PRODUCTION OF HOT-ROLLED STRIP AND HOT-ROLLED STRIP Russian patent published in 2014 - IPC C21D8/02 C21D1/02 C22C38/00 C22C38/58 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to production of hot-rolled 2-12 mm deep steel sheet from low-alloy steel with carbon content of 0.04-0.08 wt % and containing niobium and titanium. To get good mechanical properties, including bend ability, steel blank is subjected to austenitising at 1200-1350°C and pre-rolled. Then, it is rolled at rolling mill with temperature of 760-960°C at final pass at rolling moll. Then, sheet strip is subjected to direct quenching by single cooling at temperature gradient of 30-150°C/s to temperature of at least 300°C. Note here that direct quenching is carried out for 15 s after final pass. Steel strip has microstructure consisting of ferrite and/or bainite and/or martensite and/or residual austenite. Note here that rupture strength makes 650-800 MPa, elongation after rupture of at least 12%, elongation factor of 0.8-0.95. Note also that relationship between rupture strength in rolling direction and that in direction across rolling makes 6%.

EFFECT: good mechanical properties.

16 cl, 5 tbl, 7 dwg