Brief Introduction of Roll Gap Shape Equation of Rolling Force of Packaging Steel Strip

Brief Introduction of Roll Gap Shape Equation of Rolling Force of Packaging Steel Strip
　　 The rolling force distribution is set as a quadratic curve along the transverse direction (the direction of the roll body) and uniformly distributed along the longitudinal direction (the direction of the contact arc), so that the roller bending burn differential equation can be listed for the work roll and support roll. For rolls with a large ratio of diameter to roll body length, the differential equation of shear deflection should also be listed. The differential equation is solved and the roll flattening is added to obtain the shape of the loaded roll gap, such as the mark point with the edge and the point at the middle of the belt. For the representative (convexity), the Kf values u200bu200bof the rolling force transverse stiffness and the bending force transverse stiffness can be obtained respectively.
　　Theoretical calculations are more complicated on the one hand, and on the other hand, some assumptions are not completely in line with reality. Therefore, it is more useful for specific rolling mills to obtain Kp and Kf through transverse stiffness test of steel plates.
　　 It is a more intuitive method to express the shape of the strip section or the shape of the seam of the loaded rod with the convexity, which better reflects the quadratic term (parabola) in the shape of the seam of the loaded rod. For the shape setting model, since the actuator has only bending rolls and shifting rolls, the concept of crown is generally adopted.
　　 But for the flatness feedback control system, while considering the crown, it is necessary to further consider the fourth-order term in the section shape of the strip for segmented cooling control.
　　 Even so, because the main component of the strip profile curve is the quadratic term, the convexity is still an important indicator for us to discuss the shape problem in the future.
　　 The crown equation reflects the influence of various factors on the (loaded) roll gap shape. The measures used in cold tandem rolling to control the export crown are:
　　 (1) Four-roll CVC or other roll profile curves, when the rolls move, the roll crown, that is, the roll gap shape, can be adjusted.
　　 (2) Six-roll HC, when the middle roll moves, the stress state will be changed. Under the action of rolling force and roll bending force, different loaded roll gap shapes will be produced.
　　 (3) The roll bending mechanism directly changes the shape of the roll seam by adjusting the bending deformation of the roll.
　　 (4) The modification of both sides of the support roller can improve the edge thinning on the one hand, and also improve the ability of the roll bending mechanism.
　　(5) The rolling roll is cooled in sections, and the roll gap shape is adjusted by changing the hot roll shape.
　　(6) Reasonable distribution of rolling pressure will create a good foundation for other flatness control methods.
　　 (7) Reasonable design of the original cold roll shape.
　　 The main disturbances affecting convexity are:
　　 (1) The fluctuation of rolling force, especially the large milking force fluctuation that occurs during AGC operation.
　　 (2) The fluctuation of the hot roll shape.
　　 (3) Wear of rolls.
　　 (4) The variation of the convexity of the incoming material.
The goal of 　　 shape control is to control the convexity (relative convexity) of the exit of each frame:
　　 (1) to ensure the convexity of the finished product.
　　 (2) to ensure the relative convexity of each frame outlet is constant, that is, to maintain a good flatness or uniform transverse tensile stress distribution.