Automatic Ultrasonic Flaw Detector Used In Tube-to-Tubesheet Weld Of Heat Exchangers

The special automatic ultrasonic flaw detector used in tube-to-tubesheet weld of heat exchanger is presented in the paper integrating the traditional ultrasonic flaw testing technology with mechanical , electric and computer technology .The principle of detector is that the A-Scan flaw instrument of USL32 beams the ultrasonic to detect the weld with the method of pulse echo once. The special scanning device to fix the probe is designed .The scanning device scans the weld and samples the echo with the A/D card on the control of computer. After scanning ,the data of echo is processed and the C-Scan graph of weld is displayed. The size and the position of the flaw can be concluded from the graph. The operator can judge the quality of the weld and maintaining the weld .The scanning device ,the computer control of stepping motor ,the data process of ultrasonic echo etc. are designed and researched thoroughly. The request of operator is taken into account on the design of scanning device and software .Here are the main work and conclusions:1) The scanning device is designed and it is light and easy to operate.2)The driving circuit is selected. The cutting-wave circuit used in the driving device is very reliable.3)The aided communicating circuit between the driving circuit and computer is designed .The circuit includes the controller ,the processing circuit of echo ,etc..4)The method of data processing from A-Scan to C-Scan is presented and applied the detector.5)The software is developed.The project comes from the request of engineering .The whole detector is developed based on the request of user. The detector is easy to operate and the detecting efficiency and the rate is high.. The detector is improved gradually and its function is verified. The operation of the detector is expatiated in the end.