METHOD OF HEAT TREATMENT OF COLD-ROLLED STRIPS OF ISOTROPIC ELECTRICAL STEEL Russian patent published in 1997 - IPC

FIELD: metallurgy. SUBSTANCE: production of cold-rolled strip 0.5 mm thick of electrical cold-rolled isotropic steel from the metal containing, mas. %: silicon 0.8-3.3; aluminium 0.1-0.5; carbon 0.03-0.06, manganese 0.1-0.5; phosphorus 0.005-0.15; sulfur not in excess of 0.006; chromium and nickel - each not in excess of 0.06; copper not is excess of 0.15; the balance, iron; is carried out according to technology with use of units of continuous annealing. In this case, hot-rolled strips up to 2.5 mm thick after heat treatment, or without it and pickling are subjected to cold rolling for final thickness. After cold rolling, the strips in continuous annealing line are degreased, washed and subjected in continuous furnace to decarburizing annealing at temperature of 800-1050 C in nitrogen-hydrogen atmosphere with regulated reduction, as carbon concentration in metal decreases, of water vapor- hydrogen content ratio :=0.36-0.006, and heating up to temperature of beginning of decarbonization is carried out in the atmosphere with :=0.4-0.6. EFFECT: higher efficiency. 3 tbl