Future research directions in the machining of Inconel 718

Inconel 718 is the most popular nickel-based superalloy, extensively used in aerospace, automotive and energy industries owing to its extraordinary thermomechanical properties. It is also notoriously a difficult-to-cut material, due to its short tool life and low productivity in machining operations. Despite significant progress in cutting tool technologies, the machining of Inconel 718 is still considered a grand challenge.This paper provides a comprehensive review of recent advances in machining Inconel 718. The progress in cutting tools’ materials, coatings, geometries and surface texturing for machining Inconel 718 is reviewed. The investigation is focused on the most adopted tool materials for machining of Inconel 718, namely Cubic Boron Nitrides (CBNs), ceramics and coated carbides. The thermal conductivity of cutting tool materials has been identified as a major parameter of interest. Process control, based on sensor data for monitoring the machining of Inconel 718 alloy and detecting surface anomalies and tool wear are reviewed and discussed. This has been identified as the major step towards realising real-time control for machining safety critical Inconel 718 components. Recent advances in various processes, e.g. turning, milling and drilling for machining Inconel 718 are investigated and discussed. Recent studies related to machining additively manufactured Inconel 718 are also discussed and compared with the wrought alloy. Finally, the state of current research is established, and future research directions proposed.<br/

Future research directions in the machining of Inconel 718

Inconel 718 is the most popular nickel-based superalloy, extensively used in aerospace, automotive and energy industries owing to its extraordinary thermomechanical properties. It is also notoriously a difficult-to-cut material, due to its short tool life and low productivity in machining operations. Despite significant progress in cutting tool technologies, the machining of Inconel 718 is still considered a grand challenge.This paper provides a comprehensive review of recent advances in machining Inconel 718. The progress in cutting tools’ materials, coatings, geometries and surface texturing for machining Inconel 718 is reviewed. The investigation is focused on the most adopted tool materials for machining of Inconel 718, namely Cubic Boron Nitrides (CBNs), ceramics and coated carbides. The thermal conductivity of cutting tool materials has been identified as a major parameter of interest. Process control, based on sensor data for monitoring the machining of Inconel 718 alloy and detecting surface anomalies and tool wear are reviewed and discussed. This has been identified as the major step towards realising real-time control for machining safety critical Inconel 718 components. Recent advances in various processes, e.g. turning, milling and drilling for machining Inconel 718 are investigated and discussed. Recent studies related to machining additively manufactured Inconel 718 are also discussed and compared with the wrought alloy. Finally, the state of current research is established, and future research directions proposed.<br/

Prediction of Surface Quality Using Artificial Neural Network for the Green Machining of Inconel 718

Inconel 718 is a nickel-based heat resistant super-alloy (HRSA) that is widely used in many aerospace and automotive applications. It possesses good properties like corrosion resistance, high strength, and exceptional weld-ability but it is considered as one of the most difficult alloys to cut. Recently researchers have focused on employing many machining strategies to improve machinability of Inconel 718. This research work presents the experimentation of wet milling of Inconel 718 using a carbide tool with biodegradable oil. Surface quality is the major aspect of machinability. Hence input parameters such as depth of cut, cutting speed, and feed rate are considered to study their effect on surface quality. Nine experimental runs based on an L9 orthogonal array are performed. Additionally, analysis of variance (ANOVA) is applied to identify the most significant factors among cutting speed, feed rate, and depth of cut. Moreover, this research work presents the Artificial Neural Network (ANN) model for predicting the surface roughness based on experimental results. The ANN based-decision-making model is trained by using acquired experimental values. Visual Gene Developer 2.0 software package is used to study the efficiency of ANN. The presented ANN model demonstrates a very good statistical performance with a high correlation and extremely low error ratio between the actual and predicted values of surface roughness and tool wear

Face milling of nickel-based superalloys with coated and uncoated carbide tools

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Influence of Advanced Coated Tools on Machinability Characteristics of Incoloy 825

With vast application of nickel-based super alloys in strategic fields, it has become increasingly necessary to evaluate the performance of advanced cutting tools for machining such alloys. In order to have elementary knowledge on machinability characteris tics of Incoloy 825 which was so far unknown, in the initial stage of experiment, tool wear and its mechanism, chip characteristics and surface integrity during dry machining were first studied using uncoated and chemical vapour deposition (CVD) multilayer TiN/TiCN/Al2O3/ZrCN coated tool with different cutting speeds. The coated tool could not improve surface finish, but outperformed its uncoated counterpart in terms of other aspects. In the second stage of the study, the primary objective was to recommend suitable cutting tool for machining Incoloy 825. Detailed study was undertaken using commercially available uncoated, CVD and physical vapour deposition (PVD) coated carbide tools, the performance of which was comparatively evaluated in terms of surface roughness, cutting temperature, cutting force, coefficient of friction, tool wear and its mechanism during dry machining. Effect of cutting speed (VC) and feed (f) was also studied. Although, CVD coated tool was not useful in decreasing surface roughness and temperature compared to uncoated one, significant decrease in cutting force and tool wear could be achieved with the same coated tool even under high cutting parameters (Vc=124 m/min and f=0.2 mm/rev). On the other hand, PVD coated tool consisting of alternate layers of TiAlN/TiN outperformed the other tools in terms of all machinability characteristics that have been studied. This might be attributed to excellent anti-friction and anti-sticking property of TiN and good toughness which is a salient feature of PVD technique as well as multilayer configuration, in combination with thermally resistant TiAlN phase. In the final stage of the research work, the feasibility of best performing PVD coated tool was evaluated under environment-friendly dry machining condition in comparison with uncoated tool under conventional flood cooling and minimum quantity lubrication (MQL). Although temperature obtained with PVD coated tool under dry machining has always been significantly more than wet environment, the same coated tool remarkably brought down cutting force, surface roughness and tool wear under dry environment. The results achieved under both rough and finish modes of machining clearly established the use of PVD coated tool under dry environment as a sustainable strategy for achieving green machining of nickel-based super alloys

State-of-the-art cooling and lubrication for machining Inconel 718

Inconel 718 is the most used nickel superalloys with applications in aerospace, oil&amp;gas, nuclear and chemical industries. It is mostly used for safety-critical components where the condition of the surface is a significant concern. The combination of mechanical, thermal and chemical properties of Inconel 718, has made it a difficult-to-machine material. Despite recent advances in machining Inconel 718, achieving desired surface integrity with prescribed properties is still not possible. Different machining environments have been investigated for improving the machinability of Inconel 718 and enhance the surface integrity of machined components. This paper provides a new investigation and classification into recent advances in the machining of Inconel 718 regarding surface integrity, mostly concentrated on turning applications. The major findings and conclusions provide a critique of the state-of-the-art in machining environments for Inconel 718 together with future directions for research. Surface integrity has been evaluated in terms of surface topology as well as mechanical and microstructural properties. The impact of various cooling and lubrication methods has been investigated. It has been found that surface integrity is affected by the thermomechanical conditions at the cutting zone which are influenced by the cutting parameters, cutting tool, tool wear and cooling/lubrication condition. The current technologies are incapable of delivering both productivity and sustainability whilst meeting surface integrity requirements for machining Inconel 718. High-pressure cooling has shown the potential to enhance tool wear at the expense of higher power consumption

State-of-the-art cooling and lubrication for machining Inconel 718

Inconel 718 is the most used nickel superalloys with applications in aerospace, oil&amp;gas, nuclear and chemical industries. It is mostly used for safety-critical components where the condition of the surface is a significant concern. The combination of mechanical, thermal and chemical properties of Inconel 718, has made it a difficult-to-machine material. Despite recent advances in machining Inconel 718, achieving desired surface integrity with prescribed properties is still not possible. Different machining environments have been investigated for improving the machinability of Inconel 718 and enhance the surface integrity of machined components. This paper provides a new investigation and classification into recent advances in the machining of Inconel 718 regarding surface integrity, mostly concentrated on turning applications. The major findings and conclusions provide a critique of the state-of-the-art in machining environments for Inconel 718 together with future directions for research. Surface integrity has been evaluated in terms of surface topology as well as mechanical and microstructural properties. The impact of various cooling and lubrication methods has been investigated. It has been found that surface integrity is affected by the thermomechanical conditions at the cutting zone which are influenced by the cutting parameters, cutting tool, tool wear and cooling/lubrication condition. The current technologies are incapable of delivering both productivity and sustainability whilst meeting surface integrity requirements for machining Inconel 718. High-pressure cooling has shown the potential to enhance tool wear at the expense of higher power consumption

Study of Effect of Advanced PVD coating on Drilling of Nickel-Based Super Alloy Inconel 825

The drilling process of Inconel 825, a nickel-based superalloy, is very challenging due to the material properties, the operating conditions and the high quality requirements. Moreover because of its low thermal conductivity, heat is concentrated near the tool tip and unable to dissipate causing tool wear. The current study investigates the influence of advanced PVD coating on the tool in terms of its performance during drilling of nickel based superalloy Inconel 825. A cutting force model is developed and forces and torque is predicted for different parameter settings. Systematic comparisons are made between the drilling performance of coated and uncoated carbide tools by taking into account the surface roughness, thrust force and torque utilizing analytical model, simulation and experiments. Force and torque are found to be less in case of coated tool compared to uncoated counterpart. Surface finish was better at higher cutting speed for PVD coated tool. Chip thickening is observed because of the constraints exerted on the free flow of the chip in drilling. This chip resistance force is reduced using the coated tool as the results show