Application of instrumented impact test for studying dynamic fracture property of 9Cr-1Mo-V-Nb-N steel

Dynamic fracture toughness property of 9Cr-1Mo-V-Nb-N heat-resistant steel was studied over a broad range of temperatures from -196 to 650 degrees C, Results show that reasonable dynamic fracture toughness values of 9Cr-1Mo-V -Nb-N steel can be obtained from instrumented impact test of precracked Cha rpy specimens, according to the assumption that crack initiation occurs at a load equal to (P-m + P-y)/2. Fractographic observation shows, close corre spondence exists between P-D oscilloscope traces and fracture morphology, t hus P-D traces can be used to analyse the fracture process of 9Cr-1Mo-V-Nb- N steel. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.