Double wall Double Image Technique for very small pipes to assess the location of defects and Sensitivity in the butt weld of the tube

In this study, hydraulic pipes under ۰.۵ inches (۰.۵ and ۰.۷۵ inches) with ۱.۰۳۰۸ material were inspected and radiographically tested in the steelmaking unit after penetration welding and GTAW welding method. Radiographic examination (X-ray imaging) is one of the approved methods among non-destructive tests to detect internal defects without damaging the tubes. Small cracks and small defects, when the pipes are under pressure or pressure and exposed to a lot of heat, cause serious damage and cause many life and financial accidents. In many cases, the quality of the radiographs is low due to the scattering of X-rays and gamma rays. In order to investigate the defects in lip-to-tube welding with maximum OD size (۰.۵ and ۰.۷۵ inches), the radiographic test was takenusing the double-walled image (DWDI) technique with the least two exposures at right angles. ASTM Hole or ASTM / Din is usually used and maintained to determine the radiographs, and here the size limitation prevented the image quality from being controlled. In many cases, the quality of the radiographs was low due to the scattering of X-rays and gamma rays. Depending on the thickness of the tube and its OD, the radiographic source is placed on the weld with a slope of ۱۲ to ۱۵ degrees to obtain an elliptical image of the weld edge of the tube. The welded tube is rotated at different angles by inserting the signals given by the DWDI technique and radiographed with (source to film distance) defect distance to different films. The defect pattern at different angles of rotation and SFD has been predicted for the study .

کلیدواژه ها:

Radiographic test ، DWDI ، non-destructive testing ، welding ، tube .