The important status of guide ring in large power plants and its manufacturing methods were introduced.
The advantages of manufacturing methods including welding and electrolysis were discussed. In order to
ensure the brazing quality of the guide ring, ultrasonic nondestructive testing (UNDT) method was used in this
study. According to the features of the defects that may show up during brazing, the feasibility and reliability of
UNDT were proved in theory. Based on the theory, an ultrasonic C-scan imaging test method was developed using
a water immersion focusing probe. According to the features of the inspected images, the defects were segmented
using a morphology image processing based method. The defects can be localized and sized by employing the
algorithm of area reconstruction. At last, the combination ratio of brazing interface can be calculated and the
brazing quality of the guide ring can be evaluated.
GAO Shuang-sheng1 (高双胜), CHI Da-zhao2* (迟大钊), GANG Tie2 (刚铁)
. Ultrasonic Nondestructive Testing and Evaluating System for
the Brazing Quality of a Guide Ring[J]. Journal of Shanghai Jiaotong University(Science), 2012
, 17(5)
: 527
-530
.
DOI: 10.1007/s12204-012-1319-4
[1] Tang Xin, Cao La-mei, Gai Qi-dong, et al. Investment casting technology and heat treatment process of k4169 superalloy integral nozzle ring [J]. Aerospace Materials & Technology, 2007, 37(6): 82-86 (in Chinese).
[2] Tsukada K, Yoshioka M, Kiwa T, et al. A magnetic flux leakage method using a magneto resistive sensor for nondestructive evaluation of spot welds [J]. NDT & E International, 2011, 44(1): 101-105.
[3] Kim K C, Fukubara H, Yamawaki H, et al. The development of simplified ultrasonic CT system and its application to the evaluation of weld metal [J]. Journal of Mechanical Science and Technology, 2001, 15(1):52-60.
[4] Werner H. The passivation current density as a parameter for a non-destructive test on plants of the pitting corrosion resistance of welded NiCrMo alloys [J].Journal of Solid State Electrochemistry, 2006, 10(9): 753-757.
[5] Zapata J, Vilar R, Ruiz R. Automatic inspection system of welding radiographic images based on ann under a regularisation process [J]. Journal of Nondestructive Evaluation, 2012, 31(1): 34-45.
[6] Rathod V R, Anand R S. A comparative study of different segmentation techniques for detection of flaws in nde weld images [J]. Journal of Nondestructive Evaluation,2012, 31(1): 1-16.
[7] Alaknanda, Anand R S, Kumar P. Flaw detection in radiographic weldment images using morphological watershed segmentation technique [J]. NDT & E International, 2009, 42(1): 2-8.
[8] Wang Y, Sun Y, L¨u P, et al. Detection of line weld defects based on multiple thresholds and support vector machine [J]. NDT & E International, 2008, 41(7): 517-524.
[9] Shao J X, Du D, Chang B H, et al. Automatic weld defect detection based on potential defect tracking in real-time radiographic image sequence [J]. NDT & E International, 2012, 46(3): 14-21.
[10] Bazulin E G. Application of the maximum entropy method in ultrasound nondestructive testing for scatterer imaging with allowance for multiple scattering [J]. Acoustical Physics, 2010, 56(1): 96-104.
[11] Fei D, David K H, Warchol M. Simultaneous velocity, thickness and profile imaging by ultrasonic scan [J]. Journal of Nondestructive Evaluation, 2001, 20(3):95-112.
[12] Gao Shuang-sheng, Chi Da-zhao, GANG Tie. Extraction of weak signal for weld defect and its qualification in joint interface between dissimilar materials [J]. Transactions of the China Welding Institution, 2010,31(11): 81-84 (in Chinese).
