METHOD OF ACOUSTIC EMISSION CONTROL OF QUALITY OF ANNULAR WELD DURING MULTIPASS WELDING Russian patent published in 2020 - IPC G01N29/14 

FIELD: defectoscopy.

SUBSTANCE: use: for acoustic-emission quality control of annular weld. Summary of invention consists in the fact that broadband converters are installed along the seam contour, calibration of the monitoring object is performed, setting of selection thresholds above the noise level and reception of acoustic signals occurring in the welding zone and their amplification, filtering signals based on a given amplitude, analogue-to-digital conversion, recording time of arrival of acoustic emission signals to acoustic transducers, calculating coordinates of sources of acoustic signals, wherein deflection grid is constructed after calibration along weld seam contour, threshold values of normalized coefficient by total amplitude are set, then, during each welding pass, recording acoustic emission signals and calculating their total amplitude to calculate coordinates of active areas of weld and normalized coefficient K^{i, j} in each defective grid cell, comparing them with threshold values and when the first threshold value is exceeded, the defect is considered to be insignificant, when the second threshold of the normalized coefficients is exceeded, the defect is considered to be significant, then acoustic emission signals are recorded during weld seam cooling and normalized coefficients K^{i, j} are calculated by amplitude and compared with their threshold value for weld seam cooling stage, after that, comparing obtained data, coordinates of location of sources of acoustic signals of welded seam are corrected.

EFFECT: high reliability of location of defects in annular welded seams and shorter processing time of inspection results.

1 cl, 1 tbl, 3 dwg