Electric resistance welded steel pipe for torsion beam
US11028456B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 2017 |
| Grant date | Jun 8, 2021 |
| Priority date | — |
| Expiry date | Jan 17, 2038 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/005
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An electric resistance welded steel pipe for a torsion beam, in which a base metal portion includes, in terms of % by mass, 0.04 to 0.12% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.08 to 0.24% of Ti, 0.005 to 0.500% of Al, 0.01 to 0.06% of Nb, and 0.0005 to 0.0100% of N, a balance including Fe and impurities, wherein Vc90, defined by the following Formulae (i) and (ii), is 200 or more, a mass ratio of Ti content to C content is from 0.85 to 5.00, an areal ratio of ferrite is 80% or more, an average crystal grain size of ferrite crystal grains is 10 μm or less, and an average aspect ratio of ferrite crystal grains is 2.0 or less, in a metallographic microstructure of a central portion in a wall thickness direction of the base metal portion; log Vc90=2.94−0.75(βa−1) Formula (i);βa=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo Formula (ii).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.