Steering rack comprising steel bar with rack teeth
US7662245B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2004 |
| Grant date | Feb 16, 2010 |
| Priority date | — |
| Expiry date | Aug 15, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/1967
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A steel bar for a steering rack that contains 0.50 to 0.60% by mass of C, 0.05 to 0.5% by mass of Si, 0.2 to 1.5% by mass of Mn, 0.0005 to 0.003% by mass of B, 0.005 to 0.05% by mass of Ti, 0.0005 to 0.1% by mass of Al, and 0.002 to 0.02% by mass of N is provided. Given D as a diameter of the steel bar, then the steel bar is adjusted in such a manner that quenched and tempered structures in a portion of the steel bar at a depth of D/4 from a surface satisfy conditions I), II), and III) as follows: I) a sum of a tempered bainitic structure and a tempered martensitic structure accounts for 30 to 100% in area percentage; II) a regenerated perlite structure accounts for 0 to 50% in area percentage; and III) a sum of the tempered bainitic structure, the tempered martensitic structure, and the regenerated perlite structure accounts for 50 to 100% in area percentage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.