METHOD OF PRODUCTION OF A SHEET STEEL Russian patent published in 2005 - IPC

FIELD: metallurgy, production of rolled steel.

SUBSTANCE: the invention is pertaining to the field of metallurgy, production of rolled steel, in particular, to methods of production of cold rolled steel sheets with the high drawing properties for a cold forming of details of cars bodies. The technical problem being solved by the invention consists in improvement of the quality of a cold rolled sheet steel. The method provides for hot rolling of continuously-cast low-carbon steel slabs, etching treatment, multirun cold rolling with total relative reduction of no less than 75 %, a recrystallization annealing in the following mode: a heating at an average speed of 70-80°C/h up to temperature of 490-510°C, a repeated heating at an average speed of 3-4 °C/h up to the intermediate temperatures of 540-560 °C/h and the final heating at an average speed of 50 - 55°C/h up to the annealing temperature of 700-720 °C, at which the steel rolls are kept for 12-18 h. Upon termination of keeping the rolls at the annealing temperature they are cooled at the rate of 19-21 °C/h up to the temperatures not exceeding 690 °C. At that the continuously cast low-carbon steel slabs have the following chemical composition (in mass %): 0.025-0.050 - carbon, 0.003-0.010 - silicon, 0.12-0.19 - manganese, 0.02-0.05 - aluminum, no more than 0,011 - nitrogen, the rest - iron and impurities.

EFFECT: the invention ensures improvement of the quality of a cold rolled sheet steel.

3 cl, 5 ex, 3 tbl