Authors: Felix Wittich, Andreas Kroll University of Kassel Faculty of Mechanical Engineering Department of Measurement and Control Thomas Wegener, Alexander Liehr, Artjom Bolender, Sebastian Degener, Thomas Niendorf University of Kassel Faculty of Mechanical Engineering Institute of Materials Engineering Metallic Materials Description of the dataset: This data set contains measurement data from a micromagentic (MM) sensor that allows for non-destructive, in-process material characterization of the mechanical properties of ferromagnetic components. It contains 82 features that were measured using a MM sensor as input variables and corresponding reference measurements of the residual stress and hardness as outputs. The parts that were measured originate from hard turning experiments of quenched and tempered (Q&T) steel 51CrV4 with different initial surface hardness levels, i. e. 400 HV30, 500 HV30 and 600 HV30. For details on the manufacturing process, please refer to https://doi.org/10.48662/daks-69. The MM measurements were carried out using a 3MA-II device from Fraunhofer IZFP. The sensor utilizes four measurement methods: Barkhausen noise, incremental permeability, multi-frequency Eddy current analysis and harmonic analysis of the tangential magnetic field strength, resulting in 41 features (see Table 1) that are extracted from the measurement curves. The data set includes 81 data points with 82 input variables. By using two different magnetization amplitudes (16 A/cm and 30 A/cm), 82 input variables are available. The identifiers consist of the prefix 'R_H16_' or 'R_H30_', indicating the magnetization amplitude used, together with the identifiers from Table 1. As output variables the surface hardness is available and two characteristic values for the near surface residual stress state: the residual stress on the surface, i.e. at depth 0 micrometer and the maximum compressive residual stress. These values where extracted from the residual stress depth profiles. The residual stress was measured with X-ray diffraction, using a Pulstec μ-X360 diffractometer equipped with a 0.3 mm collimator and using CrKα-radiation with an exposure time of 120 sec. Post process Vickers hardness testing was carried out using a Struers DuraScan-70 system with a load of 294.2 N (HV30). The supplied .csv contains 82 columns with features from the MM measurements and 3 columns with the reference measurements: ES1 (surface residual stress), ES2 (maximum compressive residual stress) and HV (surface hardness). The units of the measured quantities are specified in the .csv header. Table 1. Input variables (grouped for the four measurement methods) with identifiers and description. | Variable (Identifier) | Explanation | | --------------------------------------------------------------- | ------------------------------------------------------------------------------------------ | | **Harmonic analysis of the tangential magnetic field strength** | | | Vmag | Final stage voltage of the electromagnet | | A3, A5, A7 | Amplitude of the 3rd, 5th, and 7th harmonics | | P3, P5, P7 | Phase shift of the 3rd, 5th, and 7th harmonics relative to the fundamental wave | | UHS | Sum of all harmonic amplitudes (incl. 3rd, 5th, and 7th) | | K | Distortion factor (measure of distortion) | | Hco | Coercive field strength according to harmonic analysis | | Hro | Harmonic content of the magnetic field strength at zero crossing | | **Barkhausen Noise** | | | Mmax | Maximum noise amplitude | | Mmean | Noise amplitude averaged over one signal period | | Mr | Noise amplitude at the remanence point | | Hcm | Coercive field strength according to Barkhausen noise (field strength at the noise maxima) | | DH25m | Curve broadening at 25% of the curve height | | DH50m | Curve broadening at 50% of the curve height | | DH75m | Curve broadening at 75% of the curve height | | **Incremental permeability** | | | umax | Maximum incremental permeability | | umean | Incremental permeability averaged over one signal period | | ur | Permeability at the remanence point | | Hcu | Coercive field strength according to (field strength at the noise maxima) | | DH25u | Incremental permeability – 25% of the curve height | | DH50u | Incremental permeability – 50% of the curve height | | DH75u | Incremental permeability – 75% of the curve height | | **Multi Frequency Eddy Current** | | | Re1, Re2, Re3, Re4 | Real parts of the working frequencies | | Im1, Im2, Im3, Im4 | Imaginary parts of the working frequencies | | Mag1, Mag2, Mag3, Mag4 | Magnitudes of the working frequencies | | Ph1, Ph2, Ph3, Ph4 | Phases of the working frequencies | For more details on the sensor and the experimental setup, please refer to [1]. [1] Thomas Wegener, Alexander Liehr, Artjom Bolender, Sebastian Degener, Felix Wittich, Andreas Kroll, & Thomas Niendorf, "Calibration and validation of micromagnetic data for non-destructive analysis of near-surface properties after hard turning" in HTM Journal of Heat Treatment and Materials, 2022, 77(2), 156-172.