ULTRASONIC MEASUREMENT OF WELD PENETRATION

Abstract

The automatic production of high-quality welded joints requires a means of measuring weld quality in real time and a feedback method for regulating that quality. Penetration is a good indicator of weld integrity, and a technique of using ultrasonic pulse-echo measurements to determine weld pool dimensions is discussed. It is concluded that despite the distortion in the ultrasound reflection due to the thermal gradients produced by welding, it is possible to predict the reflection patterns from hemispheres formed by weld pools sufficiently accurately to enable accurate radius measurements to be made, and that this represents an initial step towards realisation of real time weld pool cross section measurement for in-process control purposes.