METHOD OF PRODUCING COLD-ROLLED STEEL FOR DEEP-DRAWING Russian patent published in 2008 - IPC C21D8/04 C21D9/48 C22C38/14 

FIELD: metallurgy.

SUBSTANCE: invention concerns the ferrous metallurgy field. Particularly it concerns manufacturing of strip for producing odd-shaped items, mainly car parts including protective coating. While drying of lacquer coating on completed part so-called BH-effect (bake-hardening effect), it is implemented melting of steel contained mass%: carbon - 0.001-0.008, silicon - 0.002-0.025, manganese - 0.05-0.30, phosphorus - 0.005-0.060, sulphur - 0.003-0.012, aluminium - 0.010-0.070, nitrogen - 0.002-0.006, titanium - any more than 3.43N+0.005, where N - nitrogen content, niobium - any more than 7.736C - 0.0035, where C - carbon content, iron and inevitable admixture are the rest, teeming, hot rolling, winding of strips in rolls, cold rolling, recrystallisation annealing at temperature T_annealing no less 750°C, which value is selected at dependence: |T_annealing|≥875-62500(|C|-|Nb| /7.736), |C|, |Nb| - absolute value carbon and niobium content, conformably, refrigeration before 450-500°C at a rate of V °C/c, which absolute value is defined from ratio 0.04T_annealing.-23 ≤ |V| ≤ 20, where T_annealing. - annealing temperature, °C, 0.04 - empirical coefficient, 1/°C, galvanised coating and pinch rolling.

EFFECT: support of strip high blanking, heightened level of strength characteristics, which is achieved as a result of strengthening.

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