METHOD OF PRODUCING A STEEL STRIP WITH IMPROVED ADHESION OF HOT-DIPPED METAL COATINGS Russian patent published in 2022 - IPC C23C2/02 C23C2/06 C23C2/12 C21D9/46 C25D11/02 C22C38/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to production of steel strip with improved adhesion of hot-dipped metal coatings, containing, in addition to iron as the main component and unavoidable impurities, one or more of the following oxygen-affine elements, wt. %: Al more than 0.02, Cr more than 0.1, Mn more than 1.3 or Si more than 0.1. In the method, the surface of the steel strip is cleaned, subjected to oxidative treatment at temperature below 200 °C by anodic oxidation to form an oxide layer on the surface of the steel strip with a minimum thickness of at least 5 nm to maximum of 500 nm, is subjected to annealing, followed by application of a coating by hot dipping. Anodic oxidation is carried out at current densities from 50 to 400 A/dm² and in 20–60 % NaOH solution or KOH solution at an electrolyte temperature of at least 45 °C to a temperature of maximum 3 °C below the boiling point of the electrolyte. On the surface of the steel strip, when oxides are formed with iron of the steel strip, an oxide layer is formed, which contains iron oxide and which is subjected to reduction treatment during annealing in a reducing atmosphere to obtain a surface consisting essentially of metallic iron.

EFFECT: disclosed is a method of making a steel strip with improved adhesion of hot-dipped metal coatings.

11 cl, 3 dwg