High-strength pearlitic steel rail having excellent delayed fracture properties
US8404178B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2007 |
| Grant date | Mar 26, 2013 |
| Priority date | — |
| Expiry date | May 2, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/18
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention provides a high-strength pearlitic steel rail, which is inexpensive, and has a tensile strength of 1200 MPa or more, and is excellent in delayed fracture properties. Specifically, the rail contains, in mass percent, C of 0.6 to 1.0%, Si of 0.1 to 1.5%, Mn of 0.4 to 2.0%, P of 0.035% or less, S of 0.0005 to 0.010%, and the remainder is Fe and inevitable impurities, wherein tensile strength is 1200 MPa or more, and size of a long side of an A type inclusion is 250 mm or less in at least a cross-section in a longitudinal direction of a rail head, and the number of A type inclusions, each having a size of a long side of 1 mm to 250 mm, is less than 25 per observed area of 1 mm2 in the cross-section in the longitudinal direction of the rail head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.