The forming quality of large wind turbine main shaft bearing inner rings directly determines the service life and operational reliability of wind energy equipment. Yet the plastic deformation mechanism and stress–strain evolution of GCr15SiMn bearing inner rings during asymmetric cross-section radial–axial rolling remain poorly understood. Stress–strain curves from isothermal hot compression tests were used to build a three-dimensional finite element (FE) model of inner ring radial–axial rolling, validated by dedicated rolling experiments. The effects of drive roll rotational speed, initial rolling temperature, and radial–axial feed speeds on the stress and strain fields were systematically investigated. Results show that material flow velocity on the outer surface of the radial deformation zone is 100–200 mm/s higher than on the inner surface. The velocity difference between the upper and lower end faces in the axial deformation zone stays below 100 mm/s, confirming synchronous end-face forming. Peak equivalent stress reaches 81.5 MPa in the radial rolling stage and 75.6 MPa in the axial rolling stage. Standard deviation of stress (SDS) and plastic strain (SDP) quantify field uniformity; the most uniform distributions occur at 3.5 rad/s (SDS = 15.09) and 1100 °C (SDP = 4.18). These findings provide a theoretical basis for rolling process optimization and precision forming quality control of asymmetric cross-section wind turbine bearing inner rings.

Wind turbine main bearing rings with non-standard cross-sections are large, and a single rolling operation can hardly satisfy the simultaneous requirements of stress uniformity and dimensional accuracy; how the as-rolled state is inherited by the subsequent hot bulging remains unclear. A coupled thermo-mechanical model of the rolling-bulging sequence of a GCr15SiMn ring was therefore established in Abaqus/Explicit, transferring the geometry and the stress, plastic-strain and temperature fields across the two operations. With all bulging parameters fixed, five initial rolling temperatures (1040–1160 °C) were compared. The rolling stage was validated experimentally, the relative errors of the predicted outer diameter, inner diameter and wall thickness being below 0.37%, 0.28% and 2.5%, respectively, and the mesh-convergence deviation below 2%. Bulging reduced the mean stress by 21.9–35.6% and preserved the as-rolled uniformity ranking, the lowest stress standard deviation (3.46 MPa) occurring at 1130 °C. The outer- and inner-diameter roundness errors decreased from 6.29–7.61 and 4.13–5.14 mm to 1.05–1.44 and 0.80–1.35 mm, corresponding to correction ratios of 81–83% and 74–81%; the retained fractions stayed within 17–19% and 19–26% of the as-rolled error, so bulging scales the inherited shape error rather than equalising it. Considering dimensional accuracy and the stress state together, 1130 °C is recommended as the optimum, with 1100–1130 °C as the preferred process window. The bulging results are simulation predictions pending full-size experiments.

Q420 high-strength steel exhibits pronounced anisotropy due to its rolling process, and conventional uniaxial tensile testing is incapable of acquiring strain field evolution information during the local necking stage. In this study, quasi-static uniaxial tensile tests were conducted on Q420 cold-rolled high-strength steel sheets at six orientations (0°, 15°, 30°, 45°, 60°, and 90°) using Digital Image Correlation (DIC) technology. The evolution of the strain field and the corresponding stress–strain responses at different orientations were systematically investigated. The results show that the DIC technique effectively captured the full-field strain evolution of the specimens from uniform deformation to local necking and final fracture in all directions. Taking the 0° direction as an example, the local maximum engineering strain prior to fracture reached 35.866%, whereas the average fracture strain within the gauge section was only approximately 22.5%, corresponding to a ratio of approximately 1.6 and clearly demonstrating the severe strain concentration within the necking zone. The stress–strain curves corresponding to different rolling directions exhibited pronounced anisotropy. The tensile strength was highest in the 90° direction and lowest in the 0° direction; however, the 0° direction exhibited the best ductility, whereas the 45° direction showed the poorest ductility. Among the six orientations, the midpoint transverse engineering strain exhibited the largest absolute value in the 45° direction, further indicating that this orientation is the most susceptible to plastic instability. In this work, DIC-based full-field measurement was combined with multi-directional tensile testing to quantitatively characterize the relationship between local strain concentration and anisotropy. The findings provide high-precision experimental data for the calibration of anisotropic constitutive models and the optimization of forming processes.

Accurate modeling of ore materials is fundamental to high-precision simulations in mineral processing and remains a key research focus. To address the modeling challenges arising from the inherent heterogeneity and strength diversity of ores, this study proposes a novel method based on the bonded particle model (BPM) in the Discrete Element Method (DEM), incorporating multi-sized sub-particle stochastic generation and assembly, as well as bond strength parameter design. The method was applied to model and simulate impact crushing of 30 mm size fraction gold, iron, and copper ores with varying strengths. The resulting particle size distributions of fragmented ores were analyzed. Furthermore, drop weight tests were conducted on ore samples of the same size fraction, and the experimental mass distribution of fragmented particles demonstrated good consistency with simulation results. These findings validate the capability of the proposed method to effectively characterize the strength diversity of natural ores, offering an advanced approach for high-fidelity modeling of mineral materials.