Unstable fracture phenomenon of welded joints with weld residual stresses

Abstract

Residual stress variations were determined through small- and large-scale specimen welds using neutron diffraction to evaluate the effect of residual stress on the brittle crack propagation path. The results revealed that significant tensile stresses accelerated brittle crack propagation, while compressive stresses obstructed the brittle crack propagation path. The evaluations were performed using small scale specimens, such as CT specimens. To assess the brittle crack propagation arrest toughness, tests with full-scale specimens were performed. The objective was to clarify the mechanism of brittle crack propagation arrest in welds and to establish the basic theory of a welding technique that uses compressive residual stress to prevent brittle fracture.