BIMETALLIC ROLLED STEEL WITH THICKNESS OF 2-30 mm AND BIMETALLIC LONGITUDINAL SEAM OF MEDIUM OR SMALL DIAMETER MADE FROM IT Russian patent published in 2025 - IPC B32B15/01 B32B15/18 C22C38/58 C22C38/54 C22C38/50 C22C38/48 C22C38/46 C22C38/44 C22C38/42 C21D8/02 C21D8/10 B23K20/04 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of two-layer rolled steel with thickness of 2-30 mm, intended for production of longitudinal welded pipes of medium and small diameters (up to 426 mm). Bimetallic rolled stock consists of the main layer of carbon, low-alloyed or alloyed steel and cladding layer of corrosion-resistant steel. Steel of the main layer contains components at the following ratio, wt.%: carbon 0.04-0.25, silicon 0.05-1.0, manganese 0.2-2.0, sulphur is not more than 0.020, phosphorus not more than 0.025, chrome 0.01-2.5, nickel 0.001-0.5, copper 0.001-0.9, aluminium 0.01-0.10, molybdenum 0.001-1.00, vanadium is not more than 0.15, titanium not more than 0.15, niobium is not more than 0.15, nitrogen not more than 0.01, at least one element from the group: calcium not more than 0.005, boron not more than 0.005 and tungsten not more than 0.015, the rest is iron and unavoidable impurities. Steel of the main layer has impact strength at -60° not less than 39 J/cm², yield point not less than 200 MPa, ultimate strength not less than 330 MPa and relative elongation not less than 19%. Clad layer steel contains components at the following ratio, wt.%: carbon is not more than 0.15, silicon not more than 1.0, manganese not more than 1.0, sulphur is not more than 0.025, phosphorus not more than 0.025, chrome 10.0-15.0, nickel not more than 0.6, copper not more than 0.3, aluminium 0.01-0.15, molybdenum not more than 0.30, vanadium not more than 0.2, titanium not more than 0.15, niobium is not more than 0.15, nitrogen not more than 0.01, calcium not more than 0.005, boron not more than 0.005, the rest is iron and unavoidable impurities. Clad layer steel has hardness of 100-400HB. Adhesion strength of the main and cladding layers is not less than 350 MPa, and thickness of the cladding layer is 10-30 % of the total thickness of rolled stock.

EFFECT: rolled stock has high complex of mechanical properties and high corrosion resistance.

2 cl, 2 tbl, 1 ex