Acoustic Emission Study of Fatigue Crack Propagation of Weld Joint for X52 Pipeline Steel

Abstract

The crack propagation of different weld joint samples were detected by acoustic emission (AE) technique. The samples were from the basic metal, weld seam and heat affected zone (HAZ), The results showed that the crack growth rate of basic metal was higher than weld seam and HAZ because of the transverse compressive residual stress in joint. But the coarse of grains was the reason for higher rate of weld seam than that of HAZ. And AE waveforms of crack propagation from three microstructures were different. The most compositions of AE signals were higher frequency of 300KHz for weld seam and lower one of 100KHz for basic metal and HAZ.