High strength bolt superior in delayed fracture resistant property and steel material for the same
US7070664B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2002 |
| Grant date | Jul 4, 2006 |
| Priority date | — |
| Expiry date | Oct 13, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D1/18
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high strength bold superior in delayed fracture resistant property has a bolt tensile strength of 1200 N/mm2. A high strength bolt comprised of a head portion and shaft portion formed by a steel material, wherein the relation between a bolt tensile strength TS (N/mm2) and tempering temperature T (° C.) satisfies the following expression (1), the relation between the bolt tensile strength TS (N/mm2) and the carbon equivalent Ceq (%) calculated from the chemical composition of the steel material used for the high strength bolt satisfies the following expression (2), and the tensile strength of the bolt is refined to a range of 1200 N/mm2 to 1600 N/mm2 by quenching and tempering:TS≦1.1T+850 (1)TS≦550Ceq+1000 (2)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.