Fracture toughness testing using non-standard bend specimens - Part II: Experiments and evaluation of T0 reference temperature for a low alloy structural steel

The present study addresses an experimental investigation of the effects of geometry and loading mode on the cleavage fracture behavior of a high strength, low alloy structural steel using standard and non-standard SE(B) specimens, including a non-standard PCVN configuration. Fracture toughness testing conducted on various bend specimen geometries extracted from an A572 Grade 50 steel plate provides the cleavage fracture resistance data in terms of the J-integral at cleavage instability, J(c). The experimental results show a potential effect of specimen geometry and loading mode on J(c)-values which can help mitigating the effects of constraint loss often observed in smaller fracture specimens. An exploratory application to determine the reference temperature, T-0, derived from the Master Curve methodology (which defines the dependence of fracture toughness with temperature for the tested material) also provides additional support for using non-standard bend specimens in routine fracture applications.