Recently developed open-source software based on standard test and normalization methods simplifies the process of generating J-integral versus crack-growth resistance (J-R) curves to evaluate fracture toughness in the ductile region.

Ductile fracture toughness testing is useful for evaluating a material’s structural integrity. This article briefly reviews three widely used J-integral vs. crack growth resistance (J-R) curve test methods for metals: elastic unloading compliance, normalization, and direct current potential drop. The J-Integral calculation is the same in all three methods, with differences primarily involving crack size measurements.

This article identifies several factors that are not fully addressed in most fracture toughness test standards and explains how they may influence calculated values obtained from ferritic steels. Of particular consequence are test temperatures within the ductile-to-brittle transition regime and test specimen geometries when measuring the toughness of weld metal and heat-affected zones.

This article describes how shielding gas composition, either argon or nitrogen, affects the hardness, tensile strength, and toughness of high-power, high-brightness laser welds made on various base materials, including A508 forging steel, 316L stainless steel, Inconel 690, and solution-annealed IN718.