Patent ID: 9611517
Date: 2017-04-04
CPC Classifications: B32B,C21D,C22C,C23C,Y10T

Claim:
1. A process for manufacturing a coated steel part, the process comprising: hot rolling or cold rolling a steel sheet, comprising, Fe and, by weight: to obtain a rolled sheet; precoating the rolled sheet with a precoating, which is an alloy comprising zinc or aluminum, to obtain a coated sheet; cutting the coated sheet to obtain a blank; heating the blank to a temperature Tc in a furnace to form, by alloying the steel and the precoating, an alloyed layer on a surface of the blank, wherein the alloying is carried out over an entire thickness of the alloyed layer, and the steel comprises an entirely austenitic structure after heating; removing the blank from the furnace, and, optionally, hot deforming the blank, to obtain a part precursor; and cooling the part precursor within a tool under conditions to obtain intended mechanical properties in a coated steel part, wherein the steel of the steel part has a microstructure comprising at least 75% equiaxed ferrite, martensite in an amount not less than 5% but not exceeding 20%, and bainite in an amount not exceeding 10%, expressed as surface fractions.