Tool Wear Reduction Effect of Oil-Immersion Treatment and its Surface Modification Mechanism

Abstract

This study describes a new surface treatment method that involves immersing sintered cutting tools into a high-pressure, high-temperature processing liquid. Cutting experiments were performed, and the results show that oil-immersion treatment helps reduce tool wear. However, this treatment limits the applications of treated carbide tools, e.g., they become unsuitable for heavy-cutting conditions. After the cutting test, surface analyses of the treated carbide tools were performed using FT-IR, SEM, EPMA, and XPS to verify the effect of oil-immersion treatment on tool-wear reduction. FT-IR analysis showed that, following oil-immersion treatment, trace quantities of the coolant remained on the tool surface, which could be readily removed by ultrasonic cleaning. Despite the removal of the processing liquid, the tool subjected to oil immersion exhibited less wear than the non-treated tool. SEM and EPMA examinations revealed that oil-immersion treatment reduced the amount of cobalt on the tool surface, forming sulfur deposits. EPMA analysis indicated that less cobalt binder was found on the surface after oil-immersion treatment, suggesting that the reduction in the amount of cobalt caused tungsten carbide particles to be exposed.