Rolled round steel material for steering rack bar, and steering rack bar
US9976206B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 2014 |
| Grant date | May 22, 2018 |
| Priority date | — |
| Expiry date | Mar 16, 2035 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P10/25
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A rolled round steel material contains C: 0.38 to 0.55%, Si: 1.0% or less, Mn: 0.20 to 2.0%, S: 0.005 to 0.10%, Cr: 0.01 to 2.0%, Al: 0.003 to 0.10%, B: 0.0005 to 0.0030%, Ti: 0.047% or less, Cu: 0 to 1.0%, Ni: 0 to 3.0%, Mo: 0 to 0.50%, Nb: 0 to 0.10%, V: 0 to 0.30%, Ca: 0 to 0.005%, and Pb: 0 to 0.30%, a remaining portion being constituted by Fe and an impurities, the impurities containing P in an amount of 0.030% or less and N in an amount of 0.008% or less, and has a chemical composition satisfying [3.4N≤Ti≤3.4N+0.02]. The microstructure is constituted by ferrite (F), lamellar pearlite (LP), and cementite (C) and microstructural features vary in terms of the lateral, longitudinal and central portions of the steel. This steel material has a high base material toughness and good machinability without performing thermal refining.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.