High-strength welded steel pipe for airbag inflator and method for manufacturing the same
US10301703B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 19, 2015 |
| Grant date | May 28, 2019 |
| Priority date | — |
| Expiry date | Apr 24, 2036 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60R2021/2612
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed is a high-strength welded steel pipe for airbag inflators that has high toughness and workability. A base material portion of the steel pipe has a composition containing, in mass %, C: 0.02 to 0.08%, Si: 0.001 to 1.0%, Mn: 0.1 to 2.0%, P: 0.1% or less, Al: 0.01 to 0.1%, N: 0.01% or less, Ti: 0.01 to 0.20%, and V: 0.01 to 0.50%, with the balance being Fe and incidental impurities. The base material portion has a structure that includes a ferrite phase having an average grain size of 10 μm or less at an area fraction of 90% or more and a Ti, V-based carbide having an average grain size of 10 nm or less and dispersed in the ferrite phase. The welded steel pipe has a high tensile strength TS of 780 MPa or more and a strength-elongation balance TS×El of 15,000 MPa % or more. The difference ΔHV in Vickers hardness between the base material portion and the welded portion is 60 points or less. In a softened portion having Vickers hardness different from the Vickers hardness of the base material portion by at least 30 points, a softened width Ws in a circumferential direction is 0.05 mm or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.