Utilization of Hollow Notched Rounds in Fracture Toughness Evaluation

摘要

Results of an experimental program to determine fracture toughness data utilizing small notched round tensile specimens are presented. Hydrogen embrittlement was utilized as a crack starter for several solid A1S1 4340 steel specimens. The fractured areas were examined to differentiate the slow crack growth due to hydrogen and the final rapid catastrophic fracture. Hollow notched round specimens of A1S1 4340 steel, Aluminum 7075-T651 and gun steel 4330 were tested to failure for various outside diameter, notch root radius and internal hole size. The resulting apparent fracture toughness values are compared to known values obtained from precracked specimens. (Author)