Prediction of the Mechanical Properties of P91 Steel by Means of Magneto-acoustic Emission and Acoustic Birefringence

Abstract

The paper describes an application of nondestructive volumetric magnetic and ultrasonic techniques for evaluation of the selected mechanical parameter variations of P91 steel having direct influence on its suitability for further use in critical components used in power plants. Two different types of deformation processes were carried out. First, a series of the P91 steel specimens was subjected to creep and second, one to plastic deformation in order to achieve the material with an increasing strain level up to 10%. Subsequently, non-destructive and destructive tests were performed. Magnetic methods based on measurements of magnetoacoustic emission and magnetic hysteresis loop changes as well as the ultrasonic method based on acoustic birefringence measurements, were applied. Finally, the static tensile tests were carried out in order to evaluate the mechanical parameters. It is shown that some relationships between the selected parameters coming from the non-destructive and destructive tests may be formulated.

Use of Time-Frequency Representation of Magnetic Barkhausen Noise for Evaluation of Easy Magnetization Axis of Grain-Oriented Steel

“…Those changes in the magnetic flux can be observed by a coil located at the surface of the material, in the form of voltage noise induced in its turn as a result of rapid changes in the degree of magnetization [ 4 ]. This method is used for various industrial applications for non-destructive condition testing and quality assessment of ferromagnetic materials, e.g., for evaluation of residual stress, active tensile and compressive stress, microstructure and micro hardening [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In addition to the possible applications mentioned above, the MBN is also used to evaluate the directional properties of ferromagnetic materials.…”

The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels

“…Naturally one has to take into account the fact that the curves are reversed, since the positive plastic deformation results in negative compressive stresses and vice versa. As for the central peak, in this region the overall BE intensity decreases for both deformation modes (even though the amplitudes behave in a J Nondestruct Eval (2017) 36 :10 different way) due the dislocation structure modificationthe changes in that region may be material dependent due to the differences in the dislocation structure of their initial state [4][5][6][7]. For the higher deformation levels the dislocation structure modification becomes less significant and being so the sigmoidal curve can be treated as a curve obtained for the material with high dislocation density subjected to elastic stress.…”

“…Such attempts have been made yet, as it turned out, the observed dependence of the BE signal intensity on the deformation level is strongly material dependent-for the tensile deformation it can increase [4] for soft materials, such as e.g. Armco iron, decrease [5] for high strength martensitic steels, or behave in a nonmonotonic way [6,7] for the intermediate materials. Being so the assessment of the deformation level sometimes requires application of rather advanced signal analysis techniques.…”

Damage development of Inconel 718 due to laboratory simulated creep

“…In that way, the maximum value of the acoustic birefringence increase along the gauge length ∆B max could be determined. The measurements were taken by means of a 5 MHz shear wave piezoelectric transducer coupled to the specimen surface by a viscous epoxy couplant (Makowska et al, 2017). The distribution of ultrasonic measurement points on the specimen is schematically presented in Fig.…”