Herausforderungen bei der bruchmechanischen Prüfung von oxiddispersionsverfestigten (ODS)-Cr-Stählen

Different oriented 0.25T- and 0.16T-C(T) specimens of hot rolled- and hot extruded 14Cr ODS steel were tested within the temperature range from 20°C to 700°C. Elastic-plastic fracture toughness values were estimated according to ASTM E1820 15 on J-∆a curves measured by the unloading compliance method. The rolled plate of 13Cr ODS had higher fracture toughness in L-T than in T-L orientation. The rolled ODS shows secondary cracks which were more pronounced for the L-T oriented C(T) specimens than for T-L orientation. The secondary cracks strongly influence the propagation of the main crack. The fracture toughness of the hot extruded 14 Cr ODS also strongly depend on the specimen orientation.