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US 6,309,474 B1Granted
Process for producing maraging steel
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorToru Yagasaki
Life of this patent
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Abstract
In a method for producing maraging steel, a thin plate of maraging steel is subjected to an aging treatment, is then subjected to a fluoridation processing in which the thin plate is heated and maintained in a fluoric reacting gas including fluorine so as to form a fluoride layer on a surface of the thin plate, and is then subjected to nitriding in a nitriding reaction gas including ammonia gas so as to restrict the carbon concentration of the thin plate after the nitriding to 2 weight % or less.
Claims9
A method for producing maraging steel comprising:
- performing solution treatment in a vacuum furnace to a thin plate made from maraging steel;
- aging the thin plate in an inert gas;
- performing fluoridation processing by heating and maintaining the thin plate in a, fluoric reacting gas including fluorine so as to form a fluoride layer on a surface of the thin plate;
- and then
- nitriding the thin plate in a nitriding reaction gas including ammonia gas so as to restrict the carbon concentration of the thin plate after the nitriding at 2 weight % or less;
- wherein the nitriding reaction gas includes no or very low amounts of carbon.
3 more elements
A method for producing maraging steel comprising:
- aging a thin plate made from maraging steel;
- performing fluoridation processing by heating and maintaining the thin plate in a fluoric reacting gas including fluorine so as to form a fluoride layer on a surface of the thin plate;
- and then,
- nitriding the thin plate in a nitriding reaction gas including ammonia gas so as to restrict the carbon concentration of the thin plate after the nitriding at 2 weight % or less;
- calculating the maximum size of inclusions included in the maraging steel by using a statistics extremes method;
- evaluating the inclusions in the maraging steel to select the maraging steel;
- wherein a sample of maraging steel is dissolved in a solution;
- only the inclusions remain in the solution;
- the inclusions in the solution are screened by a filter so as to remove smaller inclusions;
- the inclusion remaining on the filter are sampled;
- and
- the maximum size of the inclusions is calculated based on the statistics extremes method.
9 more elements
Dependencies are inferred from the claim text.