Comparison and Analysis of Detection Method for Pipe Weld in High Temperature and High Pressure of Supercritical Unit

Lots of micro-cracks were found in pipe butt welds in high temperature and high pressure of supercritical units. They should be tested by various detection methods because conventional ultrasonic testing was difficult in precise measurements of micro-cracks and in monitoring them. By analyzing the operating principle and contrasting the advantages and disadvantages between the three detection methods of ultrasonic, TOFD and phased array, and then the detection results of the three methods by practical application were contrasted. By empirical verification and considering the actual demands of the power plant, TOFD and phased array should be added to detect the special defect area.