Galvanized high-strength steel sheet having low yield ratio and method of producing the same
US5180449A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 1992 |
| Grant date | Jan 19, 1993 |
| Priority date | — |
| Expiry date | Jan 16, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12799
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A galvanized steel sheet is provided which has a tensile strength of not less than 80 kgf/mm.sup.2 and a yield ratio of not more than 60%, and which is applicable to members of an automobile body, particularly those requiring strength. By appropriately controlling the amounts of components, such as C, Mn, Nb, Ti and B, the structure of the steel sheet is formed into a dual-phase structure having a second phase strucutre. The steel sheet is recrystallization-annealed, galvanized while it is maintained at a temperature range near 500.degree. C., and then is cooled. By controlling the rate of cooling the steel sheet, the second phase structure generated is prevented from hardening more than necessary. A galvanized high-strength steel sheet is obtained which has a low yield ratio and excellent stretch-flanging properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.