Research On Control Method Of Slag Thickness Of Automatic Crystallizer

In the continuous casting process,it is necessary to cast protecting slag on the surface of the molten steel in the mold continuously.And the quality of the slag casting directly affects the quality of the slab.Therefore,The automatic slagging machine of protecting slag which can achieve uniform slagging and slagging on demand is designed to improve the slagging quality of protecting slag.(1)The rectangular compensation mechanism is designed to make the central movement track of the spiral feed pipe outlet of the crystallizer automatic slag adding machine as a straight line to reduce the waste of protecting slag;the side inclined discharge outlet with an inclined angle of 3 degrees is designed to make automatic distribution of protecting slag during conveying,and the weight deviation of the protecting slag in each region of the crystallizer is less than 2g.The protecting slag is uniformly distributed along the longitudinal direction of the crystallizer.(2)The control method of the slag thickness open loop is proposed due to the kinematics analysis of the mechanism of the automatic slag adding machine of the crystallizer.Under the condition that the rotating speed of the conveying motor is constant,the swinging motor is controlled to make the speed of the center of the spiral outlet consistently during the swinging process.Finally,the experiment verifies that the maximum displacement of the sliding platform is less than 2mm,and the maximum is not more than 5%,which indicate that the slag thickness open loop control can achieve uniform slag addition.(3)In the continuous casting process,due to the continuous consumption of the protecting slag,the thickness of the protecting slag at each position in the crystallizer is not uniform.so the closed-loop control method of the slag thickness is proposed,that is controlling the center speed of the discharge port of the spiral feed pipe and the laser distance measuring sensor continuously detects the thickness of the protecting slag in each area of the crystallizer.And then adjust the rotational speed of the conveying motor by the difference value between the average value of the detected thickness and the thickness required by the continuous casting process.Finally,the rationality of the slag thickness closed-loop control method of the mold automatic slag adding machine is verified by experiments.The maximum error of the Crystallizer slag thickness is 3mm,which achieve uniform slagging and slagging on demand.