scholarly journals EDMed Inconel 718 using powder metallurgy (P/M) sintered electrode made with nano and micron sized powders

2020 ◽  
Vol 40 (3) ◽  
pp. 52-64
Author(s):  
Rallabhandi Venkata Surya Subrahmanyam ◽  
Koona Ramji ◽  
Pujari Srinivasa Rao
Keyword(s):  
Powder Metallurgy ◽  
Inconel 718 ◽  
Nano Particles ◽  
Surface Alloying ◽  
Micro Hardness ◽  
Machined Surface ◽  
Peak Current ◽  
Reactive Surface Area ◽  
Pulse On Time ◽  
Sintered Electrode

This work presents experimental data carried out for surface modification of Inconel 718 using WC/Cu composite powder metallurgy (P/M) electrodes made of nano and micron sized particles. Both machine and tool parameters were selected for study and experiments were planned as per Taguchi’s L18 mixed orthogonal array in order to find the influence of parameters on surface roughness (SR) and micro-hardness (MH). Peak current, particle size and pulse on time were found to be most significant on both SR and MH. High reactive surface area of nano particles made surface alloying greater than the other tool electrodes and has shown its influence positively on both SR and MH. The EDX analysis reveals the migration of WC and Cu elements and deposition of carbon and oxygen particles on the surface. The XRD spectrum confirms presence of carbides (WC, W2C, Fe5C2, Cr7C3, Fe7C3 and Fe3C), oxides (Fe3O4, WO3 and Cr3O) and other intermetallics at different machining conditions indicating the influence of Pulse on time (TON) and Peak current (IP) on discharge energies and in turn on the properties of machined surface. The carbides generated on the machined surface increased the hardness to 845HV without much sacrifice of the roughness of the machined surface. The range of roughness values obtained in the present investigation is 2.443 to 4.098µm.

Evaluation of Surface Quality during Electrical Discharge Machining of Inconel 718 with Powder Metallurgy Electrodes

2011 ◽  
Vol 410 ◽  
pp. 245-248 ◽  
Author(s):  
Naveen Beri ◽  
S. Maheshwari ◽  
C. Sharma
Keyword(s):  
Powder Metallurgy ◽  
Surface Quality ◽  
Inconel 718 ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Evaluation Criteria ◽  
Inconel 718 Alloy ◽  
Machined Surface ◽  
Energy Dispersion Spectrum ◽  
Pulse On Time

In recent years, researchers have reported powder metallurgy processed electrodes as alternative tooling for electrical discharge machining (EDM). The present experimental study evaluates the quality of machined surface during electrical discharge machining (EDM) of Inconel 718 alloy steel with powder metallurgy (PM) processed electrodes. The investigated process parameters were polarity, electrode type, peek current, pulse on time, duty cycle, gap voltage, retract distance and flushing pressure. The surface quality was measured in terms of surface roughness (Ra). An orthogonal array L36 (21X 37) based on Taguchi methodology was applied to plan and design experiments. Experimental data was statistically analyzed using analysis of variance (ANOVA) and optimum condition was achieved for evaluation criteria. It was concluded that polarity, electrode type, peek current, have significant effect on surface quality and minimum Ra is obtained with CuW2080 electrode at minimum current and negative polarity. Deposition of tungsten with CuW2080 (80%W 20%Cu) electrode was confirmed by energy dispersion spectrum (EDS) of the machined surface.

Effect of Higher Peak Current and Pulse Duration on EWR of Copper Electrode when Electrical Discharge Machining (EDM) of Inconel 718

2013 ◽  
Vol 845 ◽  
pp. 945-949
Author(s):  
S. Ahmad ◽  
Mohd Amri Lajis
Keyword(s):  
Wear Rate ◽  
Pulse Duration ◽  
Electrode Surface ◽  
Inconel 718 ◽  
Copper Electrode ◽  
Work Piece ◽  
Electrode Wear ◽  
Peak Current ◽  
Electrode Wear Rate ◽  
Pulse On Time

In this work, the electrode wear rate (EWR) and electrode surface characteristic of copper electrode when EDM of Nickel Based Super Alloy, Inconel 718 at higher peak current and pulse duration were analyzed. Experiments were conducted using Inconel 718 as a work piece and copper as an electrode with a kerosene dielectric under different peak currents and pulse durations. Peak current, Ip within a range of 20A to 40A and pulse duration (or pulse on-time), ton within a range of 200μs to 400μs are selected as the main parameters. In this study, EWR were measured using digital weight balance (accuracy 0.01mg) and by using Scanning Electron Microscope (SEM), the surface texture of the electrode in order to evaluate the material deposited on the electrode surface. The results have shown that machining at a lowest peak current of 20A and highest pulse duration of 400μs yields the lowest electrode wear rate (EWR) of -0.01mm3/min. The pulse duration is significantly affecting the EWR. It also revealed that, the deposited of carbon and work piece material is occurred on the electrode surface for all machining conditions.

Optimization of machining characteristics for EDM of different nickel-based alloys by embodying of fuzzy, grey relational and Taguchi technique

2020 ◽  
Vol 18 (1) ◽  
pp. 23-36
Author(s):  
Sahil Sharma ◽  
Umesh Kumar Vates ◽  
Amit Bansal
Keyword(s):  
Inconel 718 ◽  
Machining Process ◽  
Simultaneous Optimization ◽  
Inconel 625 ◽  
Electrode Wear ◽  
Peak Current ◽  
Content Type ◽  
Grey Relational ◽  
Pulse On Time ◽  
Machining Characteristics

Purpose In the current exploration, the machinability of three different nickel-based super-alloy materials (Inconel 625, Inconel 718 and Nimonic 90) was experimentally investigated by using a die-sinking electrical discharge machining (EDM). The effect of changing important input process parameters such as pulse on time (Ton), off time (Toff), peak current (Ip) and tool rotation (TR) was investigated to get optimum machining characteristics such as material removal rate, roughness, electrode wear rate and overcut. Design/methodology/approach Experimentation has been performed by using Taguchi L9 orthogonal design. An integrated route of fuzzy and grey relational analysis approach with Taguchi’s philosophy has been intended for the simultaneous optimization of machining output parameters. Findings The most approbatory factors for machining setting have been attained as: (Ton = 100 µs, Toff = 25 µs, Ip = 14 A, TR = 725 rpm) for machining of Inconel 625 and Inconel 718; and (Ton = 100 µs, Toff = 75 µs, Ip = 14 A, TR = 925 rpm) for machining of the Nimonic 90 material. Peak current has been observed as an overall influencing factor to achieve better machining process. Microstructural study through SEM has also been carried out to figure out the surface morphology for the EDMed Ni-based super alloys. Originality/value The proposed machining variables and methodology has never been presented for Nimonic 90 alloy on die-sinking EDM.

Wire Electric Discharge Machining Induced Surface Integrity for Ni55.95Ti44.05 Shape Memory Alloy

2020 ◽  
pp. 095440892095114
Author(s):  
Himanshu Bisaria ◽  
Pragya Shandilya
Keyword(s):  
Surface Crack ◽  
Crack Density ◽  
Micro Hardness ◽  
Machined Surface ◽  
Surface Crack Density ◽  
Spark Gap ◽  
Wire Electric Discharge Machining ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time

The current study unveils the variation of surface integrity aspects (micro-hardness, surface crack density, and surface characteristics) for Ni55.95Ti44.05 shape memory alloy (SMA) with wire electric discharge machining (WEDM) process parameters, namely, pulse off time, wire tension, spark gap voltage, wire feed rate and pulse on time. The experimental results reveal that micro-hardness displays direct relationship with spark gap voltage, pulse on time, and pulse off time whereas surface crack density shows direct relationship with pulse on time and inverse trend with spark gap voltage and pulse off time. Wire tension and wire feed rate show trivial effect on both surface crack density and micro-hardness. Machined surface comprises crater, micro-cracks, micro-voids, pockmarks, and lumps of debris while inspecting through a scanning electron microscope (SEM). During energy-dispersive X-ray spectroscopy (EDS) analysis, the foreign elements namely carbon, oxygen, copper and zinc were also detected on the surface. The high energy density at higher pulse on time adversely affects the surface morphology. The formation of large size craters (deep and wide) with more cracks on the machined surface were observed at lower pulse off time as compared to higher pulse off time.

scholarly journals Improving micro-hardness of stainless steel through powder-mixed electrical discharge machining

2014 ◽  
Vol 228 (18) ◽  
pp. 3374-3380 ◽  
Author(s):  
Zakaria Mohd Zain ◽  
Mohammed Baba Ndaliman ◽  
Ahsan Ali Khan ◽  
Mohammad Yeakub Ali
Keyword(s):  
Stainless Steel ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Tantalum Carbide ◽  
Dielectric Fluid ◽  
Micro Hardness ◽  
Machined Surface ◽  
Surface Machining ◽  
Pulse On Time ◽  
Pulse Off Time

Powder-mixed electrical discharge machining (PMEDM) is the technique of using dielectric fluid mixed with various types of powders to improve the machined surface output. This process is fast gaining prominence in electrical discharge machining (EDM) industry. The objective of this investigation is to determine the ability of tantalum carbide (TaC) powder-mixed dielectric fluid to enhance the surface properties of stainless steel material during EDM. The properties investigated are the micro-hardness and corrosion characteristics of the EDMed surface. Machining was conducted with 25.0 g/L concentration of TaC powder in kerosene dielectric fluid. The machining variables used were the peak current, pulse on time and the pulse off time. The effects of these variables on the micro-hardness of the EDMed surface were determined. Corrosion tests were also conducted on the samples that exhibited higher hardness. Results showed that the EDMed surface was alloyed with elements from the TaC powder. The highest micro-hardness obtained with PMEDM is about 1,200 Hv. This is about 1.5 times that obtained without TaC powder in the dielectric fluid. The loss in weight during corrosion test was found to be 0.056 µg/min for the PMEDM which was much lower than the lowest value of 10.56 µg/min obtained for the EDM without powder dielectric fluid.

Simultaneous Improvement of Micro-Hardness and Surface Finish in Die Steels by Powder-Mixed EDM Process

2014 ◽  
Author(s):  
Sanjeev Kumar
Keyword(s):  
Surface Finish ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Dielectric Medium ◽  
Micro Hardness ◽  
Machined Surface ◽  
Die Steels ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time

Electrical Discharge Machining (EDM) is widely used by the die and tool making industry for the accurate machining of complex internal profiles in various types of dies. Due to the absence of physical contact between the tool and the workpiece, the hardness of the workpiece is not a consideration in this process and die steels can be machined after hardening. Although EDM is a machining process, it has also been successfully used for improving the surface properties of dies and press tools. The intrinsic nature or the process causes some dissolution of the electrode and these particles may alloy with the machined surface under appropriate machining conditions. Breakdown of the hydrocarbon dielectric under intense heat of the spark contributes carbon to the plasma channel. Another method to produce similar alloying effect is the addition of powders of the desirable elements in the dielectric medium. If such powders are conductive in nature, they affect the energy distribution and sparking efficiency and consequently, the surface finish and micro-hardness. This paper presents the results of an experimental study into electrical discharge machining of H13 hot die steel with graphite powder mixed in the dielectric medium. Copper electrode and kerosene dielectric were used for the experiments and three operating parameters, namely peak current, pulse on-time and pulse off-time were varied. Results show increase in micro-hardness by 42% and improvement in surface finish by 68%. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis show smooth surface devoid of any craters and significant presence of carbon in the machined surface which is expected to provide self-lubricating properties to the die surface. Chemical composition of the machined surface checked with an optical emission spectrometer shows increase in percentage of carbon from 0.44% to 3.23%. All three operating parameters emerge as significant and the favorable machining conditions for surface alloying are found to be low value of peak current, shorter pulse on-time, longer pulse off-time and negative polarity of the tool electrode.

Micro-hardness evaluation for surface alloying of H11 die steel with Cu–Cr–Ni powder metallurgy tool in electrical discharge machining

2016 ◽  
Vol 232 (3) ◽  
pp. 438-450 ◽  
Author(s):  
Amoljit Singh Gill ◽  
Sanjeev Kumar
Keyword(s):  
Powder Metallurgy ◽  
Energy Dispersive Spectroscopy ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Energy Dispersive ◽  
Tool Electrode ◽  
Surface Alloying ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray

Electrical discharge machining is a non-conventional material removal process; recently, efforts have been made to use it as a surface alloying/modifying method. This study investigates and compares the micro-hardness of the surface machined by electrical discharge machining process using composite tool electrode (copper–chromium–nickel) manufactured by powder metallurgy and conventional copper tool. Design of experiment is used to find the best level of process parameters in order to achieve high micro-hardness. The machined surfaces are subsequently analyzed using different techniques like scanning electron microscopy, X-ray diffraction and energy-dispersive spectroscopy to ascertain the surface characteristics. Results indicate that the micro-hardness of the alloyed surface formed by powder metallurgy tool electrode is improved by 96.3% as compared to base material and 65.7% as compared to the surface machined by conventional copper electrode. Energy-dispersive spectroscopy of the surface machined using powder metallurgy electrode confirms significant material migration from tool and dielectric to the machined surface. The X-ray diffraction shows the formation of cementite (Fe3C), intermetallic compound of iron, chromium and nickel (FeCrNi) and chromium carbide (Cr7C3) on the surface machined using powder metallurgy electrode.

Investigations on Effect of Electrode Polarity on Machining Performance of Ti-5Al-2.5Sn Alloy Using Electric Discharge Machining Process

2016 ◽  
Vol 1137 ◽  
pp. 39-51 ◽  
Author(s):  
Sanjeev Kumar ◽  
Rupinder Singh ◽  
Ajay Batish ◽  
T.P. Singh
Keyword(s):  
Removal Rate ◽  
Machining Process ◽  
Performance Criteria ◽  
Tool Electrode ◽  
Micro Hardness ◽  
Machining Performance ◽  
Peak Current ◽  
Electrode Polarity ◽  
Pulse On Time ◽  
Pulse Off Time

In electrical discharge machining (EDM) process, electrode polarity plays an important role during machining operation. This paper addresses the issues of EDM utilizing the positive and negative tool-electrode polarity to explore the effects on the performance criteria such as material removal rate (MRR), tool wear rate (TWR), surface roughness (SR) and micro-hardness during machining of Ti–5Al-2.5Sn (GradeVI) Ti alloy. The Ti-5Al-2.5Sn alloy was machined using copper-chromium electrode with positive and negative polarity by varying the peak current and pulse-on-time, while the pulse-off-time was kept constant. The result of study suggests that reverse polarity improves the MRR, TWR, SR while normal polarity improves the surface micro-hardness. The peak current has the maximum affect on machining performance for both types of polarities. Further the migration of different elements and formation of compounds on the machined surface was investigated using EDX and XRD analysis.

Effect of Powder-Mixed Dielectric on EDM Process Performance

2020 ◽  
Vol 38 (8A) ◽  
pp. 1226-1235
Author(s):  
Safa R. Fadhil ◽  
Shukry. H. Aghdeab
Keyword(s):  
Silicon Carbide ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
High Speed Steel ◽  
Transformer Oil ◽  
Dielectric Fluid ◽  
Peak Current ◽  
Powder Concentration ◽  
Pulse On Time

Electrical Discharge Machining (EDM) is extensively used to manufacture different conductive materials, including difficult to machine materials with intricate profiles. Powder Mixed Electro-Discharge Machining (PMEDM) is a modern innovation in promoting the capabilities of conventional EDM. In this process, suitable materials in fine powder form are mixed in the dielectric fluid. An equal percentage of graphite and silicon carbide powders have been mixed together with the transformer oil and used as the dielectric media in this work. The aim of this study is to investigate the effect of some process parameters such as peak current, pulse-on time, and powder concentration of machining High-speed steel (HSS)/(M2) on the material removal rate (MRR), tool wear rate (TWR) and the surface roughness (Ra). Experiments have been designed and analyzed using Response Surface Methodology (RSM) approach by adopting a face-centered central composite design (FCCD). It is found that added graphite-silicon carbide mixing powder to the dielectric fluid enhanced the MRR and Ra as well as reduced the TWR at various conditions. Maximum MRR was (0.492 g/min) obtained at a peak current of (24 A), pulse on (100 µs), and powder concentration (10 g/l), minimum TWR was (0.00126 g/min) at (10 A, 100 µs, and 10 g/l), and better Ra was (3.51 µm) at (10 A, 50 µs, and 10 g/l).

Optimization and surface modification in electrical discharge machining of AA 6061/SiCp composite using Cu–W electrode

2015 ◽  
Vol 231 (3) ◽  
pp. 332-348 ◽  
Author(s):  
Balbir Singh ◽  
Jatinder Kumar ◽  
Sudhir Kumar
Keyword(s):  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Electrode Wear ◽  
Material Transfer ◽  
Machined Surface ◽  
Recast Layer Thickness ◽  
Pulse On Time ◽  
Pulse Off Time

This paper presents the experimental investigation on the electro-discharge machining of aluminum alloy 6061 reinforced with SiC particles using sintered Cu–W electrode. Experiments have been designed as per central composite rotatable design, using response surface methodology. Machining characteristics such as material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR) have been investigated under the influence of four electrical process parameters; namely peak current, pulse on time, pulse off time, and gap voltage. The process parameters have been optimized to obtain optimal combination of MRR, EWR, and SR. Further, the influence of sintered Cu–W electrode on surface characteristics has been analyzed with scanning electron microscopy, energy dispersive spectroscopy, and Vicker microhardness tests. The results revealed that all the process parameters significantly affect MRR, EWR, and SR. The machined surface properties are modified as a result of material transfer from the electrode. The recast layer thickness is increased at higher setting of electrical parameters. The hardness across the machined surface is also increased by the use of sintered Cu–W electrode.

Sign in / Sign up

Export Citation Format

Share Document