Mechanism Analysis Of Vibrating Crack On The Mill's Pipeline

The iron and steel industry plays an important part in the national economy. The mill, as an important component in the iron and steel industry, affects the quality of the steel plate directly. For many reasons, the mill system suffers from vibration and burst accidents easily, which brings great loss to the company. Thus it is of vital importance to analyze the mechanism of the vibration systematically.To meet the requirement of the Baoshan Iron and Steel Corporation, we take a research on the mechanism of the vibration accidents which happened in the company recently. Since June 2010, several vibration and burst accidents happened to the Baoshan Iron and Steel Corporation and made the mill system shutdown for several times. These accidents all happened in the relatively weak components such as the elbow and the accumulator. The accidents are thought to be caused by the hydraulic components of the mill system, thus in this paper the pipeline before the valve, the pump, the accumulator and the screw down system have be studied, as well as a series of improvement measures been concluded.In chapter 2, the impedance method has been used to deduced the impedance of the pipeline, and the resonance length of the pipeline has been calculated for further design. The comparatively perfect fluid-solid coupling method has been introduced for modeling. The flow pulsation of piston pump and the constrain condition of the bracing position have also been analyzed, which must be taken into consideration when modeling.In chapter 3, the traditional method for parameters setting as well as its deficiency is introduced. Then integrated model-based method for setting the parameters is proposed, which uses approximation method to deal with the pipeline component and uses the genetic method to optimize the parameters. Because the method is based on the model of the whole system, more suitable parameters are hoped to be obtained.In chapter 4, the control strategy as well as components of the screw down mill system has been introduced. Then in chapter 5 Simulink has been used to simulate the system in order to find out the reason to cause the vibration in this part. Finally theoretical explanation of the reason has been given.In chapter 6, the reasons that cause the vibration of the pipeline that is before the valve have been concluded systematically. The suggestions to improve the vibration accidents of Baoshan Iron and Steel Corporation have been given, and the reasons for the measurement have been analyzed.