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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

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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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?

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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08

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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Development course of roll material and heat treatment process

The service life of the roll mainly depends on its internal performance and working stress, and the internal performance includes strength and hardness. In order to make the roll have sufficient strength, the material of the roll should be considered. Hardness usually refers to the hardness of the working surface of the roll, which determines the wear resistance of the roll, and to a certain extent also determines the service life of the roll. Reasonable material selection and heat treatment can meet the hardness requirements of the roll. Below, the small series will bring you together to understand the development of roll materials and heat treatment processes. What many people don't know is that the cold roll bears a lot of rolling pressure during the working process, and the welding seam, inclusion, edge crack and other problems of the rolled piece are easy to lead to instantaneous high temperature, which makes the working roll crack, stick the roll and even peel off and scrap due to strong thermal impact. Therefore, the cold roll should have the ability to resist cracking and spalling caused by bending, torsion and shear stress, and should also have high wear resistance, contact fatigue strength, fracture toughness and thermal shock strength. Therefore, from the late 1970 s to the mid-1980s, domestic and foreign research began to use chromium content of 3% to 5% of the deep-hardened layer cold-rolled work roll steel. However, these steels are high-carbon and high-alloy materials with good hardness and wear resistance, but the hardened surface of the roll is brittle, the contact fatigue life is short, and the quality is unstable.

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