METHOD FOR PRODUCING COATED STEEL PART FOR A CAR AND COATED STEEL PART Russian patent published in 2023 - IPC C21D8/04 B32B15/00 C23C2/26 B82Y30/00 

FIELD: steel production.

SUBSTANCE: group of inventions is related to a method for producing a coated steel part and to a steel part obtained by this method. The method includes the following steps: A. Providing steel sheet for heat treatment; B. adaptive rolling of the steel sheet in the rolling direction with a reduction of 1-50% to obtain a steel sheet of variable thickness; C. cutting a rolled steel sheet to obtain a rolled billet to size; D. applying a hydrogen absorption pre-coating steel sheet, 10-550 nm thick, containing at least one element selected from: nickel, chromium, magnesium, aluminium and yttrium, to the workpiece; E. heat treatment of the cut-to-size rolled billet at a temperature of 800-970°C exposed for 1-12 minutes to obtain a fully austenitic steel microstructure; F. moving the cut-to-size rolled stock into the mould; G. hot forming a custom-made rolled billet at a temperature of 600-830°C to obtain a part of variable thickness; H. cooling the workpiece of variable thickness obtained in step G) to obtain a martensitic steel microstructure. The coated steel part comprises a steel sheet of variable thickness, a pre-coating preventing the absorption of hydrogen by the steel sheet of the same thickness, diffusion-fused to the steel sheet, and coated with an oxide layer containing iron oxides from the steel sheet.

EFFECT: creating a method that prevents the absorption of hydrogen in a specially made-to-size rolled billet, as well as creating a part with suitable resistance to delayed fracture, which can be obtained by the specified method of hardening under pressure, including hot forming.

10 cl, 1 tbl, 1 ex