Employing preheating- and cooling-assisted technologies in machining of Inconel 718 with ceramic cutting tools: towards reducing tool wear and improving surface integrity

Abstract

This paper is motivated by the fact that machining of Inconel 718 involves rapid tool wear and poor surface integrity. We investigate the performance of ceramic cutting inserts in turning of Inconel 718 by virtue of two different assisted machining conditions, plasma preheating-and cryogenic cooling-assisted technologies. The plasma nozzle placed in front of the cutting zone is used to soften the materials before machining. The liquid nitrogen flow located in the cutting area is used to reduce the cutting temperatures in the contact area. The cutting experiments are set for reducing tool wear and improving surface integrity, including surface roughness and micro-hardness beneath workpiece surface. With these two assisted techniques, the tool wear including flank wear and notch wear and the surface microstructure including surface roughness and micro-hardness are assessed and compared with conventional machining. Tool wear reduction and surface integrity improvement can be obtained with these two assisted technologies in turning of Inconel 718 with ceramic cutting inserts. The main causation of notch wear of the ceramic cutting inserts may be the hardened layer beneath the surface. By comparing these two assisted cutting techniques with opposite effects on the cutting tool and workpiece, it has been found that the surface roughness is reduced by 50 %, the micro-hardness is smaller, and the tool life is extended up to more than 40 % over conventional machining.

Influence of Cutting Speed and Feed Rate on the Wear of an S-Type Mixed Ceramic Tool in Turning of AISI 4140 Hardened Steel

“…The crater identified in the tools primarily appears due to the diffusion wear mechanism once the presence of carbon (C) from the titanium carbide (TiC) of the ceramic plate matrix produces chemical affinity between the elements in the machined piece. Similar results have been cited in other studies [12,14,19,[27][28][29][30][31][32].…”

Surface damages and tool wear mode in end milling of hastelloy‐C276 under dry and wet conditions

“…Dry machining resulted also in more spalling (coating delamination) at the tool edges, Figure 12c, d. The higher content of tungstenwhich is substrate materials, and the lower content of titaniumwhich is coating material, on the tool face in dry machining [33]. Similarly, it was observed previously in machining Inconel-718 that there is less adhesion but higher abrasion in dry machining in comparison to cryogenic machining [19].…”

“…The absence of coolant in dry micro‐drilling of Inconel‐718 was found to result in higher diffusion of workpiece material into tool coating, higher tendency of adhesive wear and larger chipping at the cutting edge in comparison to wet machining . On a study done on turning Inconel‐718 in dry and cryogenic machining, adhesive tool wear occurred mainly in cryogenic machining while severe abrasion took place in dry machining . The lower surface roughness obtained in cryogenic machining was attributed to the efficient chips evacuation.…”

An Investigation on Surface Roughness and Tool Wear in Turning Operation of Inconel 718

“…Although there are several investigations into the machining of Inconel 718, it is still challenging to understand the nature and actual reasons behind the disadvantage of the machining of Inconel 718 to improve productivity and quality in manufacturing. In the most of early studies on Inconel 718, surface roughness was used as a key output and process parameters have been tuned to improve the surface quality of machined products (Zhuang et al 2015;D' Addona et al 2017;Mohsan et al 2017;Cantero et al 2018;Mehta et al 2018). Guo et al (2009) overviewed the machining characteristics of difficult-to-cut materials, including nickel-based alloys.…”