Phosphatable part starting from a steel sheet coated with a metallic coating based on aluminum
US12104255B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2022 |
| Grant date | Oct 1, 2024 |
| Priority date | — |
| Expiry date | Oct 17, 2042 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A hardened part coated with a phosphatable coating is provided. The part is made by a method that includes providing a steel sheet pre-coated with a metallic coating including from 4.0 to 20.0% by weight of zinc, from 1.0 to 3.5% by weight of silicon, optionally from 1.0 to 4.0% by weight of magnesium, and optionally additional elements chosen from Pb, Ni, Zr, or Hf, the content by weight of each additional element being less than 0.3% by weight, the balance being aluminum and unavoidable impurities and residuals elements. The steel sheet is cut to obtain a blank, the blank is thermally treated at a temperature between 840 and 950° C. to obtain a fully austenitic microstructure in the steel, the blank is transferred into a press tool and hot-formed to obtain a part. The part is cooled to obtain a martensitic or martensitic-bainitic microstructure or made of at least 75% of equiaxed ferrite, from 5 to 20% of martensite and bainite in amount less than or equal to 10%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.