| Welding is one of the essential processes in industry today, Welding plays an importantrole in aspects of aerospace and nautical tanker; and it is widely used in electric andtransportation. All these require a high demand for weld-joint. If it is not good, it will have abad effect on weld and quality, What is worse, it may lead to some serious accidents. So weshould pay much more attention to weld inspection.Austenitic steel is widely used in industrial manufacturing as a material for its corrosionresistance, high temperature resistance, and the non-magnetic characteristics. But the uniqueinternal structure of austenitic steel makes it detection difficult. Thick internal crystalstructure of austenitic steel has a great restrain in ultrasonic, and the phenomenon makesultrasonic scatter easily, and also reduce the signal to noise ratio greatly. As a result, it willlead to inaccurate test.In this paper, the basic theory of phased array detection was described. The theory oftransducer radiated sound field was researched. The plane model of signal sensor in XOZ andYOZ was established. The model of signal sensor in focusing and deflection was simulated.The main parameters of ultrasonic phased array was simulated: The number of arrayelements(N), the width of array elements(a), the distance between array elements(d),deflection angle(θ). According to《NB/T4701416-2011welding procedure qualification forpressure equipment and Welding specification for Pressure Vessel》,《JB/T4730-2005nondestructive testing of pressure equipment》standard, design defects specimen with pores,cracks, no penetration, lack of fusion and slag inclusions. The weld joint simulated detectedby X ray, determine the form of each weld joint. The weld joint simulated with one defectdetected by phased array. |
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