Steel for machine structural use
US6797231B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 2002 |
| Grant date | Sep 28, 2004 |
| Priority date | — |
| Expiry date | Mar 27, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C38/60
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention provides a steel for machine structural use, which is excellent in machinability, comprising, in percent by mass, C: 0.1-0.6%. Si: 0.01-2.0%, Mn: 0.2-2.0%, S: 0.005-0.2%, Al: not more than 0.009%, Ti: not less than 0.001% but less than 0.04%, Ca: 0.0001-0.01%, O (oxygen): 0.0010-0.01%, and N: not more than 0.02% and satisfying the following relations (1) to (3):n0/S (%)≧2500  (1)n1/n0≦0.1  (2)n2≧10  (3)where n0: total number of sulfide inclusions not smaller than 1 &mgr;m per mm2 of a cross section parallel to the direction of rolling (number/mm2); n1: number of MnS inclusions having not smaller than 1 &mgr;m and containing not less than 1.0% of Ca per mm2 of a cross section parallel to the direction of rolling (number/mm2); n2: number, per mm2 of a cross section parallel to the direction of rolling, of oxide inclusions having a specific composition comprising CaO—Al2O3—SiO2—TiO2 and having a diameter of not less than 1 &mgr;m (number/mm2).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.