Mechanism and Control of Rollover of Hot-rolled Coil

After the stainless steel hot-rolled coil is pickled, a strip of 8-18 mm wide and long strips is commonly found on both sides of the strip, which is called a side turn. Since the rollover cannot be eliminated after cold rolling, it directly affects the surface quality of the cold rolled product, so it is generally trimmed and delivered. In actual production, the width of the rollover should be controlled as much as possible.

Mechanism and causes of rollover formation:
1, Because the large surface of the continuous casting slab is sharpened after grinding, and the side is not ground, after heating and oxidation, the side is rough. After rough rolling, the four corners and the unground metal are extended to the surface. Forming a rollover;
2, The rough rolling vertical roller wears large, and the width of the rollover is widened quickly;
3, The width of the blank material fluctuates greatly, and the trapezoidal direction in the longitudinal direction causes the vertical roll side pressure control to be unstable, the rollover width to be widened, and the side turn over after cold rolling is not clean.

Control measures:
1, The side turn is mainly caused by the surface of the slab not being ground and heated and oxidized, and the surface is roughened, and then rolled to the surface of the strip; if the original slab has a high surface finish, the corresponding heating and rolling process is rough and oxidized. Light, can effectively reduce or not see the rollover phenomenon.
2, During the hot rolling, the rough rolling vertical roll adopts an appropriate side pressure amount, which can reduce the amount of surface rolling of the casting blank to the surface during the vertical rolling process and reduce the rollover width.
3, Continuous casting slab longitudinal side concave casting can significantly reduce the roll width of the steel roll, and with the degree of the undercut, the roll roll width reduction will also change, when the amount of undercut is 3mm, the coil side The effect of reducing the width of the roll is most obvious, and the degree of dispersion of the roll width is also reduced.

Domestically, after taking the above measures, Taigang reduced the average width of the roll roll from 11.2mm to 9.3mm, which improved the utilization of the coil,  and the damage to the crystallizer was small and the effect was good.