Abstract: Taking advantage of the equipment renovation and control system upgrade of the Beiying 1 780 hot rolling unit, we have developed a production process for cold rolling of low and medium grade non oriented silicon steel hot rolling base materials for sheet metal. With the stability of the production process and the increase of output tasks, a large number of hole defects appear in the cold rolling process, causing huge cutting losses and seriously affecting the yield rate. Measures were taken to sample and inspect defects, uncoiler hot-rolled coils, track and compare hot-rolled gauges, and study equipment influencing factors to confirm the source of defects. These measures included changing the material of the guide strip lining for precision rolling and coiling, changing the guide strip control mode and reducing pressure, optimizing the opening degree of the guide strip upstream and downstream of the precision rolling mill, and optimizing the strip centering in finishing mill stands. As a result, the degradation rate of holes was reduced from 19.46 % to 1.65 %, significantly improving the yield rate.

Key words: non-oriented silicon steel, holes, degradation rate