A PREPARATION METHOD OF ORIENTED HIGH SILICON STEEL

摘要

The preparation method includes steps of (1) melting steel according to in weight percentage 0.001-0.003% of C, 5.0-6.6% of Si, 0.2-0.3% of Mn, 0.05-0.12% of Al, 0.01-0.04% of V, 0.03-0.06% of Nb, 0.02-0.03% of S, 0.009-0.020% of N, O which is less than or equal to 0.0020%, and the balance being Fe and unavoidable impurities; (2) forming cast strips after a thin-strip casting course; (3) hot-rolling the cast strips under inert atmosphere conditions; (4) cooling the hot-rolled cast strips to 550-600 DEG C, coiling and performing low-temperature hot rolling/warm rolling on the coiled cast strips under a nitrogen atmosphere condition; (5) removing oxidized scales though pickling, performing cold rolling multiple times; (6) performing recrystallization annealing, coating with an MgO layer, and coiling; (7) performing purification annealing under hydrogen circulation conditions; and (8) removing oxidized scales, coating with an insulating layer, performing flat stretch annealing, and air-cooled coiling.

主权项

1. A preparation method of oriented high silicon steel, being performed according to the following steps of:
(1) smelting to obtain molten steel according to set components in percentage by weight: 0.001-0.003% of C, 5.0-6.6% of Si, 0.2-0.3% of Mn, 0.05-0.12% of Al, 0.01-0.04% of V, 0.03-0.06% of Nb, 0.02-0.03% of S, 0.009-0.020% of N, 0 which is less than or equal to 0.0020%, and the balance being Fe and unavoidable impurities; (2) performing a thin-strip casting course: enabling the molten steel to be charged from a gate into a tundish which is preheated at the temperature of 1200-1250 DEG C, controlling the superheat temperature to be at 20-50 DEG C, and through the tundish, enabling the molten steel to enter a thin-strip casting machine and to be formed into cast strips of which the thickness is 1.8-3.0 mm; (3) after drawing out cast strips, cooling the cast strips to 1000-1050 DEG C at the cooling rate of 50-100 DEG C/s under inert atmosphere conditions, then performing hot rolling, wherein the primary rolling temperature is 1000-1050 DEG C, the final rolling temperature is 900-980 DEG C, and the rolling reduction is 10-15%, and forming hot-rolled cast strips; (4) cooling the hot-rolled cast strips to 550-600 DEG C at the cooling rate of 20-30 DEG C/s, coiling the cooled cast strips, then performing hot rolling/warm rolling on the coiled cast strips at low temperature under a nitrogen atmosphere condition, wherein the primary rolling temperature is 755-765 DEG C, the final rolling temperature is 550-600 DEG C, and the total rolling reduction is 70-80%, and forming warm-rolled strips; (5) removing oxidized scales of the warm-rolled strips through pickling, and then performing cold rolling for multiple times at 100-200 DEG C, wherein the total rolling reduction is 60-80%; during the cold rolling course, performing aging treatment twice to 3 times, wherein the aging treatment temperature is 280-320 DEG C, and the duration is 240-300 s, and performing the aging treatment each time between two adjacent cold rollings, so as to obtain cold rolled strips; (6) performing recrystallization annealing on the cold rolled strips at 840-860 DEG C for 120-180 s under the condition of nitrogen-hydrogen mixed atmosphere, wherein the dew point of the mixed atmosphere is controlled at 30-60 DEG C, then coating with an MgO layer, and finally coiling so as to obtain coated cold-rolled strips; (7) putting the coated cold-rolled strips into a ring furnace at 390-410 DEG C, under the hydrogen circulation condition, firstly heating the coated cold-rolled strips to 990-1010 DEG C at the rate of 30-40 DEG C/h, then heating the heated coated cold-rolled strips to 1120-1140 DEG C at the rate of 10-20 DEG C/h, then heating the heated coated cold-rolled strips to 1220-1240 DEG C at the rate of 30-40 DEG C/h, and keeping the temperature for 20-30 h for purification annealing; and (8) performing surface cleaning on the coated cold-rolled strips after purification annealing so as to remove the oxidized scales, then coating with an insulating layer, performing flat stretch annealing at 790-810 DEG C, finally performing air-cooling to be at 650 DEG C or below and coiling so as to obtain the oriented high silicon steel.