METHOD OF METAL SHEET PROCESSING TO REDUCE ITS BROWNING OR TARNISHING DURING STORAGE AND METAL SHEET PROCESSED BY THIS METHOD Russian patent published in 2017 - IPC C23C2/02 C23C2/06 C23C2/26 C23C22/60 C23C22/68 C25D11/34 C23C28/00 

FIELD: metallurgy.

SUBSTANCE: metal sheet comprises a steel substrate coated on at least one of its sides with a coating containing 0.1-20 wt % magnesium, optionally 0.1-20 wt % aluminium, the rest is zinc, possible impurities due to the process and, if necessary, one or more additional elements selected from Si, Sb, Pb, Ti, Ca, Mn, Sn, La, Ce, Cr, Ni, Zr and Bi. The weight content of each additional element is less than 0.3%. The coating also comprises a layer based on zinc hydroxychloride with the weight of the chlorine layer comprising at least 1 mg/m². The layer contains no hydrozincite, mixed hydroxy carbonates of zinc, aluminium, water-soluble sodium or potassium compounds.

EFFECT: creating coatings on steel substrate that provide protection against browning and tarnishing which remain effective even in the absence of temporary protective lubricant.

16 cl, 3 dwg