Wire rod for non heat-treated mechanical part, steel wire for non heat-treated mechanical part, and non heat-treated mechanical part
US10457998B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 2016 |
| Grant date | Oct 29, 2019 |
| Priority date | — |
| Expiry date | Oct 15, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/009
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel wire for a non heat-treated mechanical part includes, as a chemical composition, by mass %, a predetermined amount of C, Si, Mn, Cr, Mo, Ti, Al, B, Nb, and V, and limited P, S, N, and O and a remainder of Fe and impurities; in which a structure includes, by volume %, a bainite of greater than or equal to 75×[C %]+25, and a remainder of one or more of a ferrite and a pearlite when an amount of C is set to [C %] by mass %; when an average aspect ratio of a bainite block in a second surface layer area of the steel wire is set as R1, the R1 is greater than or equal to 1.2; when an average grain size of a bainite block in a third surface layer area of the steel wire is set to PS3 μm, and an average grain size of a bainite block in a third center portion of the steel wire is set to PC3 μm, the PS3 satisfies Expression (c), and the PS3 and the PC3 satisfy Expression (d), a standard deviation of a grain size of the bainite block in the structure is less than or equal to 8.0 μm; and a tensile strength is in a range of 800 MPa to 1600 MPa, PS3≤20/R1 (c),PS3/PC3≤0.95 (d).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.