Improving the wear resistance of 440 C bearing steel balls through mechanical ball milling induced gradient structure
X. C. Xie, Zhihui Liu, Zhuan Zhao
Abstract
This study explored 440 C steel ball wear resistance via mechanical ball milling with Al 2 O 3 powder. We used a customized grinding jar to compare heat-treated, untreated, Al 2 O 3 -treated, and Al 2 O 3 + distilled water-treated samples. We assessed wear resistance, residual stress, microhardness , and surface roughness. Results revealed that the combination of distilled water and Al 2 O 3 powder induced nanostructured stacking faults, increased dislocation density , and grain refinement. Treated samples had a > 200 µm thick strengthened layer, − 355 MPa residual stress, and max microhardness of 776.6 HV. These samples showed superior wear resistance, reduced wear volume, and lower friction. This suggests that Al 2 O 3 powder and distilled water in mechanical ball milling enhance ball mechanical part wear resistance, offering industrial potential.