Analysis for Defects of Base Material near Girth Weld of a Pipeline
In view of suspected porosity problem in the base material of Φ406.4 mm×7.9 mm SSAW pipe near girth of L360M steel found on a pipeline construction site,types and causes of defects were analyzed by means of ultrasonic detection,DR Ray detection and metallography inspection,and how to detect such defects by ultrasonic non-destructive testing technology was discussed.Results show that the defect of pipe end is dense porosity,which are caused by repair welding of base metal after steel pipe leaves factory,and reasons are not thoroughly cleaned before the repair welding,the welding rod is not dried or welding pool is not properly protected.Phased array ultrasonic technology has more advantages in detecting small defects in pipes.