CTOD Testing of HAZ and Analysis of Pop-In Behavior

Abstract

HAZ CTOD tests were carried out on nonmatching bead on plate SAW weldments at room temperature. The effects of the notch position and weld metal matching on the HAZ toughness were studied by taking weld metals with three strength levels (austenitic, ferritic and martensitic weld metals). The notches were located parallel (L-type) and perpendicular (T-type) to the straight fusion line and across the beveled fusion line (cross-bond type). The results indicate the T-type CTOD specimens may be used for screening the most brittle zone of the HAZ and may to a certain extent ease the experimental difficulties of the HAZ CTOD testing. The CTOD crack initiation (pop-in) values are controlled by the microstructure of the crack tip zone and the strength of the adjacent material. The recently proposed pop-in assessment procedure was used for the evaluation of the pop-ins and results were discussed in terms of the measurements of the load drop, crack extension and the CTODjump values.