Fatigue Crack Growth in Multi-pass Butt-welded Joints of Mild Steel

Fatigue crack growth rate properties obtained by testing multi-pass butt-welded joints in the through-the-thickness direction are presented along with a characterization of the mild steel base material. Edge-notched four-point-bending specimens are used to investigate R-ratio, specimen geometry and post-weld heat-treatment effects on fatigue crack growth rates. The pervasive influence of residual stresses on welded joint fatigue testing using the fracture mechanics approach is also discussed. For these multi-pass joints, conservative fatigue crack growth rates are obtained with post-weld heat-treated specimens.