AUT of Weld Zones of the Girth Welds in the CRA Composite Subsea Pipeline

The inner surface of the CRA composite subsea pipe is always overlaid by 3 mm stainless steel. RT is the normal inspection method of the girth weld. Due to the low efficiency and high risk of RT, the CRA pipe-laying efficiency will pull down. This essay makes a research of the AUT technique focusing on performing the evaluation test on the 22 defective welds (242 induced defects located in different area) by the combination of the low frequency LW PA probes, creep probes, TRL probes and TOFD probes, so as to evaluate the POD of individual area in the CRA girth weld.