METHOD FOR PRODUCING COLD-ROLLED ANISOTROPIC ELECTROTECHNICAL STEEL

摘要

The invention relates to the field of ferrous metallurgy. In order to produce cold-rolled anisotropic electrotechnical steel with low losses (?1.7/50 = 1.0 w/kg) and high induction (?800 = 1.90 tesla), steel having a content of 2.5-3.5% by mass of silicon, 0.004-0.013% by mass of nitrogen, and 0.010-0.040% by mass of acid-soluble aluminium is melted, the product is poured into slabs, followed by hot rolling, strip annealing, cold rolling, continuous decarbonizing annealing of the cold-rolled strips, and nitriding and high-temperature annealing. Slabs having a thickness of 220-270 mm are placed into a heating furnace with a surface temperature of at least 450°C, are heated up to 1100-1200°C and rolled. The continuous annealing of a cold-rolled strip is carried out at a heating rate of 20-50°C/sec to 750-800°C, decarbonization is carried out at 790-840°C in an atmosphere with a ratio of P?2/P?2o = 1.9-2.5, heating is carried out to a maximum of 870°C and the product is allowed to settle for 10-30 sec in an atmosphere with a ratio of P?2/P?2o = 1.9-20, nitriding is carried out at 780-850°C in an atmosphere with a ratio of PH2/P?2o = 15-200, heating is carried out to a maximum of 1050°C and the product is allowed to settle for 15-30 sec in an atmosphere with a ratio of P?2/P?2o = 5-500.