Study On Rapid Detection Method Of High Temperature Scum Thickness During Casting Of Aluminum Ingot

During the pouring process of aluminum ingots,a large amount of slag will be generated on the surface of the aluminum liquid flowing into the casting mold,and its main component is solid Al₂O₃,if the slag is not cleaned up in time,it will lead to the production of aluminum ingots containing too much impurities and affect the quality.At present,when the industrial robot is used to fish slag,there is no detection of the specific thickness of the slag,and the slag shovel descends according to the preset fixed value to fish slag,so there is a problem of unclean fishing slag,in order to make the industrial robot more effective in fishing slag,it is necessary to study the method of rapid detection of the thickness of aluminum slag.The aluminum liquid above700℃flows into the aluminum ingot casting mold and is quickly transported to the dross picking station via conveyor belt,so it is necessary to finish the dross thickness detection before the industrial robot picks up the dross.This study proposes to analyze the surface temperature change of the floating slag to detect the thickest position of the floating slag,and then apply laser ultrasonic detection technology to focus only on the thickest floating slag thickness detection method,in order to achieve the goal of rapid detection of floating slag thickness.This research is carried out mainly from the following aspects:（1）Firstly,the Comsol software is used for finite element simulation of aluminum surface slag to analyze the law of surface temperature change with time for different thickness of slag,and the analysis shows that:the thicker the position of aluminum slag,the faster its surface temperature decreases,that is,as long as the temperature measurement equipment is used to measure the lowest point of the surface temperature of slag,the thickest position of aluminum slag can be derived.（2）Then laser ultrasonic detection technology is used to detect the thickness of the thickest measured floating slag,and for the reflection characteristics of the ultrasonic longitudinal signal of the aluminum floating slag,the two-wave hybrid interferometer method is used to detect the ultrasonic longitudinal wave.In order to make the technique more effective for thickness detection,Comsol software is used for finite element simulation to analyze the influence of the simulation parameters on the calculation results,and analyze the influence of the laser excitation characteristics parameters on the ultrasonic waveform obtained by excitation,and obtain better parameters by orthogonal test method,and finally use the envelope algorithm based on segmental power function interpolation method for thickness calculation.The feasibility of laser ultrasonic inspection for thickness detection of floating slag is verified.（3）Based on the ultrasonic signal obtained from laser excitation,the Matlab software is used to superimpose Gaussian white noise on the original signal considering the actual working environment,and the effects of different noise reduction methods are compared and analyzed,mainly wavelet noise reduction method,wavelet packet noise reduction method and empirical mode decomposition（EMD）noise reduction method are analyzed,and it is concluded that the combination of wavelet packet noise reduction and empirical mode decomposition noise reduction is better for the noise containing signal.（4）Finally,the overall inspection system was constructed based on the rapid detection method of aluminum liquid surface scum obtained from the above study.Based on the data analyzed in the study,the equipment in the inspection system is selected and the operation flow of each device in the inspection system is analyzed.