================================================================================= Name: Micromagnetic Sensor Dataset for Non-Destructive Characterization of Residual Stress and Hardness in Hard-Turned 51CrV4 Steel ----------------------------------------------- Authors: Felix Wittich, Andreas Kroll University of Kassel Faculty of Mechanical Engineering Institute for System Analytics and Control Measurement and Control Research Group Marcel Krochmal, Alexander Liehr, Artjom Bolender, Sebastian Degener, Thomas Niendorf University of Kassel Faculty of Mechanical Engineering Institute of Materials Engineering Metallic Materials ================================================================================= Abstract: This data set contains measurement data from a micromagnetic (MM) sensor that allows for non-destructive, in-process material characterization of the mechanical properties of ferromagnetic components. It contains the raw sensor signals and 82 features that were extracted from these signals as input variables and corresponding reference measurements of the residual stress and hardness as corresponding outputs. The data set contains two subsets: data set 1 (DS1) with 60 data points and data set 2 (DS2) with 81 data points. ================================================================================= 1. Experimental Setup The parts that were measured 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. 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 (DS1 and DS2) and the maximum compressive residual stress (only DS2). These values where extracted from the residual stress depth profiles. For DS1, 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 (for further details see [1]). For DS2, tangential surface residual stresses were determined with a 2-circle diffractometer equipped with a Cr-Kα-X-ray source. On the primary side, a pinhole collimator with a nominal diameter of 1 mm was used. On the secondary side of the beam path, a Fe-Kα₂ correction slit was used in front of the scintillation counter. Using the sin²ψ-Method with the diffraction elastic constant 1/2 S2 = 6.09 * 10-6 mm²/N, residual stresses were determined at the {211} lattice plane using a 2θ-range of 148°-164° with a step size of 0.1° and a counting time of 0.5 s across 11 ψ-angles ranging from -45° to 45°. Post process Vickers hardness testing was carried out using a Struers DuraScan-70 system with a load of 294.2 N (HV30) for both data sets. ================================================================================= 2. Structure of the data ----------------------------------------------- 2.1 Structure of the h5.-File The h5.-Files are structured as follows: / [Root] └── {Probe_ID} (e.g., A01, A02... for DS1 and 020211, 020222, ... for DS2) ├── References │ ├── ES1 (Surface Residual Stress) │ ├── ES2 (maximum compressive residual stress, only DS2) │ └── HV (Surface Hardness) ├── H16 (Magnetization Amplitude: 16) │ ├── Features │ └── Curves └── H30 (Magnetization Amplitude: 30) ├── Features └── Curves ----------------------------------------------- 2.1.1 Curves This contains the sensor signals as time series. Barkhausen Noise (Bark_H, Bark_M): Bark_H: Magnetic Field Strength in A/cm Bark_M: Barkhausen noise in V Incremental Permeability (Perm_H, Perm_ux, Perm_uy): Perm_H: Magnetic Field Strength in A/cm Perm_ux: Incremental permeability in x-direction in V Perm_uy: Incremental permeability in y-direction in V Harmonic analysis of the magnetic tangential field strength: Harm_M: Measured magnetic field Strength in A/cm Harm_F: Fundamental of measured magnetic field strength in A/cm Harm_H: Sum of harmonics of magnetic field strength in A/cm ----------------------------------------------- 2.1.2 Features 41 features (see Table 1) were extracted from the measurement curves. 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. 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 | ----------------------------------------------- 2.1.3 References The Category "References" contains the corresponding reference measurements for the residual stress and hardness: ES1: Surface Residual Stress in MPa ES2: Maximum compressive residual stress (only DS2) in MPa HV: Surface Hardness in HV30 ================================================================================= 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.