Method for the manufacture of a hardened part which does not have LME issues
US11162153B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 2016 |
| Grant date | Nov 2, 2021 |
| Priority date | — |
| Expiry date | Feb 28, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2211/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention provides a method for the manufacture of a hardened part. The method includes the provision of a steel sheet pre-coated with a metallic coating including from 2.0 to 24.0% by weight of zinc, from 1.1 to 7.0% by weight of silicon, optionally from 1.1 to 8.0% by weight of magnesium when the amount of silicon is between 1.1 and 4.0%, 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, wherein the ratio Al/Zn is above 2.9. The method further includes the cutting of the coated steel sheet to obtain a blank, the thermal treatment of the blank at a temperature between 840 and 950° C. to obtain a fully austenitic microstructure in the steel, the transfer of the blank into a press tool, the hot-forming of the blank to obtain a part, the cooling of the part in order to obtain a microstructure in steel being martensitic or martensitic-bainitic 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.