What’s the Role of Hot Rolling Mill in Steel Rolling?

The technology of hot rolling mill is to connect the two processes of solidification and deformation of steel, and continuously send the continuous casting slab to the finishing mill in the hot state to directly roll the strip into the coil product. The role and development of hot strip mill group in rolling production, the annual output of workshop is the same as that of continuous hot strip mill, slab or continuous casting slab with thickness of 150-350mm is used in the hot rolling mill.

In the continuous reheating furnace, after the slab is heated to the rolling temperature, the oxide scale on the surface of the slab is first removed at the vertical roller descaling stand of the roughing rolling mill. After each working stand of roughing mill, the strip is rolled into a long strip with a thickness of 25-60mm. The strip ends are cut off by flying shear and sent to the finishing mill with 6-7 four high continuous rolling mills to form the strip of finished product thickness. After cooling to 550-650 ℃, the coil is rolled into steel coil, which is sent to the hot rolling coil warehouse for storage by chain conveyor. After cooling to normal temperature, the cross-cutting unit or longitudinal cutting unit of finishing section is cut into hot-rolled steel plate or narrow-band steel coil with fixed length after uncoiling, straightening, leveling and shearing to meet the needs of industrial production.  

Hot continuous rolling mills can be divided into continuous type, semi-continuous type, three-quarters continuous type, etc.  

The continuous hot strip mill has 11-13 working stands except for the vertical stand, which are all irreversible. Each stand is rolled once. According to the composition of workshop equipment and the power of the main motor, the annual output of the rolling mill is about 2-6 million tons.

Semi-continuous hot strip mill, in addition to vertical roller descaling machine and a two-high irreversible mill, uses a reversible four high mill to repeatedly roll, carry out several times of reduction, roll into strips and send them to the finishing mill, and roll into coils after finishing. There are 7-9 working stands in total. The annual output of rolling mill is about 1-2.5 million tons according to different equipment capacity.

In the roughing mill of three-quarters continuous hot strip mill after the 1960s, one four-high or two high reversing mills is used to replace three four high irreversible mills. The other rolling equipment is the same as the continuous mill, which can reduce equipment weight, shorten workshop length and reduce construction investment.