scholarly journals The effect of SiC powder mixing electrical discharge machining on white layer thickness, heat flux and fatigue life of AISI D2 die steel

2016 ◽  
Vol 19 (3) ◽  
pp. 1400-1415 ◽  
Author(s):  
Ahmed Al-Khazraji ◽  
Samir Ali Amin ◽  
Saad Mahmood Ali
Keyword(s):  
Heat Flux ◽  
Fatigue Life ◽  
Layer Thickness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
Powder Mixing ◽  
White Layer Thickness ◽  
Die Steel ◽  
Aisi D2

Evolution of White Layer and Residual Stress in Electrical Discharge Machining

2021 ◽  
Author(s):  
Guisen Wang ◽  
Fuzhu Han ◽  
Liang Zhu
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Layer Thickness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
Machining Parameters ◽  
Discharge Energy ◽  
White Layer Thickness

Abstract White layer and residual stress are the main reasons for the decrease in fatigue life of electrical discharge machined samples. Therefore, it is important to research the evolution of the white layer and residual stress in electrical discharge machining and explain the influence mechanism of machining parameters on them. In this study, the surface topography, white layer thickness, and residual stress of electrical discharge machined samples under different processing parameters were evaluated. The results indicated that surface roughness, white layer thickness, and residual stress increased as the discharge current (I) and pulse-on time (ton) increased. However, when the ton was short, the effect of I (≤ 9.8 A) on surface roughness is not very obvious. When the discharge energy is similar, surface roughness is high under high I conditions. When the discharge energy is similar and low, the average thickness of the white layer is thin under the low I. The effect of I on surface residual stress was greater than that of the ton. The I and ton affect the white layer and residual stress by affecting the amount of melting and removal of the materials. These results were demonstrated that the input process of discharge energy has an important influence on residual stress and the white layer. Therefore, under the premise of ensuring the processing requirements, they can be controlled by selecting the appropriate combination of the ton and I to improve the fatigue life of the workpiece.

The Effect of Electrical Discharge Machining Total Heat Generated on White Layer Thickness (WLT) and Fatigue Life for Die Steel

2021 ◽  
Vol 1039 ◽  
pp. 182-200
Author(s):  
Saad Mahmood Ali ◽  
Ahmed Al-Khazraji ◽  
Samir Ali Amin
Keyword(s):  
Heat Flux ◽  
Layer Thickness ◽  
Safety Factor ◽  
White Layer ◽  
Setting Time ◽  
Total Heat ◽  
Model Errors ◽  
White Layer Thickness ◽  
Die Steel ◽  
Transient Thermal

The present paper concerns with studying the high complexity nature of the EDM multiple discharge analysis transformed into a feasible solvable mathematical model for the die steel workpiece type AISI D2, the copper and graphite materials electrodes, and the kerosene dielectric by setting the Transient Thermal and the Multiphysics analyses domain loads models using the ANSYS 15.0 finite element analysis. Two load steps modeled the entering setting time analysis, six sub-periods setting time cycle, four heating, and two cooling periods, six transient temperature values, and four transient thermal convection models. The radius spark (discharge channel), the total number of discharges sparks, the total heat power generation, the absorbed heat flux fractions by the electrodes, the workpieces and kerosene fluid dielectric, the heat-affected zones (HAZ), the hard white recast layer thickness (WLT) and properties, the workpiece fatigue safety factor and life after EDM machining were determined and simulated. The thermal model errors compared with theoretical calculations and a modeled predicted equation were also deduced and verified. The experimental results evinced that the maximum total heat flux generated using the graphite material electrodes is (2.619E+009 W/m2) which is higher than when using copper material electrodes by (82.4%), while the minimum value of the white layer thickness (WLT) after EDM machining using graphite tool electrodes is (8.34 μm), which it gives an improvement comparing with using of copper tool electrodes by (40.0%). The macrographic and microstructure evaluation manifest that the discharge spark craters sizes when using graphite tool electrodes reached their sizes. The maximum fatigue stresses and fatigue safety factor when using copper tool electrodes are (240 MPa) and (0.89) which is higher by a value of (3.35%) and (3.45%) comparing with the using of graphite electrodes, respectively.

Correlation of surface roughness and recast layer thickness in electrical discharge machining

2015 ◽  
Vol 231 (3) ◽  
pp. 414-424 ◽  
Author(s):  
Yakup Yildiz ◽  
Murali M Sundaram ◽  
Kamlakar P Rajurkar ◽  
Ahmet Altintas
Keyword(s):  
Surface Roughness ◽  
Layer Thickness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
Processing Technique ◽  
Recast Layer ◽  
Image Processing Technique ◽  
Recast Layer Thickness ◽  
Two Parameters

Electrical discharge machining (EDM) is an extensively used method in the machining of electrically conductive materials. Recast or white layer formation is undesirable, but inevitable, result of EDM and needs to be understood and accurately determined to efficiently perform post-treatment processes for removing the recast layer caused by EDM process. In this study, recast layer thickness and surface roughness data obtained from experimental study were analyzed and a correlation between these two parameters has been established. Image-processing technique has been used for obtaining of recast layer thickness data. It was observed that the correlation between recast layer thickness and surface roughness increases remarkably with the increase of working current and pulse time. The correlation obtained in this study has the potential to predict the recast layer thickness on spark-eroded surfaces from simple surface roughness values instead of using the prevailing time-consuming and tedious etching and polishing method. The possible approximation of the recast layer thickness using a thermal model is also discussed.

scholarly journals Multi-objective optimization in titanium powder mixed electrical discharge machining process parameters for die steels

2020 ◽  
Author(s):  
Phan Nguyen Huu
Keyword(s):  
Process Parameters ◽  
Electrical Discharge ◽  
Titanium Powder ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
Multi Objective Optimization ◽  
Die Steel ◽  
Multi Objective ◽  
Powder Concentration ◽  
Optimal Material

Abstract In this paper, we propose a viable optimal solution for achieving multi-objective optimization in powder mixed electrical discharge machining (PMEDM) process parameters, using titanium powder. Taguchi–AHP–Deng’s method is used to solve the multi-criteria decision making (MCDM) problem for this technology. The process parameters selected are workpiece material, electrode material, electrode polarity, pulse on time (Ton), pulse off time (Tof), current (I), and powder concentration. The material removal rate (MRR), tool wear rate (TWR), surface roughness (SR), hardness surface (HV), and white layer thickness (WLT) were determined simultaneously. The results showed that the optimal material for the workpiece is SKD11 die steel; the optimal material for the electrode is Gr; and the polarity of the electrode should be positive. The optimal values for the other process parameters were determined to be Ton = 20 μs, Tof = 57 μs, and I = 8 A, and that for the powder concentration was 10 g/l. The quality criteria for the optimal process parameters were determined to be MRR = 59.669 mm3/min, TWR = 14.073 mm3/min, SR = 4.45 μm, HV = 907.64 HV and WLT = 8.56 μm. The results were verified through experiments, which revealed a good accuracy (error ≈ 11.67%). The white-layer formation on the machined surface was reduced using titanium powder-based PMEDM for die steel at the optimal conditions. The results showed that Deng’s similarity method is the most suitable for MCDM in PMEDM using titanium powder.

Comparison of material transfer in electrical discharge machining of AISI H13 die steel

2009 ◽  
Vol 223 (7) ◽  
pp. 1733-1740 ◽  
Author(s):  
S Kumar ◽  
R Singh ◽  
T P Singh ◽  
B L Sethi
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Tungsten Powder ◽  
Material Transfer ◽  
Die Steel ◽  
Cent Increase ◽  
Aisi H13 ◽  
Copper Chromium ◽  
H13 Die Steel ◽  
And Tungsten

The electrical discharge machining (EDM) process is extensively used in the tool and die making industry for accurate machining of internal profiles in hardened materials. Although it is essentially a material removal process, efforts have been made in the recent past to use it as surface treatment method. This article investigates and compares the effect of material transfer from electrode bodies (copper, copper—chromium, and copper—tungsten) and tungsten powder suspended in the dielectric medium during die-sinking EDM of AISI H13 die steel. Results show a 76 per cent increase in micro-hardness by machining with a copper—tungsten electrode and a 111 per cent increase by machining with tungsten powder mixed in the dielectric. The copper—chromium electrode gives the best surface roughness (Ra) value of 2.67 μ m. Scanning electron microscopy and X-ray diffraction analysis of the machined surfaces show alloying of parent material with tungsten and tungsten carbide. Chemical composition of the machined surfaces was further checked on an optical emission spectrometer to verify the results. Besides a significant presence of tungsten, an increase in the percentage of carbon is also observed.

Sign in / Sign up

Export Citation Format

Share Document