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US 12,716,107 B2Granted
Press hardening method
AssigneeArcelorMittal
InventorsCédric Georges, Florin Duminica, Thierry Sturel, Pascal Drillet
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Abstract
A carbon steel sheet coated with a barrier pre-coating containing nickel and chromium in a weight ratio between 1.5 and 9, and a press hardening method for providing the carbon steel sheet coated with a barrier pre-coating comprising nickel and chromium are described.
Claims9
A press hardening method comprising the following steps:
- a) provision of a carbon steel sheet coated with a barrier pre-coating comprising nickel and chromium, wherein the weight ratio Ni/Cr is between 1.5 and 9,
- b) cutting of the coated carbon steel sheet to obtain a blank,
- c) thermal treatment of the blank,
- d) transfer of the thermally treated blank into a press tool,
- e) hot-forming of the transferred thermally treated blank to obtain a part,
- f) cooling of the part obtained at step e) in order to obtain a microstructure in steel that is 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%, wherein the carbon steel sheet of step a) is directly topped by an anticorrosion pre-coating layer, this anticorrosion pre-coating layer being directly topped by the barrier pre-coating.
3 more elements
Dependencies are inferred from the claim text.