Machining Of Nickel-based Alloy Research Articles

Evaluation of Surface Roughness, Tool Wear and Chip Morphology during Machining of Nickel-Based Alloy under Sustainable Hybrid Nanofluid-MQL Strategy

Nickel-based super alloys exhibit high strength, oxidation and corrosion resistance; however, the machining of these alloys is a challenge that can be overcome with effective cooling/lubrication techniques. The use of a minimum quantity lubrication (MQL) technique is limited to lower cutting parameters due to the tremendous heat produced during the machining of Inconel 718. Sustainable and eco-friendly machining of Inconel 718 can be attained using MQL and lubricants based on nanofluids because of their improved heat transfer capabilities. For that purpose, the performance of hybrid nanofluid-MQL is examined. In this novel study, graphene and hexagonal boron nitride (hBN) nanoparticles are reinforced with palm oil and delivered to the machining interface using an MQL setup. The machining experiments are performed under the conditions of dry, wet, MQL and MQL with graphene/hBN deposited in palm oil. The machining performance under selected cutting conditions is assessed by analyzing the surface roughness, tool wear, chip morphology and surface quality of the machined workpiece. A comparison of results showcased the effectiveness of hybrid nanofluid-MQL with improvement in surface finish, reduction in tool wear and favorable chip forms concerning all other machining conditions.

Numerical predictions of orthogonal cutting–induced residual stress of super alloy Inconel 718 considering dynamic recrystallization

Manufacturing processes, such as machining, can produce residual stresses in products. Residual stress and its distribution can be the main factor influencing the fatigue life of machined components and has already been the subject of many experimental and numerical studies. The high-temperature condition, as a result of machining, makes a change in the microstructural properties of the material and consequently affect the mechanical properties of the workpiece. A major metal component of aircraft structure and engine components is nickel-based alloys due to their resistance to heat, corrosion, thermal fatigue, thermal shock, creep, and erosion. When these critical structural components in the aerospace industry are manufactured with the objective to reach high-reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of finish-machined surfaces. The residual stresses and surface alterations including white layer, depth of work hardening, micro-cracks, and oxidation induced by machining of nickel-based alloys are extremely critical due to safety and sustainability concerns. Integrated Computational Materials Engineering (ICME) links physics-based models to predict the performance of materials based on their processing history. The Johnson–Mehl–Avrami-Kolmogrov (JMAK) model is used to develop a microstructure-based modeling approach that takes into account dynamic recrystallization (DRX) that causes grain size changes. Allied with that, a grain size parameter on the flow stress behavior of the material is considered by adding a grain size-dependent term to the traditional Johnson–Cook (JC) model as a novel framework. The impact of the simulation of the orthogonal cutting process is implemented in a finite element method (FEM) model–based commercial software, ABAQUS-explicit, with a coupled Euler-Lagrangian (CEL) approach. By relying on the VUHARD user subroutine capabilities with Fortran language, ABAQUS-explicit can be steered to model the material behavior considering the term of DRX. The forecast capability of the developed model is assessed by comparison of the results by changing the depth of cut and cutting edge radius effect on the residual stress. Then, the correlation between the grain size evolution and temperature distribution by changing the cutting velocity is investigated.

Evaluation of the tool wear in the turning process of INCONEL 718 using PCD tools

The use of nickel-based alloys (superalloys) has an ever-growing demand because of the combination of mechanical properties and corrosion resistance even at relatively high temperatures. Those same properties, however, increase the challenge to increase the cost-benefit of the machining operations. Nickel superalloys are usually machined using coated cemented carbide inserts at relatively lower cutting speeds or ceramic inserts at higher cutting speeds. The use of PCD tools, despite widespread at the machining process of titanium alloys, regarding the machining of nickel-based alloys has almost no research data, especially for Inconel. This happens mostly because of the alloys’ iron content leading to graphitization of the diamond at the tool. This paper presents a study about the viability of PCD tools in the turning process of Inconel 718 in finishing conditions. The machinability was assessed under different tool rake angles, cutting speeds, feed rates, and minimum lubrication flow rates. The results were compared regarding the specific cutting pressure, average workpiece profile roughness, tool wear and wear mechanisms observed through electronic microscopy. The results indicate that the rake angle did not have a statistically significant influence for the evaluated machining conditions and the feed rate was the most significant parameter, as it is linked with the specific cutting pressure and workpiece roughness. Adhered material seemed to have protected the rake surface from attrition, which reduced the amount of wear particles that promote abrasion of the flank surface. However, the increase in MQL flow seems to destabilize the adhered material and promote more severe wear. Overall, microchipping and adhesion were the most important wear mechanisms.

New strategies for improvement of numerical model accuracy in machining of nickel-based alloy

Accuracy and reliability of the numerical results is one of the most important challenges in the scientific community for finite element modeling (FEM) of cutting processes. It becomes more essential in machining of difficult-to-cut materials such as nickel-based alloys where high thermo-mechanical loads are induced into the workpiece. In this paper, new strategies were adopted to improve accuracy of FE modeling of cutting process of Inconel718 superalloy. Firstly, a novel hybrid strategy was established to simultaneously calibrate controllable simulation parameters. It was implemented based on the design of experiment, intelligent systems and FEM of cutting process. Using validation with experimental results, a great improvement was obtained for prediction of cutting forces, maximum temperature, and chip geometry compared with numerical results obtained previously by conventional calibration procedure. At the second stage of the paper, a grain size-based flow stress was developed by implementation of advanced FORTRAN user-subroutine in FE code to take into account the effect of changes in material properties during the chip formation. According to the results, implementation of grain size based flow stress has a significant effect on enhancement of simulation accuracy. Finally, it can be concluded that, the innovated strategies presented in this paper provide fundamental and useful approaches to improve precision in modeling of other manufacturing processes.

BCCS Approach for the Parametric Optimization in Machining of Nimonic-263 alloy using RSM

Machining of nickel-based alloys is one of the testing undertakings in the current research knowledge. Wire Electrical Discharge Machine (WEDM) is a propelled machine apparatus, broadly used to cut hard metals like nickel, titanium and other super composite alloys. Determination of WEDM process parameters to yield the coveted level of execution measures like metal removal rate and surface roughness is significant from quality and financial perspectives. In the present work an endeavor has been made to examine the impact of WEDM process parameters, for example, pulse on time, pulse off time, peak current and servo voltage in machining of Nimonic-263 alloys. A focal composite face focused outline of Response Surface Methodology (RSM) has been utilized for exploratory arrangement. The noteworthiness of process parameters are assessed by ANOVA investigation. Scientific forecast models are produced for metal removal rate and surface roughness by response surface methodology. In this paper a novel Hybrid Bee Colony Cuckoo Search (BCCS) optimization algorithm is incorporated to boost the process performance. The outcome of RSM and BCCS is compared and it shows the execution of the BCCS is superior to that of RSM. The machining information gathered for the Nimonic-263 amalgam will be valuable for the organization respectively.

Influence of cutting parameters on the chip-tool interface temperature during the turning of Waspaloy

Abstract Waspaloy, as a nickel superalloy, is a difficult-to-machine material used for gas turbine engine components that require considerable strength and corrosion resistance at high operating temperatures. The machining of nickel-based alloys generates high temperatures at the cutting tool edge. This research investigated the relationship between cutting parameters and cutting temperature, using a remote temperature measurement method employing an infrared thermometer. In addition, the effects of cutting parameters on surface roughness were examined. Experiments were conducted on Waspaloy AMS5708 superalloy samples and a PVD TiAlN-TiN-coated WNVG 080404-IC907 carbide insert was used during the turning process. It was observed that the highest cutting speed and highest feed rate generated higher temperatures and higher surface roughness. Better surface roughness was obtained with the lowest feed rate, the highest cutting speed and the higher cutting depth. No cutting fluid was used in the experiments.

High speed machining of nickel-based alloys

The connection between rotor disc and blades in turbine applications is usually realised by complex profiled grooves. The profiled grooves are mostly manufactured by broaching processes. In compressor and fan applications, alternative cutting processes such as milling and broaching with more advanced cutting materials are already implemented. In turbine applications, where nickel-based alloys are used due to high forces and temperatures, the use of HSS-tools is still state of the art. Due to the low high temperature strength of this cutting material, cutting speeds do not exceed vc = 2-5 m/min. The use of alternative manufacturing processes for roughing therefore has a high potential. This paper presents experimental results on rough side milling of nickel-based alloys with whisker reinforced ceramics at cutting speeds up to vc = 1,500 m/min including wear behaviour and metallographic analysis. The results are compared to further alternative processes discussed to complement the broaching of profiled grooves and broaching with alternative tool grades.

The machinability of nickel-based alloys: a review

This paper presents a detailed review of the various types of nickel-based alloys available on a commercial basis and their development including alloying additions as well as processing techniques employed to achieve specific mechanical and/or chemical properties. Problems associated with the machining of nickel-based alloys as well as tool wear and the mechanisms responsible for tool failure are identified and discussed. The integrity of the machined surfaces and tool life are the most important considerations during machining. These and other factors governing the machinability of nickel-based alloys are mainly affected by notching of the cutting tool, primarily at the depth of cut region, as well as by flank wear and insert chipping/fracture; and by failure modes caused singly or jointly by diffusion, attrition, and abrasion wear mechanisms in addition to mechanical and thermal fatigue loading of the cutting tools. Most of the failure modes can be minimised when machining in the presence of coolants and in an oxygen-rich environment. The use of a high pressure coolant supply, despite improved chip segmentation and machining in the presence of argon and nitrogen-rich environments, tend to accelerate tool wear rate leading to lower tool life. Improvements in tool performance can be achieved with an increase in the included angle and/or the nose angle of cutting tools due to the increased edge strength and tool–chip contact area plus a reduction in the approach angle. Recently developed cutting tool materials such as mixed oxide, SiC whisker reinforced alumina ceramics, sialon and multi-layer coated cemented carbide cutting tool material have all exhibited the capability to machine nickel-based alloys at higher speed conditions than those achieved with conventional cemented carbide tools.