Electric resistance welded steel pipe for torsion beam
US11739866B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 2018 |
| Grant date | Aug 29, 2023 |
| Priority date | — |
| Expiry date | May 27, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D9/46
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An electric resistance welded steel pipe for a torsion beam, in which a chemical composition of a base metal portion contains, in terms of % by mass, 0.05 to 0.30% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.010 to 0.200% of Ti, 0.005 to 0.500% of Al, 0.010 to 0.040% of Nb, and 0.0005 to 0.0050 % of B, the balance containing Fe and impurities, wherein: Vc90, defined by the following Formula (i), is from 2 to 150, a mass ratio Ti/N is 3.4 or more, a microstructure of a wall thickness central portion in an L cross section at a base metal 1800 position is a tempered martensite, an average aspect ratio of prior γ grains in the tempered martensite is 2.0 or less, and a tensile strength in the pipe axis direction is from 750 to 980 MPa: log Vc90=2.94−0.75βa Formula (i)βa=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+2Mo Formula (ii).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.