Ultrasonic Examination for Planar Defects Perpendicular to Examination Surface at or near the Weld Root

When a butt weld is examined by ultrasonic test, it is difficult to detect the defects near weld root, and even more difficult to detect the planar defects which are perpendicular to the examination surface at or near weld root. According to ultrasonic basic principle and the many years′ experience, the authors conclude a method for effectively judging the planar defects at weld root and near weld root. The paper provides a reference for people working in the same field.