1. How to eliminate the waves on both sides and the middle wave by adjusting the flow rate of the emulsion?
Answer: During the rolling process, there are waves on both sides of the strip. In addition to the high rolling pressure on both sides of the strip, the thermal expansion on both sides of the roll is also a reason. At this time, the flow of the emulsion on both sides of the strip should be increased to eliminate the roll. Thermal expansion, thereby eliminating the waves on both sides of the strip.

2. What is hydraulic bending roll?
Answer: Hydraulic roll bending is to apply additional bending force to the work roll or backup roll with a hydraulic cylinder, so that the roll produces additional deflection and compensates for the original roll crown of the roll, so as to ensure the good shape of the strip.

3. How to ensure the good shape of the plate?
Answer: In order to ensure a good plate shape, the principle of uniform extension or the so-called "plate crown" must be followed, that is, the elongation or reduction rate of each upward point along the length of the strip must be basically equal, in order to meet the uniform deformation conditions , to ensure the good shape of the strip, the ratio of the thickness of the strip before rolling to the thickness after rolling must be equal to the elongation, or the convexity of the strip before rolling and the convexity of the strip after rolling must be consistent.

4. What factors are related to the shape of the roll gap of the rolling mill?
Answer: The lateral thickness difference and shape change of the strip are caused by the change of the roll gap shape. The factors affecting the roll gap shape are:
1) Elastic bending deformation of the roll.
2) Thermal expansion of the roll.
3) Wear of the rolls.
4) Elastic flattening of rolls.
5) The original roll shape of the roll.

5. What factors make the actual crown and deflection of the work roll change continuously during the rolling process?
  answer:
1) The length of the rolling work time, the level of the rolling speed, the different types of rolling products, and the difference in the cooling conditions of the rolls will cause changes in the temperature distribution of the rolls, resulting in changes in the thermal crown of the rolls, thus causing the actual crown of the work rolls. degree of change.
2) During the rolling process, the increase of the wear of the roll also causes the change of the actual crown of the roll.
3) Changes in the thickness, width, tension, etc. of the rolling stock and the influence of uneven mechanical properties of the rolling stock, etc., will cause changes in the size and lateral distribution of the rolling pressure, thereby causing changes in the actual deflection of the work rolls.

6. Is the lateral thickness difference of the strip the same as the plate shape?
Answer: The lateral thickness difference of the strip is not the same as the plate shape. The lateral thickness difference is the thickness deviation of the strip along the width direction, which is determined by the cross-sectional shape of the strip. Therefore, the plate shape is determined by the longitudinal extension difference of the strip steel, which is different from the lateral thickness difference, but they are intrinsically related. By adjusting the shape of the roll gap, the purpose of reducing the lateral thickness difference of the strip steel and improving the quality of the plate shape can be achieved.

7. What are the adverse consequences of the operation if the strip tension is too large or too small during the rolling process?
Answer: When selecting the pass plan, the strip tension of each pass must be correctly selected. If the strip tension is not selected properly, it will affect the strip quality and actual operation. It will cause the strip to be broken or the inner diameter of the coil after rolling is "chicken-hearted". If the tension is too small, it will cause the roll or the strip to deviate and the strip to break and damage the roll.

8. Why should double-frequency quenching be performed on cold-rolled work rolls? What is the principle of double frequency quenching?
Answer: The rolling force is very high in cold rolling production. In order to reduce the rolling force and ensure the quality of the strip, the hardness of the cold rolling work roll body must be guaranteed to be above Shore hardness (HS) 90. Therefore, the cold rolling work roll It must be quenched to improve the surface hardness. Double-frequency quenching is a method of quenching the surface of the roll with double-frequency heating. Heating and heating for quenching.

9. What characteristics does the tandem cold rolling mill require the motor to meet?
  answer:
1) The rolling mill is required to have a large speed regulation range, and it is required to be continuously adjustable.
2) The rolling mill speed of each stand can be started, braked and run forward and reverse independently, and can be braked together.
3) In order to ensure smooth belt threading, the characteristics of the motor should be hard enough, and the dynamic speed of the motor should not be greater than 25%. In order to ensure smooth belt threading and establish tension, a speed fine-tuning device must be provided.
4) In various operations of strip threading, acceleration, steady-speed rolling and deceleration, the required strip tension should be ensured and tension fluctuations should be reduced.

10. What effect does the size of the roll diameter have on the rolling process?
  answer:
1) The roll diameter is too small, which reduces the adjustment effect of the bending roll, and the plate shape is difficult to control.
2) The roll diameter is too small, exceeding the depth of the hardened layer on the surface of the roll, and the surface hardness of the roll is small. On the one hand, there are many soft spots, which affects the surface quality; on the other hand, the contact arc area of the deformation zone increases, and the rolling force increases.