PRODUCTION OF COLD-ROLLED STEEL SHEET Russian patent published in 2015 - IPC C21D8/04 C21D9/46 C22C38/04 

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Steel slab is heat-rolled from steel including in wt %: C - over 0.020 and less than 0.30, Si - over 0.10 and 3.00 or less, and Mn - over 1.00 and 3.50 or less. This is done so that reduction degree in rolls in a pass makes over 15% while rolling is terminated at temperature of Ar₃ range or higher. Thereafter, hot-rolled stock is cooled to 780°C or less and coiled at over 400°C or under 400°C. Hot-rolled steel sheet is annealed nu heating to 300°C or higher. Cold-rolling is performed so that obtained hot-rolled steel sheet or hot-rolled annealed steel sheet is converted into cold-rolled steel sheet. Annealing of cold-rolled steel sheet is performed by heating and holding at Ac₃ - 40°C or higher. Then, it is cooled to 500°C or lower and 300°C or higher and held thereat for 30 seconds or more.

EFFECT: high-strength cold-rolled steel sheet, good ductility and deformability, nice folding.

25 cl, 2 dwg, 12 tbl, 4 ex