METHOD FOR PROCESSING SHEET METAL AND SHEET METAL SUBJECTED TO PROCESSING USING SAID METHOD Russian patent published in 2021 - IPC C23C2/06 C23C2/26 C23C22/53 C23C22/78 C23C28/00 

FIELD: processing of metals.

SUBSTANCE: invention relates to production of a coated steel strip. The method includes stages wherein a strip of steel is provided with a metal coating based on zinc or alloys thereof applied to at least one of the front surfaces whereof, an aqueous solution for surface treatment, containing no less than 0.01 mol/l of zinc sulphate is applied to the metal coating by means of simple contact in order to produce a wet film, and then said aqueous solution is dried in a dryer at an air drying temperature greater than 170°C. The time between application of the aqueous solution to the metal coating and exit from the dryer is less than 4 seconds. The velocity of the strip, the thickness of the wet film, the initial temperature of the strip, and the air flow rate are adapted to produce a layer based on zinc sulphate on the metal coating, containing no free water molecules and free hydroxyl groups, wherein the surface density of sulphur in the layer based on zinc sulphate is greater than or equal to 0.5 mg/m².

EFFECT: production of a layer based on zinc sulphate on the processed surface, characterised by good adhesion relative to epoxy adhesives, while maintaining other properties of the initial layer based on zinc hydroxysulphate.

5 cl, 9 dwg, 5 ex