The fatigue of metals is a relatively new part of mechanics of destruction. In modern theories to explain the destruction of a material of fatigue is considered that the process begins and flow the basis of generation and accumulation of micro-cracking in the material. To describe this process is by using kinetic diagrams of fatigue. The interest to the theory is a discussion of the process of fatigue of middle level. This article examined the kinetic diagrams of fatigue of middle level and evaluate their parameters by ultrasound measurements.