The principle of ultrasonic flaw detection

Ultrasonic flaw detection is a method that can penetrate into the depths of the metal material by ultrasonic, and when it from a cross-section into another section, the edge of the interface characteristics of reflection will check the parts of a defect, when the ultrasonic beam from the part surface by the probe to meet with defects and the metal element at the bottom, a reflected wave occurs respectively, and it will generate waves and the formation of pulse waveform on the screen, according to the pulse waveform, we can judge the position of the detects and the size of the detects.When the ultrasonic wave encounters discontinuity, it will produce reflection. The reflected ultrasonic wave causes the piezoelectric wafer to vibrate and then generates voltage on both ends of the piezoelectric wafer. The most important thing is how to convert the electric pulse into the waveform of the flaw detector screen, The simulator is displayed through a picture tube. The image of the picture tube is the electron hits the fluorescent substance, causes the fluorescent substance to shine; The electron passes through an electric field to change the direction, hits the screen the different position, causes the screen to reveal the picture. The voltage in the x-direction of the kinescope is the voltage applied by the flaw detector to the piezoelectric ceramics, and the voltage in the y-direction is the voltage generated by the vibration of the piezoelectric ceramics thus forming the waveform on the screen.