METHOD OF PRODUCING COLD-ROLLED CONTINUOUSLY ANNEALED FLAT PRODUCTS FROM IF-STEEL Russian patent published in 2020 - IPC C21D8/04 C22C38/14 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of cold-rolled stock from IF-steels, which is used in automotive industry. To ensure level of properties corresponding to steels of grades DC05, DC06 and DC07 to EN 10130, i.e. creation of cassette technology, while maintaining high plasticity and moldability, steel is melted, containing, wt. %: C 0.002–0.006; Si 0.005–0.020; Mn – 0.08–0.13; Al – 0.03–0.06; Ti – 0.03–0.08; Fe and unavoidable impurities – the rest, casting, hot rolling with rolling end temperature of 900–930 °C, etching, strips coiling, cold rolling, recrystallization annealing in continuous annealing unit, wherein recrystallization annealing is performed by heating to 830–840 °C for rolled stock with minimum value of relative elongation of 39–40 % and up to 850–860 °C for rolled metal with minimum value of relative elongation of 42–44 %, holding and cooling to the overage temperature, wherein the overage start temperature is assigned in accordance with the relationship To.i.≤[920-12.5xδrq_.], where To.i. is overage initiation temperature, °C, δrq. required minimum value of relative elongation, %; 920 and 12.5 are empirical coefficients and are rolled.

EFFECT: maintaining high plasticity and levelling.

1 cl, 3 tbl