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

For two high-temperature materials, the creep crack growth behavior was determined in twenty-five laboratories within the EGF Working Party "Measurement of Crack Growth under High Temperature Conditons". 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 conditions.