A Procedure Qualification Study on ISO Phased Array Ultrasonic Testing (PAUT) for API 2W 60 Piping Weld

다국어 초록 (Multilingual Abstract)

Objective: This study was conducted for the purpose of verifying the reliability of the inspection results when performing non-destructive inspection of API 2W 60 pipe welds according to the ISO standard PAUT procedure. Background: Radiography Test (RT) of welds has problems in terms of safety for the human body and limitations in the detection capability of plane defects. To supplement this, the PAUT test, which can acquire the test result data file, is used by replacing the film, which is the test record of RT. However, most of the studies on PAUT have been conducted based on the American Society of Mechanical Engineers (ASME) or American Society of Welding (AWS) codes. However, recent customer specifications require international ISO standards. Therefore, specific experimental analysis for the ISO standard PAUT procedure certification of the pipe welding part is absolutely necessary. Method: API 2W60 pipe calibration test specimen and ISO PAUT procedure accreditation test specimen were prepared with reference to previous studies on PAUT theory, research trends, and reliability analysis model of non-destructive testing. The acoustic anisotropy of TMCP steel and the transverse wave velocity of ultrasonic waves were measured using the calibration specimen. Next, the RT and PAUT volumetric non-destructive testing experiments were performed using the test specimens for approval, and the PAUT reliability was verified by comparative analysis of the measured results. Results: The effect of the acoustic anisotropy in the rolling direction and the direction perpendicular to the rolling direction of API 2W60 material on the change in the refraction angle of the ultrasonic beam and the speed of the transverse wave was confirmed. The reliability of PAUT inspection was secured by comparative analysis of RT and PAUT results related to the acceptance of ISO PAUT procedures for pipe welds. Conclusion: The acoustic anisotropy of API 2W60 material was confirmed by decreasing the measured refraction angle in the rolling direction and increasing the measured refraction angle in the transverse direction. In addition, as a result of a comparative verification experiment on RT and PAUT for pipe welds, the reliability of the PAUT result was high, so the verification of the ISO PAUT procedure was confirmed. Application: The contents and results of this study are expected to be utilized as an example of the application of ultrasonic inspection (UT) of welds of acoustic anisotropic materials. Furthermore, it is expected to be used in various ways for accreditation of ISO PAUT procedures for pipe welds.