PROCEDURE FOR PRODUCTION OF LOW CARBON COLD ROLLED STEEL FOR PRESS FORMING AND SUCCESSIVE ENAMELLING Russian patent published in 2011 - IPC C21D8/04 C21D9/48 C22C38/16 

FIELD: metallurgy.

SUBSTANCE: there is melted steel containing wt %: carbon - 0.02-0.04, manganese - 0.1-0.2, silicon as high, as 0.02, sulphur as high, as 0.012, phosphorus as high, as 0.015, chromium as high, as 0.03, nickel as high, as 0.06, copper as high, as 0.06, nitrogen as high, as 0.006, aluminium 0.03-0.06, titanium 0.01-0.03, iron and unavoidable impurities - the rest. Steel is teemed, hot rolled for semi-finish rolled product to thickness below 2.5 mm at temperature (Ac₁+110)÷(Ac₃-20)°C, and for semi-finished rolled product of thickness over 2.5 mm at temperature (Ac₁+80)÷(Ac₃-50)°C. Winding of semi-finish rolled product of thickness below 2.5 mm is carried out at temperature Ac₁÷(0÷30)°C, while semi-finished rolled product of thickness over 2.5 mm is wound at temperature Ac₁-(10÷30)°C. Further, scale is etched, and there is performed cold rolling with degree of deformation 53-75 %. Product is annealed with heating to intermediate temperature of 580°C, and conditioned at this temperature during time τ=0÷χ, whereupon heated to temperature t=470+110·τ/χ during time τ=χ÷2χ and conditioned at this temperature during time τ=2χ÷7χ, where χ=0.1m+b/350, where m - is weight of coil, t, b is width of band, mm, τ is time, hour. Also, total duration of annealing is 36-64 hours. Temper rolling is performed with degree of deformation 0.9±0.1%.

EFFECT: facilitation of required complex of mechanical properties of band for press-forming and elimination of tendency of enamelled item to defect like fish scale.

2 ex, 2 dwg