Surface layer state after hard turning of 51CrV4

Description of the dataset:<br><br>Hard-turning experiments were conducted on cylindrical specimens made of a quenched and tempered (Q&amp;T) steel 51CrV4<br>in different initial surface hardness levels, i. e. 400 HV30, 500 HV30 and 600 HV30. Prior to heat treatment,<br>all specimens were manufactured with the same roughness requirements in order to ensure an almost identical surface <br>finish before hard-turning. Three different sections of nine specimen of each hardness level<br>(i.e. in total 27 section-specific areas per hardness level) were machined with varied cutting parameters feed rate<br>(f), depth of cut (a_p) and cutting speed (v_c).<br>Hard-turning of the specimens was carried out on a servo-conventional lathe of type Weiler C30 using<br>polycrystalline boron nitride (PCBN) inserts with a corner radius of 0.8 mm.<br><br>After hard-turning, residual stress depth profiles were determined using X-ray diffraction (XRD),<br>respectively for each specific area of a specimen. Residual stress measurements were conducted using a<br>Pulstec μ-X360 diffractometer equipped with a 0.3 mm collimator and CrKα-radiation with an exposure time<br>of 120 sec. Depth profiles were determined by successive removal of the material surface layer using<br>electro-chemical polishing. The obtained data have been evaluated applying the cos α-method without consideration<br>of any mathematical stress correction.<br><br>Post process surface roughness in axial direction was determined using a Mitutoyo SJ-210 tactile roughness<br>measuring device. Post process Vickers hardness testing was carried out using a Struers DuraScan-70 system<br>employing a load of 294.2 N (HV30).<br>For more detailed information on the material and the experimental setup, i.e., chemical composition, specimen<br>geometry, machines and parameters used for hard-turning operations and post process measurements, the reader is<br>referred to [1].<br><br>A full factorial experiment design was used with two levels for the initial hardness levels H_Vinit and three<br>factors for the cutting parameters, f: {0.05 mm, 0.25 mm, 0.5 mm}, v_c: {100 m/min, 175 m/min, 250 m/min},<br>a_p: {0.05 mm, 0.25 mm, 0.5 mm}, resulting in 81 different combinations. For the residual stress depth profile<br>modeling, measurements for 12 different depths are available:<br>{0, 10, 20, 30, 40, 50, 60, 80, 100, 120, 150, 200} μm, providing for N = 972 samples in total.<br><br>Two data sets are provided:<br>1. "hardness_roughness_hard_turning.csv" with the 81 data points for the surface hardness and roughness measurements.<br>2. "residual_stress_profile_hard_turning.csv" with the 972 data points for the tangential residual stress depth profiles.<br><br>[1]     Thomas Wegener, Alexander Liehr, Artjom Bolender, Sebastian Degener, Felix Wittich, Andreas Kroll, &amp; Thomas Niendorf,<br>        "Calibration and validation of micromagnetic data for non-destructive analysis of near-surface properties<br>        after hard turning" in HTM Journal of Heat Treatment and Materials, 2022, 77(2), 156-172.