How To Solve The Problem Of High-Speed Vibration And Layout Of Wire Rod Finishing Mill

How to solve the problem of high-speed vibration and layout of wire rod finishing mill
1. Functions and requirements of finishing mill
The high-speed wire rod finishing mill is a finishing equipment used in the high-speed wire rod rolling workshop. Its technical level determines the quality of the whole wire rod mill. From the perspective of the birth and development of high-speed rail mill, no matter which form of rolling mill pursues high speed. If so, the vibration problem caused by high-speed operation must be solved.
Methods to reduce vibration:
First, improve the natural frequency of the mechanical transmission system to avoid the resonance phenomenon when working at high speed;
The second is to reduce the height of the mill and the size of the mill, so as to reduce the distance from the running part to the foundation and reduce the volume of the rotating body as much as possible;
Third, eliminate parts that are difficult to control vibration, such as rolling mill coupling, shaft sleeve, coupling, etc;
Fourth, carry out stricter manufacturing quality control and dynamic balance test on running parts.
When the vibration problem is solved, the running speed of the rolling mill can be improved. This is also the most fundamental principle for the design, production, manufacturing and use of high-speed rolling mills. On this basis, many different forms of high-speed units have been produced, each with its own characteristics. After decades of production practice, Morgan models, Danieli models, Simak models and CERI models are currently technically mature and widely used.
As a finishing rolling equipment, the finishing mill must also ensure the accuracy of rolled pieces. Generally, it is required that the sectional dimension accuracy of high-speed wire rod mill products can reach ± 0.1mm (for 5.5 ~ 8mm products) and ± 0.2mm (for 9 ~ 16mm products and wire rods), and the sectional non roundness is not greater than 80% of the total deviation of sectional dimension. In this way, the mill is required to have sufficient rigid structure and wear-resistant rolls.
2. Layout and characteristics of finishing mill
After years of development and evolution, various types of high-speed torsion free wire rod finishing mills have gradually shown convergence in structure and parameters, and have a lot in common:
(1) In order to realize high-speed torsion free rolling, the centralized transmission of the unit is adopted, and the transmission is distributed to two main transmission shafts by a motor or a motor group in series through the speed increasing gearbox, and then the odd and even finishing rolling stands are driven respectively. The roller speed ratio of adjacent frames is fixed, and the roller axes form a 90 ° intersection angle with each other.
(2) In order to make the structure compact and reduce the length of the lost tension section of the rolled piece during micro tension rolling, the center distance of the rack shall be reduced as much as possible.
(3) In order to improve deformation efficiency and reduce deformation energy consumption, smaller roll diameters are used. The roll ring diameters of various high-speed torsion free finishing mills are 150 ~ 230mm, and the roll ring material is tungsten carbide with high hardness and high wear resistance.
(4) In order to facilitate the adjustment and replacement of rolls and guide devices under the condition of small frame center distance, the working base of the rolling mill adopts the form of cantilever rolls, and the fabricated short roll body is used for rolling, and the cemented carbide roll ring with high wear resistance is fixed on the roll shaft of the cantilever with keyless connection. The roll ring is engraved with 2 ~ 4 rolling grooves, and the width of the roll ring is 62 ~ 92mm.
(5) In order to adapt to high-speed rolling and ensure that the roll shaft has the greatest strength and stiffness under the condition of small roll ring diameter, the roll bearing adopts oil film bearing.
(6) In order to adapt to high-speed rolling, the working stand of the rolling mill adopts the rolling symmetrical reduction adjustment method to ensure that the rolling line is fixed.
(7) In order to improve the operation rate of the unit, plug-in roll boxes and special tools for rapid disassembly and assembly of roll rings are used.