Carburizing austempering process
OwnerHuaxin Li, Shekhar G. Wakadeinventors
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Abstract
A novel combination of heat treatment steps includes the steps of carburizing a component fabricated of a medium carbon alloy steel at an elevated temperature for between three and six hours, subjecting the component to an austempering bath and holding it there for between fifteen and two hundred forty minutes and finally cooling the component to room temperature to allow martensitic transformation. These steps may be followed with cryogenic treatment to reduce retained austenite if needed. The process produces components with low distortion, high surface hardness, from HRC 56 to 62, and high surface compressive residual stress.
Claims18
A heat treatment process for a metal component, comprising the steps of:
- carburizing the metal component at an elevated temperature for between three and six hours,
- subjecting the component to an austempering bath for between fifteen minutes and four hours, and
- cooling the component to room temperature thereby allowing martensitic transformation.
A heat treatment process for a medium carbon alloy steel component, comprising the steps of:
- carburizing the medium carbon alloy steel component at an elevated temperature for between three and six hours,
- subjecting the component to an austempering bath for between fifteen minutes and four hours,
- cooling the component to room temperature thereby allowing martensitic transformation, and
- subjecting the component to a cryogenic bath to cool the component to a temperature of the cryogenic bath.
A heat treatment process for a medium carbon alloy steel component, comprising the steps of:
- carburizing a medium carbon alloy steel component at an elevated temperature for between three and six hours to produce a layer near a surface of the component having between 0.7% and 1.2% carbon,
- subjecting the component to an austempering bath for between fifteen minutes and four hours to produce bainite and retained austenite on and near the surface of the component, and
- cooling the component to room temperature thereby allowing martensitic transformation.
Dependencies are inferred from the claim text.