Research On Application Of X-Ray Thickness Gauge In Steel Rolling

As a basic industry iron and steel industry occupies an important position in the national economy, in which rolled sheet strip is an indispensable part of the metallurgical industry production. At the same time when measuring quality steel plate thickness is one of the most stringent and most obvious indicator, only accurately measure the thickness can provide precise parameters for the plate thickness measurement and control systems, which laid an important position of thickness gauge in steel rolling production, affecting accuracy and production efficiency.Measurement with ray thickness gauge for its stability, high measurement accuracy and many other features, it’s widely used in industrial online thickness measurement, in which x-ray measured thickness gauge compared to isotope thickness gauge with better security, high measuring precision and noise, etc., in recent years has been more and more used in steel rolling field, and gradually occupy the market.The main research topics include hardware circuit design and improve the stability of the algorithm for establishing fitted model to improve the measuring accuracy of the measurement.Firstly, the software to solve the calibration curve of X ray and the design of the model fitted the data, in order to improve the accuracy of sheet and strip thickness measurements is proposed an improved type of double exponential model based on differential evolutionary algorithm to fit the data, and combined with the polynomial fitting algorithm, reducing the relative error of the measurement.Secondly, the hardware design of high voltage power supply circuit, using a novel phase-shift Zero Voltage Switching PWM converter to achieve soft switching, combined with bi-directional voltage double rectifier technology designed 70KV adjustable constant voltage constant current high voltage power supply, AC current control unsaturated filament current reaches the constant, extends the life of the X-ray tube, bi-fold pressure, pressure to reduce the voltage level.Finally, the unit has been designed to fit the thickness of the various parts have been described, and mainly composed of circuit design, the better the data fit to the data processing is completed, the next crew to use STM32F4 chip(Cortex-M4 core), because of its outstanding data processing and computing ability, can be better to complete the signal acquisition and processing, and finally realize the algorithm.The system has completed the design and manufacture of the physical prototype,0-4mm steel has been measured in the laboratory conditions. In the 0-1mm range, measurement accuracy reached 0.001mm, reaction time is better than 5ms, fully meet the measuring requirements of steel rolling field.