An Evaluation of the Tool Wear of Ceramic and Coated Carbide Inserts in Finishing Turning under the Influence of Age-Strengthening Gray Cast Iron

Abstract

Gray cast iron (GCI) is a common material in the automotive industry due to its mechanical characteristics, which change primarily for materials employed for the foundry and cooling rate of material. According to the workpiece, the material of the cutting tool and cutting parameters are analyzed to improve the machining and to increment the lifetime of the tools. In this research, the foundry and machining process of an automotive component using ceramic and coated carbide tools were the study case, and the effect that they have on the age strengthening of GCI on the tool wear of the cutting tools was studied. Both inserts have the capability to machine the material with a rough surface between 1.5 to 2.0 μm. The wear mechanism of inserts and the microstructure of GCI were characterized with microscopy techniques, atomic force microscope (AFM), and energy dispersive X-ray spectroscopy (EDS). The microstructure of the workpiece shows a casting with flake graphite morphology that is linked with the induction of microcracks in the material. The experimental analysis shows that the GCI with 12 days of aging has an increased tensile strength. This improves the tool life of ceramic and coated carbide tools. There is a 50% reduction in flank wear with inserts that are machined with the GCI within five days of aging, compared with the material within twelve days. The rake face and flank wear show that abrasive and adhesive wear are the main mechanisms of ceramic inserts due to the high cutting speed. Meanwhile, adhesive and oxidative wear in the flank were the predominant type of wear for coated carbide tools.

Keywords

• gray cast iron
• age strengthening
• flank wear
• rake face and microscopy