The Research For The Techniques And Equepment Of Auto_Ultrasonic Testing (auto_UT) To The Flaws In The Weld Joint

Ultrasonic inspection of weld has entered the stage of automatic testing and computer-aided flaw identification with the rapid development of techniques in electronics computer, signal processing etc. The topic of this paper is"the research for the techniques and equepment of auto_Ultrasonic testing (auto_UT) to the flaws in the weld joinf'which comes from the project of former ministry of machinery industry on auto_UT inspections with multi-channel to the nuclear container in order to develop on advanced techniques and prototype equepment of auto_UT both for military use for civil use in the future.The focused probes presented in the paper can produce focusing ultrasonic beem whth 6 mm dia.or smaller over 100mm of weld thickness. The diffractive ultrasonic transducers produced the exta-narrow pulses only 0.3~0.5μs in time domain. The transducers presented above can provide the measuring techniques for sizing the flaws quantitatively in weldment. The full automatic ultrasonic testing prototype apparatus HAUT-1 and improved one UT ROBOT-1 are both belong to 4 channels ultrasonic inspection system of weld joint. It consists mailnly of hardwares and softwares such as a scanner with 4 magnet attractive wheels, an ultrasonic emtting and receiving electried circuit board, a high speed sampling board made from fast analog to digital converter(A/D), seam tracking system, controlling computer installed variety of programs like real time control for the scanner, realtime display for thd A-scan, imaging for in flaws projected the images in three dimensions and inspection report editor etc. It is also described and analyzed to the measurement of flaw height with diffraction wave method (TOFD)and how to display its images.Finally, the testing results are demonstrated on a test sample with diameter 1600mm thickness 45mm and a boiler drum with dia. 1800mm, thickness 100mm in Harbin Boiler Works. Both are made of carbon structure steel with weld seams on them respectively and welded by automatic narrow gap welding procedure. The results obtained show that HAUT-1 apparatus has quite well per-formances in the accuracy and the reproducibility of inspection and the imaging processing for thd flaws. Also, the imeging software for sizing the flaw height with diffractive ultrasoinc transducer has been proven through the measurements on the samples with diffrent sizes and depths of artificial slots and put into productive examinetionstage already.