Fatigue Crack Growth in Steels 42CrV and IR3Mo

摘要

An automatic fatigue crack growth measurement system has been developed, in which a special four-channel A-D acquisition board that could collect data in phase is used. The data collecting frequency could be in the range of 4× (2～25600)Hz. Therefore the system is suitable for fatigue tests whose frequencies are not higher than 250Hz. Reasonable results were given out with the system according to the results measured by microscope. Eddy current transducers and standard load cell measured the displacement and the load respectively. The function and usefulness of the system were discussed. As an application of the system, the fatigue crack growth rates (FCG) and the thresholds of steels 42CrV and IR3Mo are presented. The system can instantly calculate fatigue crack lengths, stress intensity factors and fatigue crack growth rates. The resistance to FCG of the steel 42CrV in air is higher than that of the steel IR3Mo.