Image Recognition Of Pressure Equipment Butt Weldings Using Ultrasonic Phased Array Inspection

The butt weld of pressure equipment quality is critical importance to the safety ofindustrial production.Combining with focused beam and array probe movement,Ultrasonic phased array imaging detection technology can get powerful testinginformation.It has been widely used in the butt weld detection of pressure equipment,but the scan image of ultrasonic phased array detection still need some recognitionskills.Its detect image is different from the black and white stripes of TOFD and theconventional A-scan pulse echo signals. The defects properties in welds, localizationand quantification is determined through the ultrasonic phased array image features,which is key to the promotion and development of new technology, which has importantresearch significance.With the combination of numerical simulation and practical test method, theresearch of ultrasonic phased array inspection map analysis and recognition methodtowards butt weld was carried out in this article.First, this paper explains the laws ofultrasonic phased array transmits and receive beam control, phase delay as well as theimaging principle of phased array. Based on the acoustic field radiation of array probe,and analysis the phased-array focus algorithms, we establish a model of the law of onedimensional array probe focus. Further analysis the application scope of the two scanmodes electronic linear and sector scan., we finally choose the sector scan as the maindetection method in the defect map analysis of the butt weld steel plate.Secondly, using CIVA software to simulate ultrasonic phased array inspection inbutt weld steel plate. According to the Esbeamtool to study the probe setting way ofphased array beam coverage detection area.Taking advantage of CIVA, steel buttwelding model was established and probe setting parameter was setup. Five kinds offlaws including porosity, crack, incomplete fusion, slag inclusion, and lack ofpenetration were simulation and detected in the corresponding parts of steel buttwelding. The scan characteristic of different types of flaws was also summarized whenusing ultrasonic phased array technology. It is known that the law of depth andorientation has certain influence on the result of ultrasonic phased array technology. Atthe same time, a large number of typical defect atlas were obtained which is contrastedto the results of X-ray.Using numerical tests results as a guide,considering ASTM E2700standard on the laboratory testing research, the process scheme of ultrasonic phased array technologyapplied to steel butt welding is set out based on Phascan, a portable ultrasonic phasedarray device. The parameters calibration method of sound speed, delay time, sensitivityand time control gain (TCG) of the testing instrument and probe combination was given.Through the recognition of the defection geometry size of phased array sector scan map,the artificial crack and vertical hole defects of different depth and dip angle wasdesigned and customized. The affection of crack and vertical hole length, width andinclination to phased array results was analyzed.On this basis, a butt weld was detectedand analyzed,which is a group of60pieces including porosity,slag inclusion,incompletepenetration, incomplete fusion and typical defects.For porosity, the sector scan image isa shining round or oval,and diffraction echo displayed with a porosity;For slag inclusion,the image shape was irregular, edge was not clear and the position of diffraction imagefollowed could’t be confirmed due to the unfixed shape; For crack, when there is acertain angle between the sound wave propagation direction and the crack, thediffraction echo image in the up and down crack tip was clarity which can measure thegeometry size and angle of the crack because of the diffraction effects on the crack.; Forincomplete penetration, due to the high echo wave in the middle position, the middleimage brightness was high, two sides edges were not smooth,the image brightness wasclear with significant contrast;Incomplete fusion is similar to incomplete penetration,the high echo wave leaded to the large central area and high brightness of the scanimage.Using phased array testing, the sector scan image of butt weld detects is easy toevaluate.Comparing with the conventional A-scan pulse wave signals, defect signals andgeometry images are easy to distinguish. The phased array sector scan image withdetection arrangement of acoustic wave propagation path is an effective method toanalyze the weld phased array altas. Especially when using the secondary wave detect,the actual position and appearance character of the image is needed to identified. Theresearch work has certain reference value to promote the development of ultrasonicphased array technology and standard establishment in our country.