In the process of iron and steel metallurgical production, rolling mill is one of the key equipment to realize metal plastic deformation. The adjustment of roll gap is an important link to ensure product quality, improve production efficiency and ensure the safe operation of equipment. Roll gap refers to the gap between rolls, which directly affects the thickness, shape and surface quality of rolled products. Therefore, it is very important for technicians engaged in steel rolling to master the correct method of roll gap adjustment.
First, the importance of roll gap adjustment
The adjustment of the roll gap directly affects the reduction of metal, thus determining the thickness size of the finished product. If the roll gap is set improperly, it will lead to product size deviation, bad shape, and even equipment overload, roll breakage and other accidents. In addition, unreasonable roll gap will increase energy consumption, reduce production efficiency and affect the service life of equipment. Therefore, accurate and timely adjustment of roll gap is a prerequisite to realize stable rolling and ensure product quality.
Second, the main way of roll gap adjustment
1. Manual adjustment
In some small or old equipment, the roll gap is still adjusted manually. The operator adjusts the distance between the upper and lower rollers by rotating the lead screw or hydraulic device. This method is simple to operate, but its accuracy is low, and it depends on the experience of operators.
2. Electric adjustment
Modern plate and strip mills mostly adopt electric screwdown system. The motor drives the reduction mechanism to drive the screw down, so as to realize the automatic adjustment of the roll gap. This method has high adjustment precision and fast response, and is suitable for continuous production.
3. Hydraulic adjustment
Hydraulic screw-down system is a widely used way in high-precision rolling mill at present. Controlling the roll gap by hydraulic cylinder has the advantages of fast reaction speed, accurate pressure control and easy automatic control, and is suitable for production occasions with high requirements on plate thickness.
Third, the operation steps of roll gap adjustment
1. Pre-adjust the roll gap
Before changing the roll or specifications, the size of the roll gap is preset according to the product specifications. Calibration is usually carried out by means of a template or thickness gauge.
2. No-load commissioning
When not rolling, let the roll idle first, check whether the roll gap is uniform, and ensure the synchronization of the screw-down mechanisms on both sides.
3. Belt adjustment
At the beginning of rolling, the metal passing through the roll is observed, and the data is fed back in real time by the thickness gauge, and the roll gap is finely adjusted to achieve the target thickness.
4. Online automatic control
In the highly automated rolling line, AGC (Automatic Thickness Control) system is adopted, and the dynamic adjustment of roll gap is realized through sensors and PLC control system to ensure the stable product quality.
Fourth, matters needing attention
-When adjusting the roll gap, the reduction on both sides should be consistent to prevent unbalanced load.
-Before adjustment, check the screw-down mechanism, transmission system and lubrication condition to ensure that there is no abnormality.
-Under the conditions of high temperature and high load, the thermal expansion gap should be reserved appropriately.
-After adjustment, trial rolling should be carried out, and it can be put into mass production only after the size is qualified.
V. Conclusion
With the development of metallurgical technology and the improvement of automation level, roll gap adjustment is gradually developing from traditional empirical operation to intelligent and digital direction. Whether it is manual adjustment or automatic adjustment, operators need to have solid professional knowledge and rich practical experience, so as to improve product quality and production efficiency on the premise of ensuring safety. Roll gap adjustment is not only a technical activity, but also an artistic activity, which is an important bridge between equipment and technology.