APPLICATION OF A SEPARATE-COMBINED CHORD TRANSDUCER FOR DETECTION IN THE PIPE WALL OF A REFLECTOR «CYLINDRICAL HOLE» ORIENTED PARALLELLY TO THE PIPE`S AXIS BY MEANS OF ULTRASONIC FLAW DETECTION METHOD

This article discusses the use of a separate-combined chord transducer to detect the reflector «cylindrical hole» drilled in the end wall of a piece of steel pipe parallelly to its axis. This type of reflector simulates extended defects of cylindrical (or close to cylindrical) shape that can occur in the process of rolling pipes. It is shown that the use of a separate-combined chord transducer in the general case does not allow to detect a defect in the wall of the pipe extended parallelly to its axis. This type of transducer can detect only areas of extended defect which are not parallel to the pipe axis, i.e. its initial or final part. But it will be impossible to distinguish the beginning (end) of the extended defect from the local reflector (for example, cracks). By observing the reducing of the bottom signal amplitude from the pipe end can be detected only a small area of the parallel to the pipe axis extended defect in the end wall of the pipe, when placing the transducer over the defect in focal length from the pipe end. Therefore, it is recommended to use in industrial conditions other types of transducers to detect defects extended parallelly to the pipe axis.

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