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

Abstract

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.

An investigation on cutting sound effect on power consumption and surface roughness in CBN tool-assisted hard turning

“…The same results were found by many researchers. [32][33][34] According to Figure 6(c), the sharp increment in surface slope was noticed with leading feed which confirmed the dominant consequence of feed over surface roughness. ANOVA also stated the equivalent results that the surface roughness was highly dominated by feed with 87.71% contribution.…”

Effects of shallow cryogenic treatment on surface characteristics and machinability factors in hard turning of AISI 4140 steel

“…In hard turning, industrially acceptable tool performance can be obtained from carbide cutting tools. [11][12][13][14][15][16] In addition to the adequate resistance of the cutting tool to wear, quality requirements of the machined part must also be met in hard turning. The surface roughness is a significant quality factor in hard turning.…”

“…In hard turning, industrially acceptable tool performance can be obtained from carbide cutting tools. 11–16…”

Machining characteristics investigations of duplex stainless steel by considering dual effect of chip breaker and cooling conditions

“…24,25 The improvement in tool materials, coating qualities and tool geometries, and the application of optimal cutting parameters have enabled dry machining of some materials and contributed to sustainable manufacturing without using cutting fluids. [26][27][28] The different air types such as chilled, mist, cold, and cryogenic are used as a cryogenic condition in machining. 29,30 The compressed cold air in metal cutting is the cleanest, cheapest, and eco-friendly method.…”