Method for heat treatment of steel
US6149734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 1998 |
| Grant date | Nov 21, 2000 |
| Priority date | — |
| Expiry date | Nov 27, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D1/18
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for the heat treatment of steel, comprising carburization hardening said steel, to form carburized steel, followed by a second hardening, reduces the grain size of steel while precipitating carbonitrides inside the grains of steel, thereby increasing the strength of the heat-treated steel. The carburization hardening comprises heating the steel to a first austenitic temperature range in an atmosphere comprising a carburizing gas and optionally ammonia, cooling the steel to a martensitic temperature range, and quenching the steel, and the second hardening comprises heating the carburized steel to a second austenitic temperature range in an atmosphere comprising a carburizing gas and ammonia, and quenching the steel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.