	US 12,392,009 B2
	High-grade non-oriented silicon steel and production method thereof
Chongxiang Yue, Suzhou (CN); Shengjie Wu, Suzhou (CN); Jiadong Lu, Suzhou (CN); and Hui Li, Suzhou (CN)
Assigned to INSTITUTE OF RESEARCH OF IRON AND STEEL, JIANGSU PROVINCE/SHA-STEEL, CO. LTD (CN), Jiangsu (CN); ZHANGJIAGANG YANGTZE RIVER COLD ROLLED PLATE CO. LTD, Jiangsu (CN); and JIANGSU SHAGANG GROUP CO., LTD., Jiangsu (CN)
Appl. No. 18/247,814
Filed by INSTITUTE OF RESEARCH OF IRON AND STEEL, JIANGSU PROVINCE/SHA-STEEL, CO. LTD (CN), Jiangsu (CN); ZHANGJIAGANG YANGTZE RIVER COLD ROLLED PLATE CO. LTD, Jiangsu (CN); and JIANGSU SHAGANG GROUP CO., LTD., Jiangsu (CN)
PCT Filed Jul. 19, 2021, PCT No. PCT/CN2021/107028 § 371(c)(1), (2) Date Apr. 4, 2023, PCT Pub. No. WO2022/127104, PCT Pub. Date Jun. 23, 2022.
Claims priority of application No. 202011486898.X (CN), filed on Dec. 16, 2020.
Prior Publication US 2023/0332264 A1, Oct. 19, 2023
Int. Cl. C23G 1/08 (2006.01); B22D 11/00 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 9/52 (2006.01); C22C 33/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/34 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01)

CPC C21D 9/52 (2013.01) [B22D 11/001 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C21D 8/0278 (2013.01); C22C 33/04 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/004 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/34 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C23G 1/08 (2013.01); C22C 2202/02 (2013.01)]

8 Claims

1. A production method of non-oriented silicon steel, comprising the following steps:

1) Smelting steel by molten iron desulfurization, converter smelting and RH refining in sequence, to obtain a molten steel comprising the following chemical components in percent by mass: 0.002-0.004% of C, not greater than 0.003% of S, 1.4-1.7% of Si, 0.7-0.95% of Mn, not greater than 0.03% of P, 0.015-0.035% of Sn, not greater than 0.004% of Nb, not greater than 0.004% of V, not greater than 0.005% of Ti, not greater than 0.004% of Mo, not greater than 0.03% of Cr, not greater than 0.03% of Ni, not greater than 0.03% of Cu, not greater than 0.003% of N, and the balance Fe and inevitable impurities, and 11×([Si]-1.4%)=14×([Mn]-0.7%);

2) Continuously casting the molten steel obtained in step 1 into a continuous casting billet with a thickness of more than 200 mm;

3) Heating the continuous casting billet obtained in step 2 to reach a temperature between 1,120-1,150° C., and maintaining the temperature for more than 200 min; then carrying out multi-pass rough rolling to obtain an intermediate billet with a thickness of 40-45 mm; and then carrying out multi-pass finish rolling, cooling and coiling to obtain a hot-rolled coil with a thickness of 2.50±0.1 mm, the finishing temperature in finish rolling being 890±15° C., the rolling reduction of the last pass of finish rolling being not less than 30%, the total rolling reduction of the last two passes of finish rolling being not less than 50%, and the coiling temperature being 650±20° C.;

4) Carrying out uncoiling, acid pickling, rinsing, drying, cold rolling and coiling on the hot-rolled coil obtained in step 3, rather than carrying out normalizing treatment, thereby obtaining a cold hard coil with a thickness of 0.500±0.005 mm or 0.350±0.004 mm; and

5) Carrying out finished product annealing on the cold hard coil obtained in step 4 in a mixed atmosphere of H₂+N₂through a continuous annealing furnace, the finished product annealing temperature being 920-980° C., and the annealing time being 60±5 s; and carrying out cooling, coating and finishing on the annealed steel strip to obtain a finished product of non-oriented silicon steel.