OBRABOTKAMETALLOV Vol. 27 No. 1 2025 technology á=90° á=75° Fô á=60° Fô á=45° Fô î m î m î m î m FN FN FN F, FN F F F Fig. 2. Change in the normal FN and tangential Fτ components of the interaction force between the tool and the workpiece surface at different tool inclination angles α (ξm – the amplitude of vibrations of the ultrasonic emitter) a b Fig. 3. Traces (1) and cross-sections of traces (2) of the working tool traces on the sample surface: a – at α = 90°; b – at α ≠ 90° Considering the longitudinal nature of the vibrations, to ensure uniform processing of curved surfaces, the tool axis must be directed at a specified angle to any section of the surface being processed. In order to improve the processing quality of surfaces with complex geometries, ultrasonic SPD methods are being improved andmodernized [17, 19]. Methods using multi-element deforming tools [23, 24] have emerged, as well as hybrid methods combining features of smoothing and impact processing [27, 28] or a combination of SPD with thermal [31, 32] and thermochemical processing [29, 30]. In this regard, the aim of this work is to study the influence of the oscillation system’s inclination angle on the surface properties of steel 45 under ultrasonic SPD. To achieve this aim, the following tasks were addressed: ● to analyze the change in microstructure of the specimens processed by ultrasonic SPD; ● to evaluate the changes in microhardness and roughness of the specimens; ● to conduct comparative wear tests on the specimens; ● to propose technological recommendations for the effective application of ultrasonic SPD at various oscillation system’s inclination angles. Research procedure Materials and methods for specimen preparation A hot-rolled bar made of 45 mm structural steel with a diameter of 42 mm was used for experimental studies. Cylindrical specimens, 300 mm in length, were machined from the bar. The chemical composition of the steel was determined by spectral analysis using a Foundry-Master LAB spectrometer (SYNERCON LLC, Moscow, Russia). The composition is shown in Table. Chemical composition of steel 45 (%) Material C Cr Mn Ni Cu W Si Fe Steel 45 0.46 0.09 0.55 0.27 0.1 0.01 0.21 98.31
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