Abstract: In the 1 780 mm hot rolling mill, Bengang uses advanced thirdgeneration "dual station coreless coiling" hot coil boxes to produce low to medium grade nonoriented silicon steel products. Compared with the conventional 1 700 mm hot rolling mill equipped with insulation covers, the finishing temperature control capability has been greatly improved, enabling the stable implementation of the lowtemperature tapping process. This significantly reduces the solid solution and precipitation of the second phase, avoids its fine dispersed distribution at grain boundaries, forms a favorable hotrolled plate structure foundation, lays the groundwork for obtaining an ideal grain size in the subsequent finished product annealing process, and thus achieves excellent magnetic properties. After the commissioning of the hot coil box, the average finishing temperature increased from 850 ℃ to 880 ℃. Compared with conventional units, the iron loss decreased by 8.3 % and the magnetic induction increased by 0.01 T.

Key words: non-oriented silicon steel, hot coil box, finishing temperature, the second phase, magnetic properties