Method and apparatus for adjusting defect gate in ultrasonic pulse-echo testing

摘要

The present invention refers to a method of ultrasonic testing a workpiece by the pulse-echo technique and an apparatus therefor. An initial portion of a workpiece to be tested is conveyed past an array of electroacoustic transducer probes. The transit time through the workpiece of the transmitted ultrasonic signals from each probe comprising the array is measured. The maximum measured transit time is stored. Subsequently as a slightly shifted second portion of the workpiece is conveyed past this array of transducers, the transit time through the workpiece of ultrasonic signals transmitted by each probe of the array is again measured. The stored value is updated responsive to the latter obtained values. The final updated value is conducted to a flaw detector circuit for terminating a defect gate used in conjunction with testing the workpiece for defects by the pulse-echo test method.