METHOD FOR PRODUCING HOT-PLATED PRODUCT BY HOT ROLLING, DIRECT COLD ROLLING WITHOUT PICKLING, AND REDUCTION ANNEALING Russian patent published in 2019 - IPC C23C2/00 C23C2/06 C21D8/02 C23F17/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to production of hot-plated steel sheet. Method comprises hot rolling at hot rolling mill, cold rolling without etching at cold rolling mill, low annealing in reducing furnace in reducing gas medium, hot dipping coating application. At hot rolling step after dephosphorisation, hot-rolled steel sheet is successively subjected to rough rolling at coarse rolling mill, finishing rolling at finishing mill, cooling by means of cooling device, and winding by coiler, wherein the thickness of the layer of iron oxides on the surface of the sheet is reduced by reducing the temperature of the outlet and increasing the rolling speed, besides, controlling the cooling rate after rolling and the winding temperature. Cold-rolling step optimizes parameters of low-temperature rolling process and uses lubricating-cooling liquid. At low annealing step reducing gas is introduced into reduction furnace, temperature and recovery time are controlled, and reduction temperature is 500–1000 °C, recovery time is 60–300 sec, and reducing gas is a mixture of H₂ or CO with an inert gas, in which concentration of H₂ or CO not lower than 3 %, wherein the layer of iron oxides is partially reduced to ferrous metal, after which the steel sheet is cooled to the temperature of immersion of the steel sheet into the bath with molten metal at the stage of coating application.

EFFECT: due to exclusion of etching process invention enables to quickly, highly efficient and environmentally safe to produce hot-plated steel sheet, wherein it is possible to control structure of layer of iron oxides on surface of hot-rolled steel sheet and increase of adhesion strength of layer of iron oxides at reduction of its thickness.

15 cl, 6 dwg, 1 tbl, 5 ex