Haruetai Maskong

Excessive surface friction encountered during metal-forming processes typically leads to die wear and seizure in part surfaces, which consequently shortens the die’s service lifespan and lowers the surface quality of the formed parts. To minimize surface friction, tool surface modification is required. This study focuses on reducing the sliding friction of SKH51 high-speed steel by fabricating micro-grooves with various crosshatch angles using a nanosecond pulse laser. The effects of laser texturing parameters on achieving the groove aspect ratio of 0.1 were investigated. This aspect ratio facilitates lubricant retention and enhances lubrication performance on the contact surfaces. The influence of groove crosshatch angles (30°, 60°, and 90°) on the friction in the sliding contact between a textured high-speed steel disc and an AISI304 stainless steel pin was evaluated using a pin-on-disc test with a constant load. Moreover, the contact pressure distribution and stress concentration associated with each groove pattern were numerically analyzed using the finite element method. The results demonstrated that a laser power of 20 W effectively produced groove geometries with the desired aspect ratio. Among the tested patterns, the surface textured with a 60° crosshatch angle exhibited the lowest coefficient of friction of 0.111, compared to 0.148 for the untextured surface. Finite element analysis further revealed that the 60° crosshatch pattern provided the most balanced combination of load redistribution, reduced mean pressure, and average stress, which may reduce the friction under sliding conditions. These findings confirm that laser surface texturing, particularly with an optimized crosshatch angle, can significantly reduce sliding friction and enhance the tribological performance of high-speed steel tools.

Excessive surface friction encountered during metal-forming processes typically leads to the wear of die, and seizure in part surfaces which consequently shortens the die’s service lifespan and lowers the surface’s quality of the formed parts. To minimize surface friction, the tool surface modification is required. This study focuses on reduction of the sliding friction of SKH51 high-speed steel by fabricating micro-grooves with various crosshatch angles using a nanosecond pulse laser. The effect of laser texturing parameters to achieve the groove aspect ratio of 0.1 were investigated. This aspect ratio facilitates lubricant retention and enhances lubrication performance at the contact surfaces. The influence of groove crosshatch angles (30°, 60°, and 90°) on friction in sliding contact between a textured high-speed steel disc against an AISI304 stainless steel pin was evaluated by a pin-on-disc test with a constant load. Moreover, the contact pressure distribution and stress concentration associated with each groove pattern were numerically analyzed using finite element method. The results demonstrated that employing a laser power of 20 W effectively produced groove geometries with the desired aspect ratio. Among the tested patterns, the surface textured with a 60° crosshatch angle exhibited the lowest coefficient of friction of 0.111 compared to 0.148 for the untextured surface. Finite element analysis further revealed that the 60° and 90° crosshatch patterns provided the most balanced combination of reduced mean pressure and controlled stress localization, which may reduce the friction under sliding conditions. These findings confirm that laser surface texturing, particularly with an optimized crosshatch angle, can significantly reduce the sliding friction and enhance the tribological performance of high-speed steel tools.