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US 6,884,306 B1Granted
Baintic steel
AssigneeQinetiq Limited
InventorsKankanange J A Mawella, Francisca G Caballero, Harshad K D H Bhadeshia
Life of this patent
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Abstract
A mainly bainitic steel having the following composition in weight percent: carbon 0.6-1.1; silicon 1.5 to 2.0; manganese 1.8 to 4.0; chromium 1.2 to 1.4; nickel 0-3; molybdenum 0.2 to 0.5; vanadium 0.1 to 0.2, balance iron save for incidental impurities.
Claims2
A method of heat treating a steel to produce a mainly bainitic structure, wherein the steel has the following composition in weight percent;
- carbon 0.6-1.1;
- silicon 1.5 to 2.0;
- manganese 1.8 to 4.0;
- chromium 1.2 to 1.4;
- nickel 0-3;
- molybdenum 0.2 to 0.5;
- vanadium 0.1 to 0.2,
- balance iron save for incidental impurities;
- and,
- wherein the method comprises the steps of:
- homogenising the steel at a temperature of at least 1150° C. for at least 24 hours;
- air cooling the steel;
- subjecting the steel to a temperature between 900° C. and 1000° C.;
- isothermally transforming the steel at a temperature between 190° C. and 260° C. for 1 to 3 weeks.
11 more elements
A method of heat treating a steel to produce a mainly bainitic structure, wherein the steel has the following composition in weight percent:
- carbon 0.7 to 0.9;
- silicon 1.5 to 1.7;
- manganese 1.9 to 2.2;
- chromium 1.25 to 1.4;
- nickel 0 to 0.05;
- molybdenum 0.25 to 0.35;
- vanadium 0.1 to 0.15,
- balance iron save for incidental impurities;
- and,
- wherein the method comprises the steps of:
- homogenising the steel at a temperature of at least 1150° C. for at least 24 hours;
- air cooling the steel;
- subjecting the steel to a temperature between 900° C. and 1000° C.;
- and,
- isothermally transforming the steel at a temperature between 190° C. and 260° C. for 1 to 3 weeks.
12 more elements
Dependencies are inferred from the claim text.