DOUBLE-LAYER HOT ROLLED SHEETS MAKING METHOD Russian patent published in 2005 - IPC

FIELD: metallurgy, namely production of double-layer sheets having basic layer of carbon, low alloy or alloy steel and cladding layer of corrosion resistant steel and designed for using in oil production, chemical and other industry branches where combination of corrosion resistance and high mechanical properties is needed.

SUBSTANCE: method of producing double-layer hot rolled sheets with cladding layer of corrosion resistant steel comprises steps of producing double-layer blanks by electroslag surfacing; rolling double-layer blanks to sheets. According to invention electroslag surfacing is realized with use of consumable electrodes of corrosion resistant steel containing, mass %: carbon, 0.02 - 0.12; silicon, 0.2 - 0.8; manganese, 1.3 - 2.5; phosphorus,, no more than 0.040; sulfur, no more than 0.015; chrome, 20 -23; nickel, 10 -14; niobium, no more than 1.5; nitrogen, no more than 0.04; iron and inevitable impurities, the balance. Minimally admissible content of niobium is determined according to carbon content with use of expression: (Nb) = 10(C) where (Nb) - content of niobium in steel of cladding layer, mass %; (C) - carbon content in steel of cladding layer, mass %. Double-layer blanks are stepwise heated for rolling: at first they are heated in furnace at temperature 650 -1000°C for total time period of presence of blanks in furnace (including heating and soaking)τ₁ min ≥ 0.1 h where h - thickness of double-layer blank, mm. Then blanks are heated till temperature 1160 -1280°C together with furnace for total time period of heating and soaking τ₂ min ≥ 0.9 h where h - thickness of double-layer blank, mm. At rolling process rolled pieces are slightly cooled from 1070 ±20°C to 1030±5°C without deformation of metal in such temperature range. Rolling process is terminated at temperature no less than 960ºC.

EFFECT: enhanced strength and integrity of layer joining, improved quality of cladding layer surface at keeping corrosion resistance and mechanical properties of double-layer sheets.

1 tbl, 6 ex