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It is composed of roll, mill yard, bearing seat, bearing, built-in rewinding or rewinding platform, base, roll adjusting device, roll balancing device and roll changing device.
Mill Roll
It is a part that causes plastic deformation of metal (see roll).
Roll Bearing
Support the roll and hold the roll in a fixed position in the frame. The roller bearing has a heavy working load and large changes, so the bearing friction coefficient is required to be small, with sufficient strength and stiffness, and it is easy to replace the roll, such as cylindrical roller bearings. Different rolling mills use different types of roll bearings. Cylindrical roller bearings have large rigidity, small friction coefficient, large pressure, convenient roll disassembly, but the price is relatively high. The rolling bearing has large rigidity, small friction coefficient, but small bearing capacity, and large outline size, which is mostly used for plate and strip mill work rolls. Plain bearings have two kinds of semi-dry friction and liquid friction. Semi-dry friction roll bearings are mainly bakelite, copper tile, nylon tile bearings, relatively cheap, more used in profile mill and billet machine. There are three kinds of liquid friction bearings: dynamic pressure, static pressure and static-dynamic pressure. The advantage is that the friction coefficient is relatively small, the pressure capacity is large, the use of high working speed, good rigidity, the disadvantage is that the oil film thickness changes with the speed. Liquid friction bearings are mostly used in back-up rolls and other high speed rolling mills.
Mill Stand
It consists of two "mouth plates" to install the roll bearing seat and roll adjusting device, which must have sufficient strength and steel to withstand the rolling force. The main form of the frame is closed and open. The closed frame is an integral frame with high strength and stiffness, which is mainly used in blooming mills and strip mills with large rolling forces. The roller change guide rail can be arranged under the mouth frame, and the external roller change car is composed to facilitate the roller change.
Stand Base:
Used to install the frame, and fixed on the foundation, also known as the foot board. Withstand the gravity and tipping moment of the working frame, while ensuring the accuracy of the mounting size of the working frame.
Roll adjusting device
It is used to adjust the roll gap to make the rolled parts reach the required section size. The upper roller adjustment device is also called "pressure device", which has three kinds of manual, electric and hydraulic. Manual push-down devices are used in profile mills and small mills. The electric drive down device includes a motor, reducer, brake, drive down screw, drive down nut, drive down position indicator, spherical pad and pressure meter, etc. Its transmission efficiency is low, the rotating inertia of the moving part is large, the reaction speed is slow, and the adjustment accuracy is low. Since the 1970s, after the adoption of AGC(Automatic Thickness Control) system in strip mills, hydraulic pressing devices have been adopted in new strip cold and hot mills and heavy plate mills, which has the advantages of small plate thickness deviation and high product qualification rate.
Upper roll balancing device
A device used to lift the upper roll and protect the rolled piece from impact when moving in and out of the roll. Forms are: spring type, used in the profile mill; Heavy weight type, commonly used in the blooming mill with large roll movement; Hydraulic type, used in four-high strip mill.
In order to improve the working rate, it is necessary to change the rolls quickly and conveniently. There are four kinds of roll changing modes: C-shaped hook type, sleeve type, trolley type and whole frame roll changing type. The first two methods of roll change rely on the crane to assist the operation, and the whole machine frame roll change needs two sets of frames, this method is mostly used for small rolling mills. Trolley roll change is suitable for large rolling mills and is conducive to automation. Today, the mill is using a fast automatic roll change device, a roll change only 5 to 8 minutes.
Driving gear
It is composed of motor, reducer, gear seat and connecting shaft. The gear seat distributes the driving torque to two or more rolls.
Auxiliary equipment
Includes a series of auxiliary process equipment 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 transportation equipment cranes, transport vehicles, rollers and transfer machines, etc.
Accessory equipment
There are supply, distribution, roll grinding, lubrication, supply, drainage, fuel, compressed air, hydraulic pressure, removal of iron oxide, mechanical repair, electrical repair, acid discharge, oil, water, acid recovery, and environmental protection and other equipment.