METHOD OF PRODUCTION OF HIGHER-STRENGTH HOT-ROLLED STOCK Russian patent published in 2015 - IPC C21D8/02 B21B1/26 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: method involves making of steel containing the following components, wt %: carbon 0.03-0.12, silicon 0.10-0.50, manganese 1.5-2.0, sulphur max. 0.008, phosphorus max. 0.015, chrome 0.01-0.30, nickel 0.01-0.30, copper 0.01-0.30, aluminium 0.01-0.06, niobium 0.001-0.10, nitrogen 0.002-0.010, vanadium 0.001-0.10, titanium 0.001-0.10, molybdenum 0.005-0.30, calcium 0.0003-0.005, boron 0.0001-0.005, iron and inevitable admixtures - rest, including stannum, lead, zinc - each max. 0.010, hydrogen max. 0.001. Hot rolling in clean group of cages is performed at max. 950°C with degree of rerolling at least five rated thicknesses of finished rolled products. At that end of finished rolling is specified within range 750-860°C. Strip is wound at max. 480°C. At that mode of accelerated cooling is specified based on the CCT diagrams of disintegration of the overcooled austenite to ensure the beinite-martensite-ferrite structure with share of the beinit-martensite phase at least 90%.

EFFECT: production of hot-rolled products with required strength class and guaranteed level of impact energy and relative elongation.

3 cl, 3 tbl, 1 dwg