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Heat treated 9 Cr-1 Mo steel material for high temperature application

United States Patent

August 21, 2012
View the Complete Patent at the US Patent & Trademark Office
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Improved Martensitic Steel for High Temperature Applications
The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.
Jablonski; Paul D. (Salem, OR), Alman; David (Corvallis, OR), Dogan; Omer (Corvallis, OR), Holcomb; Gordon (Albany, OR), Cowen; Christopher (Albany, OR)
The United States of America, as represented by the United States Department of Energy (Washington, DC), N/A (
12/ 209,488
September 12, 2008
STATEMENT OF GOVERNMENTAL SUPPORT The United States Government has rights in this invention pursuant to the employer-employee relationship of the Government to the inventors as U.S. Department of Energy employees and site-support contractors at the National Energy Technology Laboratory.