Method of ultrasonic flaw detection of pipe

摘要

A method of ultrasonic flaw detection of a pipe comprises comparing ultrasonic waves passing through a test piece portion with the arithmetic means of ultrasonic waves passing through portions adjacent each side of the test portion. The comparison is made around the entire periphery of a pipe, for example, an austenic heat resisting cast steel pipe used as a hydrogen manufacturing reformer tube. This method is free from adverse influence of macrostructures unevenly distributed in the peripheral direction of the pipe, and enables a quantitative grasp of flaws in a base material and a weld of the pipe.