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Classification of rolls

Classification of rolls

Classification of rolls There are many classification methods for rolls, mainly including:(1) according to product types, they are divided into strip steel rolls, special-shaped steel rolls, wire rod rolls, etc. (2) according to the position of the rolls in the rolling mill series, there are open rolls, rough rolls, fine rolls, etc. (3) according to the roll function, it is divided into scale breaking rolls, perforated rolls, leveling rolls, etc. (4) according to the material of the rolls, there are steel rolls, cast iron rolls, carbide rolls, ceramic rolls, etc.;(5) according to the manufacturing method is divided into casting rolls, forging rolls, surfacing rolls, inlaid rolls, etc.;(6) according to the state of rolled steel is divided into hot rolls and cold rolls. Various categories can be combined accordingly, so that the roll has a clearer meaning, such as centrifugal casting of high chromium cast iron work rolls for hot strip steel. Common drum materials and uses are shown in the table. The performance and quality of a roll generally depends on its chemical composition and manufacturing method, and can be evaluated by its microstructure, physical and mechanical properties, and the type of residual stress inside the roll (see roll inspection). The effect of the roll on the rolling mill depends not only on the material and metallurgical quality of the roll, but also on the conditions of use of the roll, roll design, operation and maintenance. The rolling conditions vary greatly for different types of mills. The factors contributing to the difference are:(1) mill conditions. such as mill type, rolling

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Precautions for installation and use of roll ring

Precautions for installation and use of roll ring

Precautions for installation and use of 1. roller rings The following points should be paid attention to in the installation of carbide roller rings: 1. The roller ring machine should strictly check the size of the roller ring according to the process design requirements. In order to ensure the same batch of roller rings, it is more suitable for the same batch of attack with the same brand of roller rings, matching roller ring material. The performance and density should be consistent. If there is a difference, it will affect the dynamic balance and the use effect of the roller ring. 2. Roller ring installation and roller ring. The matching surface between the roller shaft and the roller cone sleeve and the sleeve should be kept clean, and the matching place should be kept clean and reasonable. The assembly should not be too tight or too loose. If the assembly is too tight, the rolling temperature will increase. At this time, the roller ring is in a state of large tensile stress, once the rolling force is shaken, it will cause the roller ring to crack radially, so that the roller ring is cracked and scrapped. If the combination is too loose, the roller ring and the roller shaft will slide relative to each other, resulting in frictional heat, resulting in thermal stress and cracks in the roller ring. In severe cases, the roller ring and the roller shaft taper sleeve can be discarded. Therefore, the installation pressure of the roller ring should be strictly controlled. 3. Roll ring is a brittle material. It is heavy and easily damaged. Therefore, collision is strictly prohibited during the installation, transportation and handling of the roller ring. Wait. 2. reasonably determine the rolling volume roll ring single groove rolling to a certain time. When the rolling groove produces a

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Key points of roll ring assembly

Key points of roll ring assembly

In the actual use process, there are many factors that affect the assembly of the roller ring. Improper assembly operation will cause the roller to burst, the roller to loosen, the cone sleeve to break and other production failures. Therefore, the factors affecting the assembly of the roller ring are classified and analyzed, and the reasonable loading and unloading pressure range of the roller can effectively avoid the occurrence of accidents such as roller burst, roller loosening and cone sleeve fracture. According to the structure of the roller ring of the high-speed wire rod mill, the factors affecting its assembly are analyzed. The geometric dimensions of the roller ring, taper sleeve, roller shaft, roller changer and roller press machine directly affect the assembly of the roller ring and are more important factors. The roller ring is made of WC material, and the hardness of HRC reaches 83. It is a kind of high wear-resistant material. The center hole of the roller ring is in contact with the outer ring of the taper sleeve, so the fit tolerance between the center hole of the roller ring and the taper sleeve is a very critical parameter. The inner circle of the taper sleeve is in direct contact with the roller shaft, and the interference fit is adopted. The taper of the inner circle of the taper sleeve should be consistent with the taper of the roller shaft and should not exceed the tolerance range. Otherwise, the contact area between the inner ring of the cone sleeve and the roller shaft will be affected, and the contact surface should be greater than 70%. The roller puller and pressure roller of the roller changing car are matched with the four ears of the taper sleeve to complete roller loading and unloading through the set pressure value. Drum machine and drum press with cone ear fit, size

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Introduction of roll ring

Introduction of roll ring

The roller ring is a part of the shaped roller body between the grooves or outside the grooves. The end roller rings located at both ends of the roller body can prevent the oxidation sheet from falling into the bearing; the intermediate roller ring located between two adjacent channels is mainly used to separate the channel and bear the lateral pressure. The basic parameters of the roll ring are the height of the roll ring and the width of the roll ring. The height of the roller ring is the depth of the groove. When determining the width of the middle roller ring, the strength of the roller ring and the convenience of installation and adjustment of the guide device are mainly considered. The end roller rings located at both ends of the roller body can prevent the oxidation sheet from falling into the bearing; the intermediate roller ring located between two adjacent channels is mainly used to separate the channel and bear the lateral pressure. The basic parameters of the roll ring are the height of the roll ring and the width of the roll ring. The height of the roller ring is the depth of the groove. When determining the width of the middle roller ring, the strength of the roller ring and the convenience of installation and adjustment of the guide device are mainly considered. The strength of the ring depends on the material of the roller and the depth of the groove. The width of the middle roll ring of the cast iron roll open channel is generally equal to the depth of the groove in the middle of the two adjacent channels, which can be appropriately reduced for steel rolls or short rolls. In the closed roll, when the roll material is cast steel, the roll ring width can reach 0.8~1.0 times of the groove depth, and the cast iron roll can reach 1.2~1.5 times of the groove depth. When selecting the ring width,

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2022

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Roller bearing related content sharing

Roller bearing related content sharing

Maintenance of roll bearings The roll bearings need to be taken out of the rolling mill regularly for inspection and maintenance to improve the service life of the roller bearings. The frequency of bearing maintenance should be adjusted according to the operation of the rolling mill, mainly based on experience. The usual maintenance frequency is once every three months at full load, most rolling mills once every six months, and light rolling mills once a year in December. After the first 1000 hours of operation, the roller bearings should be disassembled and inspected. During operation, it is necessary to clean the bearing and check the oil seal. If necessary, replace the oil seal completely. If no abnormality is found, the interval of the secondary examination may be extended. The general steps for roll bearing maintenance are: 1. Track and record the position of the bearing in the mill. It is recommended to use a special record card for roller bearing maintenance services. It is also necessary to pay attention to special lifting methods and tools when removing the bearing from the bearing seat or inspecting the bearing. 2. Clean the bearing. During the cleaning of the bearing, all flaking, water, residual lubricant and any other dirt that can cause serious bearing wear should be removed. 3. Check the bearings, including visual inspection and minor repairs. Pay attention to check and repair the bearing seat, and put the bearing back into the bearing seat as needed. 4. Lubricate the bearing. The existing common mill has the characteristics of large rolling force and high rolling speed, which requires lubrication.

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Rolling mill roll bearing failure analysis and countermeasures?

Rolling mill roll bearing failure analysis and countermeasures?

The roll bearing mill is developed on the basis of replacing the bearing bush used before. Compared with the bearing mill, its stability has been greatly improved. At present, my country's rolling mills need to widely use bearings to replace bearing bushes, but it is found that roll bearings often fail during use, which will have a great impact on production. According to statistics, the main factors that cause the failure of the roller shaft are: assembly influence, improper lubrication influence, improper protection of foreign matter and overload. The following will analyze the causes of roll bearing failure and introduce measures to reduce roll bearing failure. 1. Failure caused by improper assembly of roll bearing One end of the roll bearing is composed of four-row centripetal short column roll bearing and single-row centripetal ball bearing. In the steel rolling production process, the radial force is mainly the main rolling force and the radial force generated during the rolling process, and the axial force generated during the rolling process. The radial force is shared by the two bearings, and the axial force is mainly borne by the single row radial bearing. Through analysis, it is found that this bearing distribution method has high carrying capacity, bearing size is smaller than other bearing methods, and shaft positioning is more accurate. In particular, the four-row short cylindrical bearings have high centering performance and high manufacturing accuracy. After consulting the bearing manual, it is found that the bearing clearance is less than 0.25mm, which can meet the requirements of multiple disassembly. Solution

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$What is the reason for the fracture of the finishing roll ring?$

What is the reason for the fracture of the finishing roll ring?

At present, the high-speed wire rod finishing roller is generally composed of 8 to 10 rolling mills. The rolling force and impact force of each rolling mill are different. With the increase of rolling passes, the rotation speed of the roll ring will be greatly increased, and the wear of the roll ring will also increase. Therefore, the rolling force is selected for each rolling mill. When the material is used, the impact force and wear resistance of each rolling mill should be fully considered. Otherwise, improper material selection will lead to roll collapse during finish rolling, and the cause of roll collapse is not easy to be identified. For each rolling mill in finish rolling, due to the large cross-sectional size and deformation of the rolled piece, the rolling load and the large impact force on the front stand roll ring, the roll rings of the first few rolling mills of the finish rolling mill should be made of materials with high strength index and good thermal fatigue resistance, and the wear resistance index should be ranked second; however, the rolling load and impact force of the rear frame roll ring are small, so the wear resistance and thermal fatigue resistance of the roll ring should be given priority. Jitter of internal rolling pieces and steel stacking during finishing roll: 1. Poor roll matching of rolling rings The high-speed wire rod mill has strict requirements on the finishing inner roll ring, because the high-speed wire rod finishing mill is driven by a 6000 kW variable frequency AC speed regulating main motor. The gear transmission ratio between the racks is fixed and cannot be changed. It is impossible to adjust the speed of a unit. The finishing mill is required not only to meet

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