A Study Of Improve The Defect Detection Rate For Oil And Gas Transmission Spiral Submerged Arc Welded Pipe

Spiral submerged arc welded steel pipe (SSAW) is one of the common oil and gaspipelines. With the starting of China’s West-East Gas Pipeline Project, Researchers haveovercomed many diiffculties in the spiral submerged arc welded pipe production process.However, In the actual production of the pipe, the device configuration is not balanced，technology is outdated, As a result，pipes always have some defects, Cracks, Lack ofpenetration, Lack of fusion, these defects directly reduces the cross-section of the weld.Therefore, these defects are typical hazardous defects. In this paper, researching spiralsubmerged arc welded pipe common defects, using Pulse reflection method and Time of FlightDiffraction to improve the defect detection rate.First, carired out an investigation on SSAW pipe detection situation and process，Analyzed the theory of Pulse reflection method and Time of Flight Diffraction, studied thedefect location, quantitative and qualitative. Produced Simulation defects from the SSAW pipe,using Pulse reflection method and Time of Flight Diffraction to measure depth and length ofthese defects, the testing results showed that TOFD detection accuracy than conventionalultrasonic testing for lack of fusion defects. Finally, use the manual detection simulationSSAW automatically detection, discovered that ultrasonic testing have undetectedphenomenon. If the undetected defects in the weld central, TOFD method can be used toconduct the additional tests. TOFD method to Quantitative is well, but it is not suitable to testsurface defects. Combined the both methods to test SSAW pipe defects, it will receive theideal test results.