A method for adjusting roll gap of slab continuous caster under unsteady pouring condition

Abstract

The invention relates to an adjusting method of a slab caster roll gap under the unsteady state pouring condition, and belongs to the technical field of the continuous casting production technology. Firstly, a safety roll gap, a static roll gap and the roll gap changing rate is set, and a target roll gap obtained before casting is a safety roll gap value; at the pouring and tail blank throwing stage, target roll gap values are set according to different blank throwing lengths and different tail blank lengths; when the difference between the set roll gap value and the target roll gap value exceeds + / -0.1 mm, the set roll gap value is changed to the target roll gap value with the roll gap changing rate; when the difference between the actual rolling reduction and the target rolling reduction exceeds + / -0.1 mm, the actual rolling reduction is changed to the target rolling reduction with the roll gap changing rate; and a PLC system executes the set roll gap value, and the difference between the actual roll gap value and the set roll gap value is within + / -0.1 mm through feedback adjustment of a displacement sensor. The durable and stable transition of the actual roll gap and equipment loads is guaranteed, degradation or waste caused by the poor center quality of a casting blank at the unsteady state stage is reduced, and blank lagging accidents are avoided.

Description

technical field [0001] The invention relates to a method for adjusting the roll gap of a slab continuous casting machine under unsteady pouring conditions, belonging to the technical field of continuous casting production technology. Background technique [0002] The dynamic soft reduction technology has been widely used in most slab continuous casting machines in China. The dynamic soft reduction is to calculate the solidification end of the slab through the heat transfer model, and to change the roll gap of the fan section within a certain range of solid phase ratio. A certain amount of reduction is applied to the slab, on the one hand to eliminate the porosity caused by solidification shrinkage, and on the other hand to promote the diffusion and redistribution of high-concentration solutes, so as to achieve the purpose of improving central porosity and central segregation. [0003] In order to ensure the stable quality of slabs, the constant drawing rate of the continuous...

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Problems solved by technology

[0003] In order to ensure the stable quality of slabs, the constant drawing rate of the continuous casting machine and the unsteady pouring ratio have become important issues in production. Various reasons such as early warning and equipment failure make the pouring process in an unsteady state. At this time, in order to ensure the stability of production and the quality of the slab, it is necessary to change the roll gap operation. Accidents such as stagnant slabs and poor internal quality of slabs

[0004] The traditional dynamic soft reduction roll gap control scheme is based on setting the basic roll gap, subtracting the total target reduction calculated by light reduction before subtracting this position is the actual target roll gap, and the sector section control system directly executes the target roll gap ;In the process of starting and stopping casting, the roll gap did not avoid the process of billet head and billet tail. If there is a deviation in the roll gap value or model calculation deviation, the ratio of steel reforming in the billet head and billet tail area is high due to the poor internal quality of the billet, and it is very easy to cause Slab accident; and when the dynamic light reduction position or reduction amount changes during the unsteady pouring process, the actual roll gap has a large instantaneous change, resulting in excessive instantaneous strain of the slab and increased resistance to casting. It is very easy to cause quality problems such as cracks in the middle of the slab in the unsteady state, severe center segregation and looseness, or production accidents of the slab

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