Dry turning of AISI D3 steel using a mixed ceramic insert: A study

AISI D3 steel is a new kind of hardened tool steel with excellent wear resistance. This hard material receives wide promotion, investigation, and application in the die manufacturing industries. In the machining of AISI D3 steel, tool wear has a close relationship with the presence of different constituent elements in the workpiece material and cutting conditions. This study reports an improved experimental investigation approach to the analysis of effect of cutting speed, feed rate, and depth of cut on cutting forces, surface roughness, tool wear, and chip morphology in high-speed turning of AISI D3 steel using a hybrid TiN-coated Al2O3 + TiCN mixed ceramic insert. The range of each parameter is set at different levels for the analysis purpose. The experimental observations show that the cutting force is predominantly influenced by the feed rate accompanied by the depth of cut. The predominant factor influencing flank wear is the feed rate accompanied by the depth of cut and cutting speed. Feed rate is one of the dominating factors that influences the surface finish characteristics. The characterization of tool wear and chip morphology was performed by a scanning electron microscope supplied with energy-dispersive X-ray spectroscopy pattern. The results demonstrated that the predominant wear mechanism of the multilayered hybrid-coated tool was flank wear, crater wear, adhesion wear, and abrasive wear.

Comparison on various machinability aspects between mixed and reinforced ceramics when machining hardened steels

The hard turning process has an attracting interest in different industrial sectors for finishing operations of hard materials. However, it still presents disadvantages with respect to process capability and reliability. This paper describes a comparison of surface roughness, specific cutting force and flank wear between mixed ceramic CC650 (Al2O3 (70%) + TiC (30%)) and reinforced ceramic CC670 (Al2O3 (75%) + SiC (25%)) cutting tools when machining in dry hard turning of AISI 4140, treated at 52 HRC using the response surface methodology (RSM). A mathematical prediction model of the machining responses has been developed in terms of cutting speed, feed rate and cutting time parameters. Experimental observations show that the surface roughness obtained with the mixed ceramic insert significantly improved when compared with reinforced ceramic insert with a ratio of 1.44. In the same way, insert CC650 has better performance compared to reinforced ceramic inserts CC670, in terms of the specific cutting force and flank wear.