Building construction steel having excellent fire resistance and low yield ratio
US5147474A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1990 |
| Grant date | Sep 15, 1992 |
| Priority date | — |
| Expiry date | Nov 13, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31678
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed is a process for manufacturing a building construction steel having excellent high-temperature characteristics, which can be marketed at an economically reasonable price. According to this process, a slab having a steel composition in which appropriate amounts of Mo and Nb are added to a low-C and low-Mn steel is heated at a high temperature and rolling is finished at a relatively high temperature, or a slab having a steel composition in which an appropriate amount of Mo is added to a low-C and low-Mn steel composition is heated at a high temperature, rolling is finished at a relatively high temperature, and at the subsequent air-cooling step, water cooling is started at a temperature of a ferrite fraction of 20 to 50% during the transformation from austenite to ferrite, water cooling is carried out to an arbitrary temperature lower than 550.degree. C., followed by air cooling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.