ASSEMBLY UNIT CONTAINING AT LEAST TWO METAL SUBSTRATES Russian patent published in 2022 - IPC B23K11/11 B23K11/16 

FIELD: metallurgy.

SUBSTANCE: group of inventions relates to the manufacture of an assembly unit containing at least two metal sheets, and can be used, in particular, in the manufacture of automobiles. One of the sheets is a hardened steel sheet having an alloyed coating based on aluminium, with a layer of natural oxide containing ZnO and optionally MgO. Sheets are connected by contact spot welding. At least one current pulse (Cp) is passed through the sheets so that at least part of the oxide layer and/or alloyed coating is broken and removed. Immediately after that, welding is performed, characterized by welding current (Cw), which differs from current Cp and is limited by its minimum and maximum values with control limit equal to or greater than 1 kA. Duration of pulsation is less than duration of welding.

EFFECT: selection of parameters of the method provides welding without splashes with production of a welded spot seam having minimum allowable diameter, which guarantees quality and strength of a seam.

23 cl, 5 dwg, 1 tbl, 1 ex