Fracture toughness of welding procedure qualification and component welds tested in SENB and C-specimens

Standard fracture toughness tests were done using full thickness (60 mm) single edge notched bend (subsidiary test pieces) and compact specimens extracted from identically fabricated longitudinal SA-tandem plate and tube weldments on a C-Mn steel. Critical values of crack tip opening displacement (CTOD) and J-integral were determined at -10 degrees C at the onset of stable crack extension, at instability, and at the first attainment of maximum load for the weldmetal of double V- and K-joints, and for the heat affected zone of K-joints, both in the as-welded and post-weld heat treated condition. For single edge notched bend (SENB) and C-specimens CTOD values were calculated following BS 5762 and the ASTM draft standard for CTOD testing, respectively. The J-integral results were obtained from integrating froce/displacement diagrams. The toughness results for the weldmetal and the heat affected zone of the different welds are compared; influenced of specimen geometry, restraint conditions during welding, and post-weld treatment are discussed. It is shown that CTOD- and J-integral results correlate linearly and that the factor of proportionality does not depend on specimen type and material post treatment, but on different notch locations. (IWM)