Issue 78

M. Bronovets et alii, Frattura ed Integrità Strutturale, 78 (2026) 367-377; DOI: 10.3221/IGF-ESIS.78.21

(A) (B) Figure 8: Surface topography of steel disks after tribological tests under conditions of boundary friction before (A) and after (B) LSP treatment. Based on extensive literature data for LSP-treated bearing steels [21, 24, 25], the increased wear resistance is hypothesized to be provided by the formation of a gradient structure of the surface layer and an increase in microhardness. Laser shock treatment is known to result in the formation of a hardened surface layer, which has increased resistance to plastic deformation and abrasive interaction. In addition, the increased surface hardness and compressive residual stresses prevent direct plastic contact between metal surfaces, reducing the coefficient of friction and wear intensity. Thus, the results of the tribological tests demonstrate that laser shock treatment is an effective method for increasing the wear resistance of steel disks. LSP not only reduces the intensity of wear but also changes its character towards milder abrasive and fatigue wear, promoting the creation of a gradient structure within the surface layer. These factors together provide a significant improvement in the tribological characteristics of the materials under study and allow us to recommend the use of LSP to increase the reliability and durability of parts operating under conditions of friction and wear. 2. A detailed study of the surface topography revealed a fundamental change in the wear mechanism after LSP. The untreated samples exhibited substantial wear, manifesting as deep scratches, burrs, and considerable material loss. In contrast, the samples subjected to LSP exhibited a milder wear pattern, accompanied by reduced plastic deformation and material loss. This change is due to the modification of the microstructure of the surface layer and an increase in its strength, which reduces the possibility of plastic deformation and adhesion. B C ONCLUSIONS ased on the tribological studies of AISI 440-C (Russian equivalent 95 Х 18 Ш ) disks processed using laser shock treatment, the following conclusions can be drawn: 1. The findings presented in this study offer substantial evidence supporting the efficacy of LSP as a method for enhancing the tribological characteristics of bearing steels. Surface profilogram analysis, roughness data analysis, and wear pattern and intensity assessment demonstrate significant improvements in both non-lubricated surface friction and boundary friction conditions. LSP led to a change in the wear mechanism, which in turn reduces wear. These results confirm the feasibility of using this method to improve the reliability and durability of bearing assemblies.

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