PRE-COATED STEEL SHEET WITH ADDITIONAL COATING TO INCREASE MECHANICAL STRENGTH OF WELD METAL ZONE OF WELDED STEEL PART MADE FROM SAID PRE-COATED SHEET Russian patent published in 2023 - IPC C23C28/02 B23K26/322 C23C4/06 C23C4/12 C23C2/04 C23C2/36 

FIELD: steel manufacturing.

SUBSTANCE: group of inventions is related to a method for manufacturing a pre-coated steel sheet for manufacturing a welded steel part and a method for manufacturing a welded steel part from pre-coated steel sheets. The steel substrate in form of a steel sheet is provided with an aluminium-based or zinc-based pre-coating which is in contact with the surface of said steel substrate. On top of said coating, an additional nickel-based, or carbon-based, or nickel-and-carbon based coating is applied to at least the edge to be welded on at least one of the opposite surfaces of the pre-coated steel sheet. Said additional coating has an evaporation temperature higher than said pre-coating. By increasing the vapor pressure between said pre-coating and additional coating during laser butt welding to a critical pressure, the pre-coating is removed from the weld.

EFFECT: pre-coated steel sheet is provided that enhances the mechanical strength of the weld metal zone of welded steel part made from said sheet.

2 cl, 10 dwg, 2 tbl, 2 ex