Rolling mill is the equipment that realizes the metal rolling process, which refers to the equipment that completes the entire process of rolling material production. It is mainly composed of unwinding machine, roll pressing system, driving system, hydraulic system, control system, and roll-removing device.
The machine can be classified according to the arrangement and number of rolls, and can be classified according to the arrangement of the rack.
Two rolls Simple structure and wide application. It is divided into reversible and irreversible. The former includes primary rolling mills, rail beam rolling mills, and medium plate rolling mills. There are irreversible slab rolling mills, tandem sheet rolling mills, sheet or strip cold rolling mills, and levelers.
Three rolls Rolls are rolled alternately from the upper and lower roll gaps to the left or right, and are generally used as section steel rolling mills and rail beam rolling mills. This mill has been replaced by a high-efficiency two-high mill.
Lauter three rollers The upper and lower rollers are driven, the middle roller floats, and the rolled material passes alternately from above or below the middle roller. Due to the small diameter of the middle roll, the rolling force can be reduced. Commonly used for rolling rail beams, section steel, medium and heavy plates, and also used for small steel ingot blanking. Such rolling mills are gradually being replaced by four-high rolling mills.
Four roller The work roll has a small diameter and transmits the rolling moment. The rolling pressure is borne by the backup roll with a larger diameter. This kind of rolling mill has the advantages of high relative rigidity, large rolling reduction, small rolling force, and can roll thinner plates. There are two types of reversing and continuous rolling, which are widely used as medium and heavy plate rolling mills, hot and cold rolling mills for strips and flat rolling mills.
Five rolls There are two types: one is a CBS (contact-bend-straighten) rolling mill, which is a four-high rolling mill with a small diameter (1/20 of the work roll) idler roll that bends the rolled product, which is pressed down The volume is many times larger than the usual four-high rolling mill. The rolled part undergoes plastic bending deformation around small idle rollers, which can roll difficult-to-deform metal and alloy strips. The other is that the position of the middle small roll can be adjusted along the entrance or exit of the rolling mill to maintain the correct thickness of the rolled product. It is used to roll stainless steel, carbon steel and non-ferrous metal strips with small thickness tolerances.
HC High-performance rolling mill with controlled roll profile. It is equivalent to add a pair of axially movable intermediate rolls between the work rolls and backup rolls of the four-high rolling mill, and adjust the corresponding ends of the two intermediate rolls to the positions corresponding to the two edges of the strip, so as to improve The uniformity of the pressure distribution and the elastic flattening of the work roll ensures the dimensional accuracy of the strip and can reduce defects such as ultra-thinness and cracking at the edges. HC rolling mill is suitable for cold-rolled wide band steel.
Partial eight rolls It is a variant of a four-high rolling mill. The work roll diameter is 1/6 of the back-up roll, and it is relatively offset to prevent the horizontal bending of the work roll. The rolling force is half of that of the four-roll mill. The work roll has good stability and high horizontal rigidity, and can be used to roll some products that must be rolled with a 20-roll mill. Its structure and adjustment are much simpler than those of a twenty-high mill. This type of rolling mill can be converted into two, four, eight, and sixteen rolls, which is suitable for the needs of many varieties, so it is also called a multi-purpose rolling mill. It is available in reversible and continuous rolling for cold-rolled hard-to-deformed steel, silicon steel and non-ferrous metal strip.
Six rolls It consists of a pair of work rolls and two pairs of backup rolls, and has a relatively stable roll system. However, its rigidity is similar to that of a four-high rolling mill, and its operation is inconvenient, so it is not widely used. It is generally used for rolling copper strips of high-precision submarine cables.
Multi-roller There are three types of twelve, twenty and thirty-six rolls. The pair of rolls with the smallest diameter in the middle of the rolling mill are work rolls, and the rest are backup rolls. It has the advantages of high relative rigidity, large reduction, small rolling force, and extremely thin strips. The initial multi-roll mill was driven by work rolls, and later by intermediate support rolls. It can roll foil with a width of 200 ～ 1000mm and a thickness of 0.02 ～ 0.0015mm.
universal It consists of a pair of horizontal rollers and vertical rollers, all of which are driven by power. For rolling slabs or flat steel.
Universal steel beam The structure is similar to the universal rolling mill, except that the axis of the vertical roll and the horizontal roll are placed in the same vertical plane, and the vertical roll is driven. Suitable for rolling wide-beam steel beams with a height of 300 to 1200 mm.
Disc punch The axis of the rolled product is lower than the axis of the disc. When the disc rotates, the rolled product advances spirally against the mandrel, and the solid round steel top is rolled into a hollow rough tube. It is suitable for rolling 60 to 150 seamless steel tubes. Another type of oblique rolling piercing machine, whose drum-shaped rolls intersect and rotate obliquely, has a working principle similar to that of a disc piercing machine, and is suitable for rolling 60 to 650 seamless steel pipes. The oblique rolling perforating machine is matched with the automatic pipe rolling machine, the sizing mill, the sizing (reducing) machine and the inclined roll straightening machine in FIG. 7 as a seamless steel pipe hot rolling unit.
Wheel hub The inner and outer circles of the wheel rim are rolled by a pair of vertical rolls, and the two end faces of the rim are rolled by a pair of inclined tapered rolls. Inner and outer rings for rolling wheels or rolling bearings.
Sphere The ball rolling mill has spiral semi-circular grooved rolls, and the bar material is spirally advanced between the rotating rolls to be rolled into a ball. The ball with a diameter of 60 to 650 mm can be rolled.