The remanence of a ferromagnet is formed under the influence of many factors, the main of which are a magnetic field (DC and AC), temperature, mechanical stress, and chemical transfor mations. Remanences obtained by different ways are differently resistant to external influences. Remanence observed in structural elements may result from one factor or from all of the above. It is shown that the use of remanence as a parameter for assessing the stress strain state, i. e. the "method of magnetic memory", without taking into account the conditions of the formation of the remanence state in a product area under testing will have low assessment reliability.