Evaluation of Mn substitution for Ni in alumina-forming austenitic stainless steels

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Materials Science and Engineering A

DOI:https://doi.org/10.1016/j.msea.2009.06.043· OSTI ID:965848

Yamamoto, Yukinori ^[1]; Santella, Michael L ^[1]; Liu, Chain T ^[1]; Evans, Neal D ^[1]; Maziasz, Philip J ^[1]; Brady, Michael P ^[1]

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1. ORNL

There has been increasing interest in the substitution of low-cost Mn for Ni in austenitic stainless steels due to the rising price of Ni. This paper investigates the possibility of such a substitution approach for the recently developed alumina (Al{sub 2}O{sub 3})-forming austenitic (AFA) class of heat-resistant stainless steels. Computational thermodynamic tools were utilized to predict the alloy composition range to maintain an austenitic matrix microstructure when Mn is substituted for Ni in the presence of Al, which is a strong body-centered-cubic (BCC) phase stabilizer. Phase equilibria, oxidation behavior, and creep properties of Fe-(10-14)Cr-(5--15)Mn-(4-12)Ni-(2.5-3)Al-Cu-Nb-C-B (in weight percent) based alloys were studied. The alloys based on Fe-14Cr-2.5Al-(5-9)Mn-(10-12)Ni exhibited the best balance of oxidation and creep resistance, which represents approximately 50% reduction in Ni content compared to previously developed AFA alloys. These low-Ni, high-Mn AFA alloys formed protective Al{sub 2}O{sub 3} scales up to 973-1073 K in air and at 923 K in air with 10% water vapor. Creep-rupture lives of the alloys under a severe screening condition of 1023 K and 100 MPa were in the 7.2 x 10{sup 5}-1.8 x 10{sup 6} s (200-500 h) range, which is comparable to or somewhat improved over that of type 347 stainless steel (Fe-18Cr-11Ni base).

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Shared Research Equipment Collaborative Research Center
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 965848
• Journal Information: Materials Science and Engineering A, Vol. 524, Issue 1-2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
BCC LATTICES
CREEP
EVALUATION
MICROSTRUCTURE
OXIDATION
PRICES
STAINLESS STEELS
THERMODYNAMICS
WATER VAPOR