METHOD OF PRODUCING COLD-ROLLED PRODUCTS Russian patent published in 2025 - IPC C21D8/02 C21D9/46 B21B3/02 C22C38/40 C22C38/42 C22C38/44 C22C38/48 C22C38/50 C22C38/54 C22C38/60 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of cold-rolled products from hypoeutectoid alloyed steel used in automotive industry, machine building, which involve use of high-precision, high-strength cold-rolled products for production of parts with high elasticity limit. Proposed method comprises steel melting, casting, rough and finish hot rolling, etching, spheroidizing annealing, cold rolling, recrystallization annealing and temper rolling. Steel is melted with the following content of elements, wt.%: carbon 0.4–0.6, silicon 0.1–0.45, manganese 0.6–1.2, sulphur is not more than 0.010, phosphorus not more than 0.015, chrome 0.7–1.3, nickel not more than 0.4, copper not more than 0.4, nitrogen not more than 0.012, aluminium 0.01–0.08, boron not more than 0.005, niobium is not more than 0.15, vanadium 0.05–0.3, titanium not more than 0.10, molybdenum not more than 0.15, lead not more than 0.10, iron and unavoidable impurities – the rest. Rough hot rolling is completed at temperature of 1000–1150 °C, finishing hot rolling is completed at temperature of 900–1050 °C, strips are coiled at temperature of 600–750 °C, then hot-rolled stock is etched, spheroidizing annealing is performed at temperature of 670–760 °C, cold rolling is performed with relative reductions per pass of 1.5–35%, after which recrystallization annealing of coils is carried out at temperature of 650–730 °C and temper rolling is carried out with relative reduction of not more than 1.0%. The decarbonized layer for each rolled product surface is not more than 1% of the thickness, the fraction of granular pearlite is not less than 70%, and the granular pearlite grade is not more than 5 points.

EFFECT: obtaining high-strength cold-rolled stock with high mechanical properties and thickness tolerance of not more than +/-0.05 mm on the entire area of rolled stock.

4 cl, 3 tbl, 3 ex