Study of the corrosion properties of structural steels using magnetic characteristics

Abstract

Heterogeneities of the crystal structure and chemical composition, as well as the impurity elements forming inclusions cause deviations of the properties of test object from the required physical and mechanical parameters which significantly affects the reliability and service life of the product. We present the results of studying the susceptibility of structural steels to corrosion in aggressive environment using their magnetic characteristics. Structural-phase transformations occurred in steels under the effect of heat treatment change their properties, including magnetic and corrosion ones. Heat-treated 09G2S, St3, 15XSND steel samples were studied. In addition to the main magnetic parameter — coercive force, we also used spectral characteristics of the samples obtained using a remagnetization curve, magnetic hysteresis loop. The multi-parameter approach with harmonic components was used to identify the corrosion rate and coercive force correlation. Determination of the corrosion rate in this case can be reduced to classical problems of technical diagnostics. It is shown that a complex parameter based on harmonic components obtained using a magnetic hysteresis loop and the corrosion rate exhibit a pronounced correlation which provide developing a non-destructive method for predicting the corrosion resistance of structural steels. The results obtained can be used to improve the rapid method for determining the corrosion-hazardous zones of steels using the magnetic parameters.