METHOD FOR PRODUCING HIGH-STRENGTH THICK-STEEL STEEL ROLLING ON A REVERSING MILL Russian patent published in 2021 - IPC C21D8/02 C21D9/46 C21D1/18 C22C38/48 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, and in particular to a method for producing high-strength thick-plate rolled steel on a reversing mill. The invention can be used to produce low-alloy pipe steels. The above method includes smelting a continuously cast steel billet, heating and holding it at austenitizing temperature, rough rolling, cooling in air and subsequent finishing rolling to a given sheet thickness and straightening. A continuously cast billet is made of steel with the following ratio of elements, wt%: C≤0.08, Mn≤1.0, Si≤0.3, Al≤0.03, (Cu+Cr+Ni)=1.2- 2.1, Nb≤0.04, Mo≤0.04, V≤0.04, S≤0.002, P≤0.01, iron - the rest. Rough rolling is carried out with a deformation end temperature of 930-955°C, with a value of partial relative reductions of 5-18%, ensuring the thickness of the intermediate rolling stock in the range of 3.0-6.5 of thicknesses of the finished sheet. Finishing rolling to the final sheet thickness is carried out at a value of partial relative reductions of at least 9%. The last pass is carried out with a partial relative reduction necessary to obtain a given sheet thickness at a deformation end temperature of 820-860°C. After the rolled sheet has cooled to room temperature, it is heated for quenching to a temperature of 930-960 °C with a specific heating time of 2.0-2.8 min/mm of sheet thickness and subsequent quenching in a roller quenching machine with accelerated cooling to a temperature not exceeding 100 °С with a total cooling water flow rate of 600-1000 m³/h.

EFFECT: invention provides production of sheet metal of K52-K60 strength categories with increased corrosion resistance and cold resistance.

1 cl