METHOD FOR PRODUCING HIGH-STRENGTH HOT-ROLLED STEEL Russian patent published in 2023 - IPC C21D8/04 C21D9/46 C22C38/42 C22C38/44 C22C38/46 C22C38/48 C22C38/54 C22C38/58 

FIELD: metallurgy.

SUBSTANCE: invention relates to a method for producing high-strength hot-rolled products from low-alloy steel intended for the manufacture of car parts by stamping. The method for producing high-strength hot-rolled steel includes obtaining a steel billet, its austenitization, rolling, and coiling. A billet is obtained from steel containing, wt.%: carbon 0.03-0.10, silicon 0.05-0.35, manganese 1.0-1.70, sulphur not more than 0.010, phosphorus not more than 0.015, chromium not more than 0.5, nickel no more than 0.5, copper no more than 0.50, aluminium 0.02-0.08, titanium 0.01-0.2, molybdenum 0.01-0.30, vanadium no more than 0 .15, niobium no more than 0.15, nitrogen no more than 0.010, boron no more than 0.002, if necessary calcium no more than 0.005, iron and inevitable impurities are the rest. Austenization of the billet is carried out to a temperature of 1150-1300°C, rough rolling begins at a temperature of 1100-1220°C, finishing rolling begins at a temperature of 950-1150°C, finished at a temperature of 800-900°C, after this the rolled product is wound into a roll at a temperature of 550-700°C, whereas the rolled product has a microstructure consisting of ferrite in an amount of at least 95% and is characterized by a non-metallic inclusion score of no more than 2.5 on average and no more than 3 on the maximum value.

EFFECT: rolled products are characterized by high cold resistance, fatigue endurance and high ability to expand holes, as well as manufacturability when profiling and forming parts.

2 cl, 3 tbl