"Method of fabricating ""TRIP"" steel in the form of thin strip, and thin strip obtained in this way"
US6328826A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 2000 |
| Grant date | Dec 11, 2001 |
| Priority date | — |
| Expiry date | Jul 21, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/002
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention provides a method of fabricating "TRIP" steel in the form of thin strip, wherein: PA1 a strip from 1.5 to 10 mm thick, preferably from 1 to 5 mm thick, is cast directly from liquid steel having the composition (in weight percent) C % from 0.05 to 0.25, (Mn+Cu+Ni) % from 0.5 to 3, (Si+Al) % from 0.1 to 4, (P+Sn+As+Sb) % not greater than 0.1, (Ti+Nb+V+Zr+rare earths) % less than 0.3, Cr % less than 1, Mo % less than 1, V % less than 1, the remainder being iron and manufacturing impurities; PA1 said strip is hot rolled on-line in one or more passes at a temperature higher than the Ar.sub.3 temperature of said steel and with a reduction ratio from 25 to 70%; PA1 first forced cooling of said strip is carried out at a cooling rate from 5 to 100.degree. C./s; PA1 the strip remains at temperatures from 550 to 400.degree. C. for the time needed for bainitic transformation to occur therein with a residual austenite content greater than 5%, while preventing the formation of perlite, after which the transformation is interrupted by second forced cooling of said strip to a temperature below 400.degree. C.; and PA1 said strip is coiled at a temperature below 350.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.