Method of producing hot-rolled steel sheet
US7879164B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 2010 |
| Grant date | Feb 1, 2011 |
| Priority date | — |
| Expiry date | Apr 27, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/009
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel sheet excellent in mechanical strength, workability and thermal stability and suited for use as a raw material in such fields of manufacturing automobiles, household electric appliances, machine structures, and of constructing buildings, and a manufacturing method thereof is provided. The steel sheet is a hot-rolled steel sheet of a carbon steel or low-alloy steel, the main phase of which is ferrite, and is characterized in that the average ferrite crystal grain diameter D(μm) at the depth of ¼ of the sheet thickness from the steel sheet surface satisfies the relations respectively defined by formulas (1) and (2) given below and the increase rate X (μm/min) in average ferrite crystal grain diameter at 700° C. at the depth of ¼ of the sheet thickness from the steel sheet surface and said average crystal grain diameter D(μm) satisfy the relation defined by the formula (3) given below:1.2≦D≦7 formula (1)D≦2.7+5000/(5+350·C+40·Mn)2 formula (2)D·X≦0.1 formula (3)wherein C and Mn represent the content (in % by mass) of the respective elements in the steel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.