Energy Diagnostics - is a Physical Basis of the Metal Magnetic Memory Method

摘要

The basic diagnostic parameter of the MMM method is the gradient of magnetic leakage field or this field's variation intensity factor at the local stress concentration zone (SCZ). It was established that this very diagnostic parameter, due to the magnetomechanical effect, directly reflects the energy state of surface and depth layers of the metal in SCZs. The laboratory investigations on specimens under the conditions of static and cyclic loading resulted in obtaining of the energy ration between magnetic parameters (magnetic leakage field and its gradient) and mechanical parameters (σ_y and σ_l). Using that energy ratio it is possible to perform a practical assessment of metal components' lifetime in SCZs based on the measured factors and the actual non-failure operating time of a unit in question on the date of inspection. The report considers examples of the practical application of energy ratio in diagnostics and resource evaluation using the MMM method.