Abstract: The phased array ultrasonic technology is used to detect turbine welded diaphragm. Aiming at the important influence of weld groove angle of steam turbine welding diaphragm on the phase-array ultrasonic unfused defect echo signal, the longitudinal wave sound field of different diameter flat bottom holes in the groove angle range is analyzed by CIVA simulation software. The flat bottom holes with different sizes and inclination angles are designed to verify the simulation results. The simulation and test results show that: (1) With the increase of the angle of the flat bottom hole, the echo amplitude of the flat bottom hole decreases, and the amplitude difference of the flat bottom hole of different sizes becomes smaller. (2) The amplitude of the large flat bottom echo decreases rapidly with the increase of the inclination angle. When the tilt angle is around 7.5°, the echo amplitude in the 2.5 MHz longitudinal sound field is equivalent to the 0°Ф4 mm flat bottom hole echo equivalent. This will result in an increase in the unfused defect and an increase in the amplitude of the echo in the actual detection of the main weld of the outer ring of the se-parator. (3) When setting the longitudinal wave detection sensitivity of the main weld of the outer ring of the diaphragm, it should be compensated according to the groove angle and the probe frequency. It can be compensated by the measured value of the test block or the simulated calculation value. In the defect analysis, the defect cannot be judged only according to the amplitude equivalent.
季昌国, 余超. 汽轮机焊接隔板坡口角度对相控阵超声回波信号影响的定量研究[J]. 材料导报, 2019, 33(Z2): 441-446.
JI Changguo, YU Chao. Study on Influence of Groove Angle of Turbine Welded Diaphragm on EchoSignal by Ultrasonic Phased Array Testing. Materials Reports, 2019, 33(Z2): 441-446.
渝公网安备50019002502923号 版权所有：《材料导报》编辑部
2019, Vol. 33 
