Ultrasonic testing system for ERW mill

In-line ultrasonic testing systems inspect welding defects in the welded zone (seam) in ERW (electric resistance welded steel tubes and pipe) mill for mill control and quality assurance. Owing to the expansion of the field of application of ERW pipe to include high-toughness and high-strength line pipes and higher grade oil country tubular goods, it became necessary to increase the stringency of the quality control system of the ERW mill. To meet this need, new in-line ultrasonic testing systems have been developed for ERW mills in Wakayama Steel Works of Sumitomo Metal Industries, Ltd. As a result, the new systems can detect defects in the mid-call portion which can not be found by conventional methods, and the new systems can reliably detect defects so that the accuracy rate of defect inspection has been doubled and the rejection rate has been significantly reduced