PROCEDURE FOR DETECTION OF DEFECTS IN WELD SEAMS AND THEIR LOCATION BY ACOUSTIC SIGNALS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2011 - IPC G01N29/14 

FIELD: machine building.

SUBSTANCE: wide band acoustic converters along weld seam on welded structure receive acoustic signals occurring in weld zone and during cooling. They filter signals by a value of specified peak amplitude, convert them into analogue-digital form, and record time of entries of acoustic emission signals into acoustic converters. There are calculated coordinates of acoustic signal sources, and by results of acoustic emission control there is plotted a pattern of localisation in a zone of welding and cooling. Upon analysis there is assessed quality of weld seam and degree of hazard of revealed defects in it. Also, during signal recording, there is additionally determined an envelope of rising edge of acoustic signals and are set threshold values above a level of noise, but not above maximal value of a fast mode and below maximal value of slow mode. The signals are localised during welding and cooling; there is compared obtained distribution of total emission of signals along the weld seam with theoretical uniform distribution of total emission. There are chosen sections of the weld seam with maximal deviation of experimental distribution of total emission from the theoretical one. On these sections signals are clustered by rate of rise edge between threshold levels. An effect is established when a set critical number of signals in one cluster is exceeded.

EFFECT: reduced time for acoustic emission control of weld seam during welding and cooling facilitating correction of weld defects before weld seam cooling.

2 cl, 3 tbl, 6 dwg