Abstract
The estimation of the size of the model defects and the artificial weld defects by the ultrasonic angle beam testing is studied and the results obtained are summarized as follows, (1) As for the maximum resultant echoes reflected from the model defects, there is a difference of 15 dB between the upper and the lower range of the test results (see, Fig. -5). This is resulted from only the difference of the angle of inclination of the model defect to the surface of the test specimen. (2) As for the test results of the artificial defects, there is no relation between the defect length and the maximum resultant echo (see, Fig. -6), but there is a slight correlation between the defect height and the maximum resultant echo although the deviation of the test results is up to 14d (see, Fig. -7). (3) The results of the ultrasonic testing show considerable difference when tested from one side and from the other side of the weld bead even if the other test conditions remain the same (see, Table-3). (4) As for the estimation of the defect height the method of 6 dB attenuation is better than the method of the maximum resultant echo. (5) The method of 8-9 dB attenuation is applicable for the estimation of the length of the model defect, but 10 dB attenuation is preferable for the artificial defect since the shape of the tip of the defect is uncertain. (6) As for the defects of small size, attenuation methods are apt to overestimate the size of the defects.
