ULTRASONIC FLAW DETECTION APPARATUS

摘要

PURPOSE:To detect a flaw with high reliability by reducing a flaw undetected region by calculating the distance up to the corner part of an oblique angle probe by utilizing the beam distance up to the bottom surface of a material to be inspected due to the ultrasonic beam of an oblique probe. CONSTITUTION:A beam distance operation circuit 11 uses the distance X up to the bottom surface of a material 1 to be inspected measured by the vertical probe 2a present at the almost same position as an oblique angle probe 2n and the distance S from the probes 2a, 2n to the side surface of the material 1 to be inspected is used to calculate the distance Y up to the corner part to which the beam from the oblique angle probe 2n goes. When the position of a bottom surface echo B moves to a position B' by some cause, since a flaw detection gate FG changes like FG' according to the moving quantity, the position of the flaw detection gate FG is controlled according to the fluctuation of the distance Y up to the corner part so as to follow a member 9 to prevent the generation of a flaw undetected region or the erroneous detection of the bottom surface echo.