Oxidation resistant high creep strength austenitic stainless steel

US7744813B2 · kind B2 · utility

Assignee

• UT-BATTELLE, LLC · US

Inventors

• Michael P. Brady · Oak Ridge, US
• Bruce A. Pint · Knoxville, US
• Chain T. Liu · Oak Ridge, US
• Philip J. Maziasz · Oak Ridge, US
• Yukinori Yamamoto · Tokyo, JP
• Zhao Lu · Fort Collins, US

Key dates

• Filing date: Jan 4, 2007
• Grant date: Jun 29, 2010
• Expiry date: Jul 23, 2027

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C38/48
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

An austenitic stainless steel displaying high temperature oxidation and creep resistance has a composition that includes in weight percent 15 to 21 Ni, 10 to 15 Cr, 2 to 3.5 Al, 0.1 to 1 Nb, and 0.05 to 0.15 C, and that is free of or has very low levels of N, Ti and V. The alloy forms an external continuous alumina protective scale to provide a high oxidation resistance at temperatures of 700 to 800° C. and forms NbC nanocarbides and a stable essentially single phase fcc austenitic matrix microstructure to give high strength and high creep resistance at these temperatures.