COATED STEEL SUBSTRATE Russian patent published in 2021 - IPC C23C26/00 C21D8/02 C22C38/58 

FIELD: coatings.

SUBSTANCE: present invention relates to a steel substrate with a coating containing nanographite flakes with a transverse size in the range between 1 and 60 mcm and a binder, as well as to a method for manufacturing said coated steel substrate and a method for manufacturing a hot-rolled steel product using said substrate. The steel substrate comprises the following components, wt.%: 0.31 ≤ C ≤ 1.2, 0.1 ≤ Si ≤ 1.7, 0.7 ≤ Mn ≤ 3.0, P ≤ 0.01, S ≤ 0.1, Cr ≤ 0.5, Ni ≤ 0.5, Mo ≤ 0.1 and optionally one or several elements selected from Nb ≤ 0.05, B ≤ 0.003, Ti ≤ 0.06, Cu ≤ 0.1, Co ≤ 0.1, N ≤ 0.01, V ≤ 0.05, iron and unavoidable impurities the rest. The thickness of the coating is in the range from 10 to 250 mcm. The binder constitutes sodium silicate, or the binder includes aluminium sulphate and an additive constituting aluminium oxide. The method for manufacturing a coated steel substrate includes the following consecutive stages: producing a steel substrate with the said steel composition, depositing the coating using an aqueous mixture containing 1 to 60 g/l of nanographite and 150 to 250 g/l of a binder to produce a coating, and optionally drying the coated steel substrate. During implementation of the method for manufacturing a hot-rolled steel product using the desсribed coated steel substrate, the coated steel substrate is reheated in a reheating furnace at a temperature in the range from 750 to 1,300°C, scale is removed from the reheated coated steel substrate, and the steel product with removed scale is hot-rolled.

EFFECT: decarburisation of steel is reduced during the processing in heating.

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