Research on Phased Array Ultrasonic Technique for Testing Tube to Tube-Sheet Welds of Heat Exchanger

The tube to tube-sheet weld is the main connection structure of heat exchanger. This paper presents the phased array ultrasonic technique for testing the tube to tube-sheet welds of heat exchanger. The optimization analysis of phased array parameters and the simulation on the acoustic field with CIVA software were completed. The mentioned phased array parameters included array elements, array element size, deflection angle, ultrasonic frequency and so on. An ultrasonic testing system was designed and fabricated in accordance with the structure of heat exchange tube and fillet welds position. The ultrasonic C-scan was carried out by the ultrasonic testing system with its circumferential scanning by a mechanical scanning device while the axial electronic linear scanning by the phased array probe. At last, tests on samples with the porosity and incomplete fusion flaws were performed by the ultrasonic testing system. Experimental results showed that the phased array ultrasonic technique could effectively detect the porosity flaws and the incomplete fusion flaws in the tube to tube-sheet welds of heat exchanger.