METHOD FOR MANUFACTURE OF SHEET PRODUCTS FROM LOW-CARBON OR LOW-CARBON LOW-ALLOY STEEL (VERSIONS) Russian patent published in 2004 - IPC

FIELD: metallurgy, in particular, manufacture of hot-rolled sheets from low-carbon or low-carbon low-alloy steel for subsequent cold deformation by deep drawing, extrusion and other processes.

SUBSTANCE: method involves heating forged steel slab of 140x400 mm section to temperature of 1,150⁰C and rolling along slab axis with reduction extent of 60%, with finishing rolling temperature being 980⁰C; cutting resultant rolled slab into sheet bars; cooling sheet bars in air to temperature of 550⁰C; heating to temperature of up to 1,080⁰C and rolling transverse to basic slab rolling direction into 18-mm thick sheets with reduction extent of 68%, with finishing rolling temperature reaching 940⁰C and ratio of longitudinal deformation extent to transverse deformation extent being related by dependence of 0.5 ≤ γ ≤ 1.5 and equal to 0.88; subjecting hot rolled sheets cooled to room temperature to quenching process from temperature of 950⁰C by cooling in water with following high tempering in hood furnace at temperature of 680⁰C and holding for 10 hours; cooling metal charge in air to room temperature. According to first and second versions, rolling process is performed initially in longitudinal direction and finally in transverse direction or vice versa. According to third version, hot deformation direction is changed in the following sequences: hot rolling is performed in longitudinal direction and hot rolling of resultant rolled products - initially in transverse direction, then in longitudinal direction, with deformation extent values being related by dependence of 0.5 ≤ γ' ≤ 1.5, (2), where γ' is ratio of total slab and rolled product longitudinal and transverse deformation extent, or slab hot rolling process is initially performed in longitudinal direction, then in transverse direction, with deformation extent values related by dependence of 0.5 ≤ γ'' ≤ 1.5, where γ'' is ratio of rolled product longitudinal deformation extent to slab and rolled product transverse total deformation extent.

EFFECT: minimal anisotropy of mechanical properties and high plasticity of hot rolled sheets allowing articles to be produced by various processes.

12 cl, 1 tbl, 4 ex