METHOD OF MEASURING DEPTH OF SURFACE OPENING DEFECTS OF A SOLID MATERIAL BY USING ULTRASONIC WAVES.

摘要

The depth of surface opening defects of a solid material is determined by utilising chiefly ultrasonic waves. Ultrasonic waves are permitted to fall on the surface opening defects while being scanned with a probe back and forth and a threshold value of a predetermined level is set onto an echo envelope that is formed by the echoes of ultrasonic waves reflected depending upon the moving positions of the probe from the surface opening defects. The region that exceeds the threshold value is integrated for a range in which the probe has moved in the region and the depth of the surface opening defects is measured with the area value of the region calculated by integration as an evaluation index. this makes it possible to measure the depth of cracks in the welded portion or the depth of surface opening defects such as cracks of the member caused by fatigue in a portion where the stress concentrates.