Arc-PVD coatings for titanium machining tool

The paper presents results of life tests in machining titanium alloy with cutting carbide tool with Ti-Mo-Al-Ni-Si-N, (Ti, Al) N coatings and without it. Shown, that tool life with first coatings is 1.8 and 3.6 times higher than tool with second coatings and simple carbide tool,respectively.

Method for assessing the thermophysical properties of the contact pair ‘tool – steel workpiece’

To The analysis of methods for evaluating the properties of contact pairs “hard -alloy coated tool-steel billet” is carried out in order to use them to increase the reliability of the choice of turning modes in the generations of CNC systems equipped with technological intelligence. It is proposed to use the value of the thermo-emf of the test pass as an indirect indicator of the properties of contact pairs composed of a coated carbide tool and a processed steel billet. Models for calculating the cutting speed based on a given tool durability period of a coated carbide tool and predicting the actual cutting tool durability period for given processing conditions are proposed by introducing into their structure an additional informative value about the properties of each contact pair - the thermo-EMF of the test pass. The conducted resistance tests of various carbide plates during the processing of P-group steels showed sufficient reliability of the proposed dependences.

Dry Machining of Inconel 825 Superalloys

The present work investigates application feasibility of PVD TiN/TiCN/TiN coated cermet and CVD Al2O3/TiCN coated SiAlON for dry machining of Inconel 825 superalloy. Machining performance is interpreted through cutting force magnitude, tool-tip temperature, and mechanisms of tool wear. Results are compared to that of CVD multi-layer TiN/TiCN/Al2O3/TiN coated WC-Co tool. It is evidenced that SiAlON tool generates lower cutting force but experiences higher tool-tip temperature than other two counterparts. Apart from abrasion and adhesion, carbide tool witnesses coating peeling and ploughing. In contrast, SiAlON tool suffers from inexorable chipping and notching. Wear pattern of cermet tool seems less severe than carbide and SiAlON. Chip's underside surface morphology appears relatively better in case of cermet tool.

Comparative assessment between AlTiN and AlTiSiN coated carbide tools towards machinability improvement of AISI D6 steel in dry hard turning

AISI D6 (hardness 65 HRC) is one of the hard-to-cut steel alloys and commonly used in mould and die making industries. In general, CBN and PCBN tools are used for machining hardened steel but its higher cost makes the use for limited applications. However, the usefulness of carbide tool with selective coatings is the best substitute having comparable tool life, and in terms of cost is approximately one-tenth of CBN tool. The present study highlights a detailed analysis on machinability investigation of hardened AISI D6 alloy die steel using newly developed SPPP-AlTiSiN coated carbide tools in finish dry turning operation. In addition, a comparative assessment has been performed based on the effectiveness of cutting tool performance of nanocomposite coating of AlTiN deposited by hyperlox PVD technique and a coating of AlTiSiN deposited by scalable pulsed power plasma (SPPP) technique. The required number of machining trials under varied cutting conditions (speed, depth of cut, feed) were based on L16 orthogonal array design which investigated the crater wear, flank wear, surface roughness, chip morphology, and cutting force in hard turning. Out of the two cutting tools, newly-developed nanocomposite (SPPP-AlTiSiN) coated carbide tool promises an improved surface finish, minimum cutting force, longer tool life due to lower value of crater & flank wears, and considerable improvement in tool life (i.e., by 47.83%). At higher cutting speeds, the crater wear length and flank wear increases whereas the surface roughness, crater wear width and cutting force decreases. Chip morphology confirmed the formation of serrated type saw tooth chips.