Hard turning of AISI H10 steel using AlTiN and AlTiSiN coated carbide tools: comparative machining performance evaluation and economic assessment

This study focuses on comparative machining performance evaluation and economic assessment between recently developed nanocomposite AlTiSiN coating (deposited by scalable pulsed power plasma, S3P method) with AlTiN coated (accomplished by two different techniques, namely arc deposition method and the S3P technique) carbide tools in turning of hardened AISI H10 hot work steel (65 HRC) under dry environment. For the purpose of evaluating machining performance under different cutting factors (depth of cut, axial feed, and cutting speed), several machinability criteria (cutting temperature, crater wear, flank wear, chip morphology, surface roughness' and cutting force) were analyzed. Finally, a creative way concerning cost assessment for economical hard machining has been proposed. Due to the development of enhanced machined surface morphology, lower cutting force and minimum temperature, improved chip morphology, and reduced tool wear, it is highlighted that AlTiSiN coated tools are superior to both AlTiN (LATUMA) and S3P-AlTiN coated tools. S3P-AlTiN and AlTiN (LATUMA) were the same coating material; however, AlTiN performed better due to the smooth coating and higher micro-hardness gained by S3P technique. The tool life of AlTiSiN coated inserts is 17% and 55% longer, respectively, when compared to the tool life obtained while using S3P-AlTiN and AlTiN (LATUMA) coated tools for dry machining. According to the findings, the hard turning process employing an S3P-AlTiSiN coated carbide insert is more cost-effective in a dry environment than using AlTiN (LATUMA) and the S3P-AlTiSiN coated carbide inserts, with a minimal machining cost per component in Indian rupees of Rs. 27.53 compared to Rs. 30.93 and Rs. 28.93, respectively. The nanostructured AlTiSiN coating accomplished by S3P technique significantly reduced tool wear (VB = 0.061-0.136 mm), improved surface finish (Ra = 0.576-1.458 mu m), and higher surface quality, resembling cylindrical grinding.