METHOD OF PRODUCTION OF THE WIDE HOT-ROLLED STEEL STRIPS Russian patent published in 2006 - IPC C21D8/02 C21D9/46 

FIELD: ferrous metallurgy; methods of production of the wide hot-rolled steel strips.

SUBSTANCE: the invention is pertaining to the field of ferrous metallurgy, in particular, to the hot-rolling production of the wide hot-rolled steel strips and may be used at production of the wide hot-rolled strips predominantly made out of the medium-carbon steel grades of the depth less than 5.5 mm. The technical result of the invention is assurance in the medium grades carbon steel hot-rolled rolling of the isotropic evenly distributed structure of pearlite with dispersivity of no more than 4-th grade by the strict regulation of the temperature conditions of the final part of the rolling and reeling of the hot strips into the rolls depending on their final depth. The technical result is reached due to the fact, that the slab with a carbon content of 0.42 - 0.55 % is heated up, rolled in the rough and finishing continuous trains with the temperature of the end of the rolling of 700-800°C, and gain the strip with the depth of no more than 5.5 mm, cool it by water from above and below using the sections of the shower device mounted on the collecting roller table and winding it into a roll at the temperature of 500 - 600°C. The temperature of the final part of the rolling and the reeling is set depending on the final depth of the straps. At that the temperature of the final part of the rolling set: - for strips depth of 5.5 - 4.5 mm inclusively - no more than 780°C; - for the strips of the depth of less than 4.5 - 3.5 mm inclusively - no more than 800°C; - for the strips of the depth less than 3.5-30 mm inclusively - no more than 810°C, for the strips of the depth less than 3.0 - 2.5 mm inclusively - no more than 820°C, and for strips of the depth less than 2.5 mm - no more than 830°C. At that the temperature of the reeling is set depending on the final depth: - for the strips with the depth of 5.5 - 4.5 mm inclusively it is no more than 560°C; - for the strips with the depth of less than 4.5 - 3.5 mm inclusively - no more than 590°C; - for the strips of the depth of less than 3.5 - 3.0 mm inclusively - no more than 600°C; - for the strips with the depth of less than 3.0 - 2.5 mm inclusively - no more than 610°C and for the strips of the depth less than 2.5 mms - no more than 620°C.

EFFECT: the invention ensures achievement in the medium grades carbon steel hot-rolled rolling of the isotropic evenly distributed structure of pearlite with dispersivity of no more than 4-th grade by the strict regulation of the temperature conditions of the final part of the rolling and reeling of the hot strips into the rolls depending on their final depth.

1 tbl, 1 ex