METHOD OF PRODUCING CORROSION-RESISTANT PAINTED ROLLED STEEL WITH ZINC-ALUMINUM-MAGNESIUM COATING Russian patent published in 2020 - IPC C23C2/06 C23C2/26 C23C22/34 C23C22/78 C23C22/84 C23C28/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely, to continuous method of steel strip production. Method involves preparation of steel strip before coating, application of Zn-Al-Mg coating by hot immersion, degreasing and conversion of surface of Zn-Al-Mg coating, application of soil on one or two sides of steel strip, application of finishing enamel on one or two sides of steel strip. Concentrations of chemical elements in hot coating bath are, wt%: Al 1.0–1.4, Mg 1.0–1.4, Zn is the rest. Water solution of alkaline salt with pH=10–12 is used for degreasing and removal of oxide film from surface of Zn-Al-Mg coating. For application of conversion layer chromium-free compositions based on dihydrogen hexafluorotitanate or combination of hexafluorotitanate dihydrogen with hexafluorozirconium acid are used. Quality of conversion layer is evaluated by amount of precipitated titanium, which should be 3–12 mg/m². Temperature difference between curing of soil and finishing enamel is 0–5 °C, and the time of hardening of soil and finishing enamel is 0–10 s.

EFFECT: invention can be used at metallurgical enterprises when producing a steel strip with a coating having high corrosion resistance.

5 cl, 2 dwg, 1 tbl, 1 ex