| 摘要 |
PROBLEM TO BE SOLVED: To detect the presence or absence of a mortar lining layer simply from the outer surface of a pipe. SOLUTION: By filling a cast-iron pipe 1 formed with a mortar lining layer 8 therein with fresh water 9 while bringing a probe 4 of an ultrasonic flaw detector into contact with an exterior of the cast-iron pipe 1, the waveform of an echo wave from the opposite surface of the cast-iron pipe 1 is observed. And, when a small peak 11 is immediately behind a large peak 10 of the echo wave appearing at a constant time interval (t), the mortar lining layer 8 is determined to be absent in the portion brought into contact with the probe 4. |
