Creep crack growth in a 1 percent CrMoV steel and a 32 percent Ni 20 percent Cr alloy

For two high-temperature materials, the creep crack growth behaviour has been determined in twenty-five laboratories within a European Group on Fracture (EGF) Round Robin on "Measurement of Crack Growth under High Temperature Conditions". It is shown that the most satisfactory correlations of creep crack growth rates are achieved with the creep fracture mechanics parameter C *. Little influence of specimen shape and size is observed and it is demonstrated that the specimen deformation and cracking behaviour occurs under plane-stress condtions.