High tensile strength hot-rolled steel sheet
US6425963B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 2000 |
| Grant date | Jul 30, 2002 |
| Priority date | — |
| Expiry date | Jan 24, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/04
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
High tensile strength hot-rolled steel sheet suitable for use in interior materials for automobiles and a method for producing the same, in which bake hardenability, fatigue resistance, crash resistance, and resistance to room temperature aging are improved, containing 0.01% to 0.12% by weight of carbon, 2.0% by weight or less of silicon, 0.01% to 3.0% by weight of manganese, 0.2% by weight or less of phosphorus, 0.001% to 0.1% by weight of aluminum, and 0.003% to 0.02% by weight of nitrogen and subjected to hot rolling and cooling at a cooling rate of 50° C./s or more within 0.5 second after hot rolling; the hot-rolled steel sheet has a structure including a ferrite having an average grain diameter of 8 &mgr;m or less as a primary phase, the amount of solute Nitrogen ranges from 0.003% to 0.01%, and the ratio, Ngb/Ng, of an average concentration Ngb of nitrogen dissolved in the ferrite grain boundary to an average concentration Ng of nitrogen dissolved in ferrite grains ranges from 100 to 10,000.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.