Research And Application Of Round Bloom Continuous Casting Of Mold Level Control System

In the production of round billet continuous casting, mold steel level is required to maintain stability. On the one hand, it can avoid to protection slag to get into the steel,and it effects the billet quality. On the other hand, it conduces to the formation of billet shell and avoids the steel water to leak and overflow. So the mold level control system plays a crucial role in the metallurgy continuous casting mold.The core of mold level control system is stopper control. Switch stopper controls the flow of molten steel from tundish to molds. Because of the mold level’s time-varying and nonlinear, the slag and other impurities in the process of the production are easy to adhere to the surface of the stopper. And it affects the normal flow of molten steel and increases the difficulty of control. As a result, the basic PID control can’t be achieved using effect.In order to ensure the effect of the mold level control, the paper combines the project of Lai Wu Steel Corporation(LSC) 800 mm round billet Continuous Casting Machine(CCM), and analyzes the factors of influencing control realization. At the same time, some difficulty about affecting the mold level control is researched deeply and we find some solution of influencing control realization. At the beginning of the cast, some factors are changing, and control becomes difficult. So automatic adjustment can’t execute directly. During the continuous cast, the change of factors decrease instantly, and the condition is formed. In order to the effect of mold level’s automatic adjustment, control stage can be divided into cast starting and normal casting. First, cast starting is full of the steel water in the mold by subsection control complete, and using PID keeps the mold level stability. Because of the slag’s adhering, it reduces the control area of the stopper and is bad of the control’s effect. The paper analyzes, designs and develops the stopper washing system. It ensures clean on the surface of the stopper and improves the control effect. Second, in the normal casting, the paper improves the basic PID. At the same time, the paper also analyzes and designs the cascade PID control. It is adopted to realize stopper control. The primary loop of mold level adjustment and the deputy loop to regulate stopper improve the precision of adjustment to ensure the effect of control.In the hardware design, the paper carefully considers the equipment’s reliability and stability. And then the paper selects the hardware according to the work’s environment in order that the system can work normally under atrocious conditions. In the software design, the redundancy technology ensures that the system can work normally without control and keeps the stability of the system. In the network design, the communication system design mixes with optical fiber and cable. It reduces signal disturbance and ensures the accuracy of the automatic adjustment.After the completion of the mold level control system research, it is debugged and used in the continuous casting machine of different reconstruction project in LSC. Compared with the old control system, this system improves the degree level of automation, and achieves higher control precision. So it has obtained the good effect.