Cascade control method for controlling rolling warping of small steel billet

Abstract

The invention relates to a cascade control method for controlling the rolling warping of a small steel billet, and belongs to the technical field of steel rolling control. According to the technical scheme, for a descaling temperature difference control model, the key step is to establish an equation (P1-P2) / P1=k delta T x kH (lambda2-lambda1) / lambda2 of the descaling water regulating valve opening, the steel billet heat conducting coefficient, the steel billet thickness and the temperature difference of the upper surface and the lower surface of the steel billet; and for a rolling mill secondflow control model, the key step is to establish the equation omega1 / omega 2=(R2(1+beta1)) / (R1(1+beta2)) of the work roll speed, the work roll radius, and the coefficient of thermal expansion of theupper surface and the lower surface of the steel billet. According to the cascade control method, temperature difference and second flow cascade control are carried out in the descaling stage and therolling stage respectively, so that warping during the rolling process of the small steel billet is avoided or reduced, it is ensured that the rolling process is safe and controllable, and it is guaranteed that the product quality is qualified.

Description

technical field [0001] The invention relates to a cascaded control method for controlling the rolling warpage of small billets, belonging to the technical field of steel rolling control. Background technique [0002] During the billet rolling process, the head or tail of the rolled piece cannot advance straight along the roller table after biting the steel, and may bend upwards, downwards, or even in an uncertain direction, which is called warping. [0003] Analyzing the reasons, one is that after the steel billet comes out of the heating furnace, when it is conveyed on the roller table, due to natural heat dissipation and descaling processes, the temperature of the upper and lower surfaces is uneven, and there is a large temperature difference; the second is that the head and tail of the billet are in the In the rolling process, the distance from the rolling mill is relatively close, and the cooling water of the roll is first contacted, and the temperature drop is more obvi...

AI Technical Summary

Problems solved by technology

[0003] Analyzing the reasons, one is that after the steel billet comes out of the heating furnace, when it is conveyed on the roller table, due to natural heat dissipation and descaling processes, the temperature of the upper and lower surfaces is uneven, and there is a large temperature difference; the second is that the head and tail of the billet are in the In the rolling process, the distance from the rolling mill is relatively close, and the cooling water of the roll is first contacted, and the temperature drop is more obvious. In addition, the head and tail are easier to cool down than the middle part of the billet, resulting in a significantly larger temperature difference between the head and tail and the middle part of the billet; the third is the upper and lower work. There are differences in the diameter or rotation speed of the rollers, resulting in different metal second flow rates on different surfaces of the billet during the nibbling process.

[0004] When the warping of billet rolling is obvious, it will scrape against the guide and conveying roller table, and if it is serious, it will collide with the water cooling pipeline and testing equipment of the roll, and even cause accidents such as drilling the roller table, hitting the roll, and flying

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