Exhaust emission regulations of the automotive are enforced in each country to prevent air pollution and global warming, and the restriction standard tends to become severer. Various techniques such as the combustion improvement of gasoline, upgrades of the catalyst, and the thermal capacity decreases in the exhaust lines are adopted to suit the regulations, and these lead to an increase of the maximum temperature of the exhaust gas. Recently, ferritic stainless steels are mainly used to parts of exhaust lines, as their thermal expansion coefficient is small, and the cyclic oxidation resistance and the thermal fatigue property are better than austenitic stainless steels. This paper presents newly developed heat-resistant stainless steels from Nisshin Steel for exhaust lines usage, and describes the currents of the steel development that could be envisaged in the future. With regard to improving the high-temperature strength of ferritic stainless steels, the addition of Nb, Mo and Cu is effective in solution hardening and precipitation hardening at 700 °C, while the addition of Nb, Mo and W is effective in mainly solution hardening at 900 °C. The addition of Cr, Si and Mn suppress the breakaway oxidation in air at 950 °C up to 200 h of ferritic stainless steels containing 14% Cr. Especially, the addition of 0.8% or higher Mn would effectively improve the adherence of oxide scale. It is confirmed that ferritic stainless steels, NSSHR-1 (14Cr-1Mn-0.9Si-Nb) and NSSHR-2 (10Cr-0.9Si-Nb-Ti), is having a superior heat resistance, formability and cost performance compared to conventional Type441 and Type439, respectively.


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    Titel :

    Development of heat-resistant ferritic stainless steels for exhaust lines in Nisshin Steel


    Weitere Titelangaben:

    Entwicklung von hitzebeständigen ferritischen nichtrostenden Stählen für Auspuffanlagen bei Nisshin Steel


    Beteiligte:
    Oku, Manabu (Autor:in)


    Erscheinungsdatum :

    2010


    Format / Umfang :

    8 Seiten, 12 Bilder, 4 Tabellen, 27 Quellen


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Datenträger


    Sprache :

    Englisch





    Development of ferritic stainless steels for automotive exhaust systems

    Alves, H.J.B. / Carvalho, J.A.N. / Aquino, M.V. et al. | Tema Archiv | 2002


    Heat-resistant ferritic stainless steel with high formability for automotive exhaust gas systems

    Miyazaki,A. / HIrasawa,J. / Gunji,M. et al. | Kraftfahrwesen | 2002



    Heat-Resistant Ferritic Stainless Steel with High Formability for Automotive Exhaust Gas Systems

    Miyazaki, Atsushi / Hirasawa, Junichiro / Gunji, Makio et al. | SAE Technical Papers | 2002