Detailed introduction to rolling mill components

The main components of rolling mill equipment

The rolling mill is mainly composed of rolls, rolling mill arches, bearing packages, bearings, worktables, rolling guides, rail seats, roll adjustment devices, upper roll balance devices and roll changing devices.

1. The roll is the part that plastically deforms the metal.

2. Roll bearing

Support the rolls and keep the rolls in a fixed position in the stand. The roller bearing has a heavy working load and changes greatly, so the bearing friction coefficient is required to be small, with sufficient strength and rigidity, and it is necessary to facilitate the replacement of the roller. Different rolling mills use different types of roll bearings.

Rolling bearings have high rigidity, small friction coefficient, but small pressure bearing capacity and large external dimensions, and are mostly used for work rolls of strip mills.

There are two types of sliding bearings: semi-dry friction and liquid friction. The semi-dry friction roller bearings are mainly bakelite, copper tile and nylon tile bearings, which are relatively cheap and are mostly used in profile rolling mills and blanking machines. There are three types of liquid friction bearings: dynamic pressure, static pressure and static-dynamic pressure. The advantage is that the friction coefficient is relatively small, the pressure bearing capacity is large, the working speed is high, and the rigidity is good. The disadvantage is that the thickness of the oil film changes with the speed. Liquid friction bearings are mostly used for back-up rolls in strip mills and other high-speed mills.

3. Rack

The frame consists of two "archways" to install the roll chock and the roll adjustment device, and it needs to have sufficient strength and rigidity to withstand the rolling force. There are two main types of racks: closed and open.

The closed frame is an integral frame with high strength and rigidity, and is mainly used in blooming mills and strip mills with large rolling force. The open frame is composed of two parts: the frame body and the upper cover, which is easy to change the roll, and is mainly used for the horizontal profile rolling mill. In addition, there are no archway mills.

4. Rail seat

It is used to install the rack and is fixed on the foundation, also known as the foot plate. Withstand the gravity and tipping moment of the working machine base, and at the same time ensure the accuracy of the installation size of the working machine base.

5. Roll adjustment device

It is used to adjust the roll gap to make the rolled piece reach the required section size. The upper roller adjustment device is also called "pressing device", and there are three kinds of manual, electric and hydraulic.

Manual reduction devices are mostly used in profile rolling mills and small rolling mills.

The electric pressing device includes electric motor, reducer, brake, pressing screw, pressing nut, pressing position indicator, spherical spacer and pressure gauge and other components. Its transmission efficiency is low, the rotational inertia of the moving part is large, the response speed is slow, and the adjustment accuracy is low.

Since the 1970s, after the AGC (Automatic Thickness Control) system was adopted in the strip mill, the hydraulic pressing device has been adopted in the new strip cold and hot rolling mills and heavy plate rolling mills, which has the advantages of small plate thickness deviation and high product qualification rate. .

6. Upper roll balance device

The upper roll balancing device is used to lift the upper roll and prevent the rolling stock from being impacted when entering and exiting the roll. The forms are: spring type, mostly used in profile rolling mills; heavy hammer type, commonly used in blooming mills with large roll movement; hydraulic type, mostly used in four-high strip mills.

In order to improve the operation rate, the rolling mill is required to change the rolls quickly and easily. There are four types of roller changing methods: C-shaped hook type, sleeve type, trolley type and whole rack roller changing type. The first two methods are used to change the rolls with the aid of cranes, while the whole rack needs to have two sets of racks to change the rolls. This method is mostly used for small rolling mills. The trolley roll change is suitable for large rolling mills, which is conducive to automation. Today, fast automatic roll changing devices are used on rolling mills, and it only takes 5 to 8 minutes to change a roll.

7. Transmission

The transmission device consists of a motor, a reducer, a gear seat and a connecting shaft. The gear base distributes the drive torque to two or more rolls.

Auxiliary equipment includes equipment for a series of auxiliary processes in the rolling process. Such as raw material preparation, heating, turning steel, shearing, straightening, cooling, flaw detection, heat treatment, pickling and other equipment. Lifting and transporting equipment Cranes, transport vehicles, roller tables and transfer machines, etc.

8. Auxiliary equipment

There are equipment for power supply, power distribution, roll grinding, lubrication, water supply and drainage, fuel supply, compressed air, hydraulic pressure, iron oxide removal, machine repair, electrical repair, acid discharge, oil, water, acid recovery, and environmental protection.