Introduction

Abstract

Defect sizing nondestructively using ultrasonics is a very complex task. In the daily routine of ultrasonic operators, defect sizing is done by comparison of the echo amplitude of a natural defect to the amplitude generated by an artificial defect at the same distance from the transducer as the natural defect. The artificial defects used are not the same globally. In parts of the world, influenced by the USA, side-drilled holes are used while under European influence flat-bottomed holes are preferred. Both procedures are described in standards and codes. When side-drilled holes are used, a distance amplitude correction curve is recorded. For flat-bottomed holes, the so-called distance–gain–size method is applied.