Coated seizure-hardening type cold-rolled steel sheet having excellent aging resistance and method of production thereof
US6171412A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1998 |
| Grant date | Jan 9, 2001 |
| Priority date | — |
| Expiry date | Nov 25, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D8/0473
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed are bake-hardenable sheet steel with good anti-aging property and a method for producing it. While controlling its C, P, S and N contents, the chemical composition of the sheet steel is defined to comprise not larger than 1.0% of Si, not larger than 3.0% of Mn, from 0.01 to 0.20% of Al and from 0.001 to 0.2% of Ti, in terms of % by weight. The value A (=(AI.sub.QUENCH -AI)/AI.sub.QUENCH) of the sheet steel is defined to be not smaller than 0.4 and the value AI.sub.QUENCH thereof to be not smaller than 30; or the ratio of the mean misorientation, M (degree), to the mean grain size, G (.mu.m), M/G, of the sheet steel is defined to be not smaller than 0.8. The steel may additionally contain from 0.001 to 0.2% of Nb and/or from 0.0001 to 0.0080% of B. While controlling its Si, Mn, S, Al and N contents, the chemical composition of a steel slab is defined to comprise from 0.005 to 0.02% of C, not larger than 0.05% of P and from 0.025 to 0.19% of Nb, with satisfying the condition of 0.7.times.(C/12).ltoreq.Nb/93.ltoreq.1.2.times.(C/12) (where C indicates the C content (wt. %), and Nb indicates the Nb content (wt. %)). To produce bake-hardenable sheet steel from it, the slab is h…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.