The effect of laser surface hardening on the wear and friction characeristcs of Acicular Baintic

Nd-Yag (Neodymium Yttrium) pulsed wave laser has been used to modify and refine the surface microstructure of acicular bainitic ductile iron. The wear characteristics evaluated by adhesion and abrasion wear tests while friction characteristics evaluated by using strain gauge technique of the laser processed and unprocessed (as-cast) specimens were studied. The wear and friction resistance of laser processed samples are significantly enhanced by their refined bainitic microstructures and improved hardness in the melted and resolidified layer. Cross-sectional optical and scanning electron microscope have been used to study the microstructure and wear mechanism of the laser processed and unprocessed surfaces while X-Ray diffraction technique has been used to study and estimate the metallurgical phases. Subsurface micro cracks generation and retained austenite phase have been observed. All specimens treated by laser showed wear and friction resistance higher than as-cast specimens at all loads, sliding speeds and sliding times used in this research work