| 摘要 |
PURPOSE:To take a high-precision measurement without depending upon the set gain and sensitivity of a flaw detector by estimating the sectional size of a defect part on the basis of the propagation time of an ultrasonic wave. CONSTITUTION:A transducer 1 for ultrasonic wave transmission and transducers 2 and 3 for reception are arranged at specific intervals and scanned along an object 4 to be measured while contacting the surface 4a of the object 4. Then, the difference DELTAl between the lengths ABC and ADE of ultrasonic wave propagation paths extending to the transducers 2 and 3 from the transducer 1 through the defect part 5 is a function of the depth L of the defect part 5 and the radius (r) of the section of the defect part and varies with scanning distance. Then, the relation between the difference DELTAl and scanning distance is calculated geometrically by using the depth L and radius (r) as parameters and the calculated difference is compared with an actually measured difference DELTAl to estimate the radius (r) of the section of the defect part. |
