Cr-W-V bainitic/ferritic steel with improved strength and toughness and method of making
AssigneeMartin Marietta Energy Systems, Inc.
InventorsRonald L. Klueh, Philip J. Maziasz
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Abstract
A high strength, high toughness Cr-W-V ferritic steel composition suitable for fast induced-radioactivity (FIRD) decay after irradiation in a fusion reactor comprises 2.5-3.5 wt % Cr, 2. This invention was made with Government support under contract DE-AC05-840R21400 awarded by the U.S. Department of Energy to Martin Marietta Energy Systems, Inc. and the Government has certain rights in this invention.
Claims20
A high strength, high toughness bainitic/ferritic steel alloy comprising about 2.75% to 4.0% chromium, about 2.0% to 3.5% tungsten, about 0.10% to 0.30% vanadium, and about 0.1% to 0.15% carbon with the balance iron, wherein the percentages are by total weight of the composition, wherein the alloy having been heated to an austenitizing temperature and then cooled at a rate sufficient to produce carbide-free acicular bainite.
A method of producing a high strength, high toughness ferritic steel composition comprising the steps of:
- forming a body of a ferritic steel composition comprising 2.75wt % to 4.0wt % chromium, 2.0wt % to 3.5wt % tungsten, 0.10wt % to 0.30wt % vanadium, and 0.1 wt % to 0.15wt % carbon with the balance iron;
- heating the body to an austenitizing temperature for a predetermined length of time;
- and
- cooling the body at a rate sufficient to produce carbide-free acicular bainite.
A method of producing a high strength, high toughness ferritic steel alloy comprising the steps of:
- forming a body of a ferritic steel composition comprising 2.75wt % to 4.0wt % chromium, 2.0 wt % to 3.5wt % tungsten, 0.10wt % to 0.30wt % vanadium, 0.1 wt % to 0.15wt % carbon, 0.003wt % to 0.009wt % boron, 0.05wt % to 0.15wt % tantalum and 0.0 to 0.2wt % titanium, 0-0.5wt % Mo, 0.2-0.5wt % Si, 0-0.5wt % Mn, 0.0-0.03wt % N, 0.05-0.25wt % Nb, 30 and 0-0.25wt % Cu;
- heating said composition to an austenitizinq temperature;
- and
- cooling said composition at a rate to form a carbide-free acicular bainite microstructure;
- an
- tempering said composition at a temperature of not more than about 700.degree. C. for not more than 1 hour.
Dependencies are inferred from the claim text.