Study On The Inspection Of Weld Defects Of Old In-service Pipes By Ultrasonic

The development of pipeline transportation and energy industries, particularly oil and gas industry development are closely related, especially after World War II pipeline industry has been booming. Old pipeline in service in China at10,000km, of which the main building of70years, mainly in China’s northeast and southwest. Was due to metallurgical, pipe, construction site welding, testing and other capacity constraints, there are a lot of pipe weld defects, weld pipe failure incidents are very prominent. Through the old pipe weld defects statistics and analysis, we found a common weld defects such type of weld cracks, pores, slag, lack of fusion, incomplete penetration, pout, and the wrong side of such defects, and a variety of defects complex interaction of defects in welds.In this paper, the ultrasonic testing of weld defects of the old pipeline adaptive research and Research selected instruments used by the commonly used weld inspection method comparison analysis, the ultrasound has a fast, easy, free space, environmental impact advantage, determine the choice of ultrasonic testing, the old pipeline weld defects detection and assessment. Type of pipe weld defects and the identification and analysis of different types of artificial defects to complete special test block custom, customized special test probe; final weld defects were qualitative and quantitative dimensions research, including qualitative analysis of weld defect detection technology, welding quantitative characterization of defects in sewing technology research. Come to the old pipeline for specific technology ultrasonic testing of weld defects, and defects in qualitative and quantitative evaluation methods.Artificial defect detection through final test and physical anatomy of the testing methods and testing to verify the conclusions, arrive at the weld quantitative detection technology, the old pipeline in service can quantitative detection of the weld, the depth of defect detection error is less than lmm, can detect and distinguish the smallest defect depth of0.5mm. And the old oil pipeline in the northeast and the Daqing oil pipeline for the actual test application, test result is good.