Using the Barkhausen-noise analysis and metal-magnetic-memory method for material characteristics under fatigue damage

Abstract

The article deals with process monitoring and the subsequent diagnosis of fatigue damage during material testing of steel S355. The study was performed by means of the metal-magnetic-memory method, Barkhausen-noise analysis and X-ray diffraction. This combination could significantly enhance the inspection quality of critical mechanical-unit parts during their lifespan. X-ray diffraction was applied for the description of the state of residual stresses, in combination with the Barkhausen-noise analysis, which allows us to immediately determine the changes in the surface layer resulting from the residual-stress redistribution, hardness and potential microcracks. Additionally, a new unconventional method for the determination of the stress-concentration-zone location and for the detection of material defects and imperfections, the so-called metal-magnetic-memory method, will be introduced. Keywords: Barkhausen noise, metal-magnetic-memory method, X-ray diffraction, fatigue damagê lanek obravnava proces kontrole, in iz tega naknadno diagnozo utrujenostne po{kodbe, med preizkusom materiala, jekla S355.[tudija je bila izvedena s pomo~jo metode magnetnega spomina kovine, z Barkhausnovo analizo hrupa in z rentgensko difrakcijo. Ta kombinacija lahko ob~utno izbolj{a kvaliteto kontrole kriti~nih mehanskih komponent med njihovo`ivljenjsko dobo. Rentgenska difrakcija je bila uporabljena za opis stanja zaostalih napetosti, v kombinaciji z analizo Barkhausnovega hrupa, kar omogo~a takoj{nje dolo~anje sprememb v povr{inski plasti, kar je posledica prerazporeditve zaostalih napetosti, trdote in potencialnih mikrorazpok. Dodatno bo predstavljena nova neobi~ajna metoda za dolo~anje podro~ij koncentriranja napetosti ter za odkrivanje napak in nepravilnosti, imenovana metoda magnetnega spomina kovine. Klju~ne besede: Barkhausnov hrup, metoda magnetnega spomina kovin, rentgenska difrakcija, utrujenostna po{kodba