Wear mechanism and tool life prediction of high-strength vermicular graphite cast iron tools for high-efficiency cutting

Abstract

Vermicular graphite cast iron is not used widely because of the challenges associated with to processing. This study investigates the tool wear morphology and main wear mechanism during the turning of high-strength vermicular graphite cast iron using coated ceramic tools. Further, it develops a tool life prediction model, based on the grey theory, for the flank face of the tool. The results show that coated ceramic tools are more suitable than cemented carbide tools for the turning of vermicular graphite cast iron. Coated ceramic tools mainly exhibit adhesive, abrasive, and diffusion wear during low-speed cutting wherein the turning speed Vc≤200m/min. The FeO layer formed by the oxidation of the workpiece attached to the tool tip can appropriately reduce the tool wear. During high-speed cutting (Vc>400m/min), coated ceramic tools mainly show oxidative and diffusion wear and a certain degree of abrasive wear. As the turning speed increases, the diffusion wear of coated ceramic tools initially increases and then decreases. The analysis of the model prediction results shows that the short-term prediction error of the grey model is less than 5%.