| 摘要 |
PURPOSE:To detect easily and exactly a welding defect by converting a welding defect of a corner part of T-joint, etc. provided with a backing strip, executing an inspection by using a surface wave-probe method altering to an angle beam- probe method. CONSTITUTION:A probe 1 to be used is a wide band surface wave probe whose frequency is 2MHz, placed on the lower face of a beam 2, and an ultrasonic pulse is transmitted toward a welding part 5. As a result, a surface wave M generated from the probe 1 is propagated along the surface under the beam, passes through a gap to a backing strip 4, and reflected from a corner part 6 of a defect first. Also, the surface wave M propagated toward a welding part 5 from the corner part 6 is reflected from a defect tip part 7. They are displayed as a reflected wave F1 from the corner part 6 and a reflected wave F2 from the defect tip part 7, respectively, in a receiving waveform figure shown on an oscilloscope. Accordingly, it will do that an existence of the reflected wave F1 from the corner part 6 of the defect is discriminated. |
