Abstract
The formation of the complex oxide protective layer (Belag) on the worn surface of cutting tool when machined the Ca deoxidized steel was discovered by Opitz. Belag has been used as a free-cutting technique for steel and cast iron because it significantly reduces diffusion wear by preventing direct contact with a tool and work material, thereby prolonging the tool life dramatically. For the Belag formation, it′s one of the conditions to contain TiC in the tool material. It′s said that Belag adheres to the carbide tool surface because TiC in the tool oxidizes and reacts with Belag. Our work aims to clarify the formation and adhesion mechanism of Belag. In this study, Ca deoxidized steel was machined with carbide tools, and the state of the reaction at the interface between tool and the Belag layer was investigated by observation. As a result, Belag directly adhered to Ti carbide particle in the surface of the tool. On the other hand, on parts of WC and Co, Belag didn′t adhere directly. It could not confirm the oxide of TiC and its oxide layer near the interface that Belag adhered as said above.
