INSPECTION METHOD FOR PERIPHERAL WELD ZONE

PROBLEM TO BE SOLVED: To provide an inspection method that makes it possible to determine whether inner surface beads in all peripheral weld zones have normal sizes.SOLUTION: The inspection method according to the present invention comprises: a preparation step of preparing a reference pipe P2 having the same outer diameter or inner diameter with that of a pipe P to be examined, fitting a first ring member 7 having a thickness meeting a determination criterion to an inner surface of the reference pipe, and generating a first reference image as an X-ray image of the reference pipe using an X-ray inspection machine; an inspection step of generating an inspection image as an X-ray image of the pipe P1 to be examined; and a determination step of determining whether a peripheral weld zone of the pipe to be examined is normal using the first reference image and inspection image. In the determination step, the inspection image is compared with the first reference image and it is determined that inner surface beads have normal sizes at the peripheral weld zone when the radial position of a pixel region corresponding to a top part of the inner surface beads at the peripheral weld zone in the inspection image is at the same position with or radially outside a radial position of a pixel region corresponding to an inner surface of the first ring member in the first reference image, and it is determined that the beads have defective sizes when radially inside.SELECTED DRAWING: Figure 5 【課題】周溶接部の内面ビードの寸法の良否を全数判定可能な検査方法を提供する。【解決手段】本発明に係る検査方法は、被検査管Ｐと外径及び内径が同じ基準管Ｐ２を用意し、基判定基準に応じた肉厚を有する第１リング部材７を基準管の内面に取り付け、Ｘ線検査機を用いて基準管のＸ線画像である第１基準画像を生成する準備工程と、被検査管Ｐ１のＸ線画像である検査画像を生成する検査工程と、第１基準画像及び検査画像を用いて、被検査管の周溶接部の良否を判定する判定工程とを含む。判定工程において、検査画像及び第１基準画像を比較した場合に、検査画像中の周溶接部の内面ビードの頂部に相当する画素領域の径方向位置が、第１基準画像中の第１リング部材の内面に相当する画素領域の径方向位置と同一又は径方向外側であれば、周溶接部は内面ビードの寸法が良好であると判定し、径方向内側であれば不良であると判定する。【選択図】図５