Spot welding method of high-strength steel sheets excellent in joint strength
US10040145B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 2012 |
| Grant date | Aug 7, 2018 |
| Priority date | — |
| Expiry date | Sep 23, 2033 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K2103/04
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
When two high-strength steel sheets (1A, 1B) whose sheet thickness ratio={the sum of sheet thicknesses of the steel sheets}/{the sheet thickness of the thinner steel sheet (when they have the same thickness, the sheet thickness per one sheet)} is within a range of not less than 2 nor more than 5 and which both have tensile strength of not less than 780 MPa nor more than 1850 MPa are stacked to be subjected to resistance spot welding, a first welding step being pre-welding with a pressurizing force P1 kN and a welding current I1 kA and a second welding step being main welding with a pressurizing force P2 kN and a welding current I2 kA are performed, the pressurizing forces P1, P2 are set to a fixed pressurizing force P=P1=P2 all through the first welding step and the second welding step and are set within a range expressed by {0.5≤P≤3.0t(1/3)}, where t mm is an average sheet thickness of the steel sheets (1A, 1B), the welding current I1 is set within a range of not less than 30% nor more than 90% of the welding current I2, and the second welding step is started within 0.1 s after the first welding step is finished.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.