FLAT STEEL FROM CONSTRUCTION COLD-ROLLED STEEL MANUFACTURING METHOD (OPTIONS) Russian patent published in 2019 - IPC C21D8/02 B21B1/26 C22C38/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, in particular to the sheet mill products production from structural steels of northern execution. To improve the cold resistance and crack resistance while maintaining a sufficient level of strength and plastic properties in the mill products melting the steel containing, wt.%: carbon 0.09-0.13, manganese 1.40–1.60, silicon 0.50–0.70, aluminum 0.025–0.090, chromium 0.03–0.10, nickel 0.02–0.10, copper 0.03–0.10, molybdenum 0.002–0.050, titanium 0.004–0.025, niobium 0.001–0.01, vanadium 0.003–0.010, nitrogen 0.001–0.008, sulfur 0.001–0.005, phosphorus is 0.003–0.016, calcium is 0.0001–0.01, iron is the rest, at that, by the method first embodiment, preliminary deformation with regulated reductions is carried out at a temperature of 950–1,100 °C, and the final deformation is carried out at a temperature of 880–760 °C, then sheet mill products are slowly cooled in the stack and in air to ambient temperature. According to the method second embodiment, after the final deformation completion, the sheet mill products accelerated cooling is carried out at a rate of 5–20 °C/s to a temperature of 700–600 °C and then the sheet mill products are cooled in air.

EFFECT: increase in the cold resistance and crack resistance while maintaining a sufficient level of strength and plastic properties.

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