. Muralidharan, and V. K. Sikka, Development of stronger and more reliable cast austenitic stainless steels (H-series) based on scientific and design methodology 2006-06-30, OSTI ID: 886136, ORNL/TM-2006/45 (2006).Google Scholar
- 20.R. I. Pankiw, G. Muralidharan, V. K. Sikka, and P. J. Maziasz, Cast heat-resistant austenitic steel with improved temperature creep properties and balanced alloying element additions and methodology for development of the same, US patent 8,318,083 (Nov 27, 2012).Google Scholar
- 21.G. Muralidharan, V. K. Sikka, P. J. Maziasz, and R. I. Pankiw, Cast, heat-resistant austenitic stainless steels having reduced alloying element content, US Patent US 7,749,432 (Jul 6, 2010).Google Scholar
- 22.G. Muralidharan, V. K. Sikka, P. J. Maziasz, and R. I. Pankiw, Cast, heat-resistant austenitic stainless steels having reduced alloying element content, US Patent 8,003,045 (Aug 23, 2011).Google Scholar
- 23.G. Muralidharan, Y. Yamamoto, and M. P. Brady, Cast alumina forming austenitic stainless steels. US Patent 8,431,072 (April 30, 2013).Google Scholar
- 24.G. Muralidharan, Y. Yamamoto, and M. P. Brady, submitted.Google Scholar
- 25.B. A. Pint, J. P. Shingledecker, M. P. Brady, and P. J. Maziasz, Proceedings of GT2007 ASME Turbo Expo 2007: Power for Land, Sea, and Air May 14–17 (Montreal, Canada, 2007), 3, 995–1002 (2007).Google Scholar
- 26.E. J. Opila, Volatility of common protective oxides in high-temperature water vapor: Current understanding and unanswered questions, in High Temperature Corrosion and Protection of Materials 6, Prt 1 and 2, Proceedings, vol. 461–464. Materials Science Forum, eds. P. Steinmetz, I. G. Wright, G. Meier, A. Galerie, B. Pieraggi, and R. Podor (2004).Google Scholar
- 34.R. Covert, J. Morrison, and K. Rohrig, Properties and applications of Ni-resist and ductile Ni-resist alloys. Publisher: Nickel Development Institute (1998) http://www.nickelinstitute.org/~/Media/Files/TechnicalLiterature/PropertiesandApplicationsofNi_ResistandDuctileNi_ResistAlloys_11018_.pdf.
- 35.F. Cverna, Thermal Expansion ASM Ready Reference: Thermal Properties of Metals, (ASM International, Materials Park, 2002).Google Scholar