| 摘要 |
PURPOSE:To permit flaw detection of defects such as cracks generated in a piping despite the presence of penetration beads and ruggedness on the inside surface of the piping by bringing two pieces of probes having the same radius of curvature of the contact parts as that of the outside circumference of the piping into contact with the outside circumference of the piping. CONSTITUTION:With a straight line which intersects with the ultrasonic beam direction X1 of an ordinary probe 3 at an angle beta and passes through the incident point P1 after working as a symmetrical axis, said probe is worked to the curvature of a radius R. Such probes 3 are disposed symmetrically on the right and left on a piping 1 with the axial line as a center, and one of these is used as an oscillator and the other as a receiver. The probes 3 are scanned in such a way that the mutual position relations in the axial line direction and circumferential direction of the piping 1 do not deviate, whereby flaw detection is accomplished. The advancing direction of the ultrasonic wave beam 5 of this case is in the direction parallel to the axial line direction of the piping 1. Hence, despite the presence of a penetration bead near the crack 2' on the inside circumferential surface of the piping, only the crack 2' is detected accurately without detecting this. |
