Process for manufacturing a high strength rail
US4810311A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 9, 1987 |
| Grant date | Mar 7, 1989 |
| Priority date | — |
| Expiry date | Jul 9, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D9/04
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Starting from a temperature at or above the A.sub.3 transformation point of the steel of the rail, the head of the rail is cooled to a temperature not lower than the Ms point at a rate lower than the critical quenching rate so that the head acquires a fine perlitic structure. Simultaneously the web is superficially cooled to the Ms point or below, at a rate greater than the head, so as to obtain a surface layer of martensite and/or bainite, and the surface cooling is controlled so that, at the end of controlled cooling, internal portions of the web not transformed to martensite and/or bainite retain sufficient heat to temper the surface layer during subsequent cooling to ambient temperature. At the same time the flange of the rail is cooled at a rate ensuring straightness of the rail.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.