Issue << content << Estimation of the residual strength of AISI304 steel under static and cyclic loading using coercive force measurements


DOI: 10.12737/article_599d8ff3494061.31411838

2017. Vol.20. 3, pp. 39–45

Estimation of the residual strength of AISI304 steel under static and cyclic loading using coercive force measurements

A. P. Gopkalo, G. Ya. Bezlyudko, V. A. Nekhotiashchiy

The obtained results are based on the data from static and cyclic tensile testing of laboratory specimens as well as of sign-variable cyclic deformation. The coercimeter sensor with 4 mm of length (distance between the inside edges of magnetic pole pieces) with 1 mm depth of magnetization allows one to investigate the distribution of coercive forces along the length of the specimen test portion at tension and sign-variable cyclic deformation and build the Нс kinetics within specimen surface local zones. Under conditions of tension or sign-variable cyclic deformation in most damaged zones of the laboratory specimens there is an increase of the coercive force values up to the moment of metal discontinuity, whereupon its values decrease. Using the variation of kinetics of coercive force the staging of damage accumulation process at tension and sign-variable cyclic deformation is established. Being aware of the kinetics of Нс at ascending or descending curve sections it is possible to evaluate the residual metal strength. The possibility of use of structurescope for the detection of the most deformed zones with the determination of principal stresses direction and of metal discontinuities as pores and fatigue cracks is shown. The subsurface cracks are found to be detected. The distribution data of the amount of ferromagnetic phase (α-Fe) along the laboratory specimens test portions under conditions of tension or sign-variable cyclic deformation are given.

Keywords: structurescope, specimen test portion, coercive force, strain, fatigue cracks, damage.
 
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