HIGH-STRENGTH STEEL STRIP AND METHOD FOR PRODUCTION THEREOF Russian patent published in 2020 - IPC C22C38/14 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to steel strip used for production of structural elements used in production of mining and port equipment, as well as in engineering machine building. Steel is melted in the form of a slab having the following chemical composition, wt. %: C 0.070–0.115, Si 0.20–0.50, Mn 2.00–2.20, Cr ≤ 0.35, Mo 0.10–0.40, Nb 0.03–0.06, V 0.03–0.06, Ti 0.002–0.04, Al 0.01–0.08, B 0.0006–0.0020, N ≤ 0.0060, O ≤ 0.0040, Ca ≤ 0.0045, Fe and non-eliminated impurities are the rest. Slab is heated to temperature of 1040–1250 °C and rolling is carried out in two steps to produce a strip, wherein multi-pass rolling is performed at the first and second steps. At first rolling step, rolling start temperature is 1010–1240 °C, and the degree of deformation at each pass is 8–30 %, and at the second rolling step, the rolling start temperature is 750–870 °C, rolling end temperature is 740–850 °C, and degree of deformation at each pass is 5–30 %. Rolled steel strip is first cooled by water cooling at cooling rate of 15–50 °C/s to temperature ≤ 450 °C, and then cooled by air cooling to room temperature. Release is performed at temperature of 450–650 °C, and then steel strip is cooled by means of air cooling.

EFFECT: high strength, impact viscosity at low temperatures and good weldability.

6 cl, 1 dwg, 3 tbl