METHOD OF MAKING STEEL STRIP (VERSIONS) Russian patent published in 2013 - IPC C22C38/42 C21D8/02 C21D9/46 

FIELD: metallurgy.

SUBSTANCE: proposed method comprises steel smelting, continuous casting of slabs to be heated, hot rolled, and water cooled; strip reeling, etching, cold rolling, recrystallisation annealing, application of zinc coating and/or pinch rolling. Smelt steel contains following substances, in wt %: carbon 0.001 - 0.015, silicon 0.001 - 0.50, manganese 0.05 -1.0, phosphorus not over 0.12, sulfur not over 0.025, chromium not over 0.30, nickel not over 0.30, copper not over 0.19, aluminium not over 0.02 - 0.15, nitrogen not over 0.010, iron and unavoidable impurities making the rest, including titanium and niobium making the rest. Note here that [Mn]/[S] ratio equals ≥ 4.8 while total content of titanium and niobium does not exceed 0.012 wt %. Slabs are heated at 1060°C to 1200°C. Hot rolling is terminated at 800-930°C. Strip reeling is performed at 550 to 730°C while cold rolling is performed to total reduction of 40-95%. Recrystallisation annealing is carried out in bell-type furnace at 600 - 750°C with holding for 6-35 hours or, in applying zinc coating in pusher furnace, at 750 - 900°C.

EFFECT: higher strength, better forming properties, lower costs.

4 cl, 4 tbl, 1 ex