scholarly journals Fracture Toughness and Tribological Properties of Cemented Carbides Machined by Sinking Electrical Discharge Machining

2021 ◽  
Author(s):  
Timm Petersen ◽  
Ugur Küpper ◽  
Tim Herrig ◽  
Andreas Klink ◽  
Thomas Bergs
Keyword(s):  
Fracture Toughness ◽  
Tribological Properties ◽  
Electrical Discharge ◽  
Thermal Stresses ◽  
Electrical Discharge Machining ◽  
Bending Test ◽  
Cemented Carbides ◽  
Forming Process ◽  
Compressive Stresses ◽  
The Impact

The quality of a forming process highly depends on the pressure applied to the workpiece. Consequently, the demand for higher workpiece qualities results in a demand for tools that can withstand high compressive stresses. Moreover, the tendency of using materials like high-strength steels as workpiece material, urges the need for tool materials that can withstand high compressive stresses and are resistant to wear. A class of materials that offer a combination of hardness or wear resistance and ductility are cemented carbides. However, these properties hamper their machining with conventional cutting technologies. Due to its electro-thermal working principle, Electrical Discharge Machining (EDM) is able to machine materials independently from their mechanical properties. On the other hand, the removal process is accompanied by thermal stresses, which can cause residual stresses and micro cracks near the machined surface. Due to their pre-existing stresses from the sintering process, cemented carbides are especially susceptible for these kind of damages. It is therefore necessary to identify the impact of EDM on the material. Different machining strategies are tested with two different types of cemented carbides and examined regarding their fracture toughness. The crack surfaces resulting from the three point bending test are microscopically inspected regarding failure initiation. Additionally pin-on-disc tests are conducted to determine the influence of the EDM strategies on the tribological properties of the machined cemented carbides.

scholarly journals Surface Roughness Prediction for Steel 304 In Edm Using Response Graph Modeling

2018 ◽  
Vol 14 (4) ◽  
pp. 115-124 ◽  
Author(s):  
Shukry H. Aghdeab ◽  
Nareen Hafidh Obaeed ◽  
Marwa Qasim Ibraheem
Keyword(s):  
Surface Roughness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Applied Current ◽  
Graph Modeling ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
The Impact ◽  
Off Time

Electrical Discharge Machining (EDM) is a non-traditional cutting technique for metals removing which is relied upon the basic fact that negligible tool force is produced during the machining process. Also, electrical discharge machining is used in manufacturing very hard materials that are electrically conductive. Regarding the electrical discharge machining procedure, the most significant factor of the cutting parameter is the surface roughness (Ra). Conventional try and error method is time consuming as well as high cost. The purpose of the present research is to develop a mathematical model using response graph modeling (RGM). The impact of various parameters such as (current, pulsation on time and pulsation off time) are studied on the surface roughness in the present research. 27 samples were run by using CNC-EDM machine which used for cutting steel 304 with dielectric solution of gas oil by supplied DC current values (10, 20, and 30A). Voltage of (140V) uses to cut 1.7mm thickness of the steel and use the copper electrode. The result from this work is useful to be implemented in industry to reduce the time and cost of Ra prediction. It is observed from response table and response graph that the applied current and pulse on time have the most influence parameters of surface roughness while pulse off time has less influence parameter on it. The supreme and least surface roughness, which is achieved from all the 27 experiments is (4.02 and 2.12µm), respectively. The qualitative assessment reveals that the surface roughness increases as the applied current and pulse on time increases

CRUCIBLE S7 XL

Alloy Digest ◽  
2005 ◽  
Vol 54 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Heat Treating ◽  
Wire Electrical Discharge Machining ◽  
Wire Edm ◽  
High Purity Grade ◽  
Shock Resistance ◽  
Plastic Injection ◽  
Purity Grade

Abstract Crucible S7 XL is a double-refined high-purity grade of S7 tool steel (see Alloy Digest TS-543, July 1996) designed specifically for ease of wire electrical discharge machining (EDM) operations, improved consistency in texturizing of plastic injection molds, and superior shock resistance compared to conventional S7. Typical applications include plastic injection molds, punches and dies by wire EDM, and heavy impact tools. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on wear resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: TS-562. Producer or source: Crucible Service Centers. Originally published November 1998, revised 2005.

Influence of climate change on thermal stresses in concrete box girders

2021 ◽  
Author(s):  
Saad Saad ◽  
Rashid Bashir ◽  
Stavroula Pantazopoulou
Keyword(s):  
Climate Change ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Structural Model ◽  
Meteorological Data ◽  
Structural Response ◽  
Box Girders ◽  
Box Girder ◽  
Compressive Stresses ◽  
The Impact

<p>The purpose of this study is to investigate the impact of climate change on the thermal and structural response of concrete box girders. An advanced finite element platform was used to model a concrete box girder and analyze the additional thermal stresses that result from climate change. Meteorological data for future climate scenarios in Toronto, Canada was used as input in a thermal model to simulate the temperature distribution within the bridge deck. The temperature distribution was then used as input in a structural model of the bridge, to determine the resulting thermal stresses. The results show increases in tensile and compressive stresses as well as increased bridge movements. This study highlights the importance of explicitly considering climate change to achieve more robust bridge codes, particularly when it comes to thermal effects.</p>

Experimental Investigations on the Tribological Performance of Electric Discharge Alloyed Ti–6Al–4V at 200–600 °C

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Jibin T. Philip ◽  
Deepak Kumar ◽  
Jose Mathew ◽  
Basil Kuriachen
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Wear Behavior ◽  
Ex Situ ◽  
Experimental Investigations ◽  
X Ray ◽  
Before And After ◽  
Xrd Techniques ◽  
Pin On Disk ◽  
The Impact

Abstract Nowadays, the titanium alloys observe broad applicability in aerospace, marine, automobile, and bio-medical industries due to their lightweight, bio-compatibility, good fatigue strength, and corrosion resistance. However, it possesses poor tribological behavior characterized by a high coefficient of friction (CoF) and the specific wear rate (SWR). In this paper, the impact of the electrical discharge machining on the tribological properties of Ti6Al4V (Ti64) was compared before and after electrical discharge machining (EDM) using a pin-on-disk tribometer under un-lubricated and ambient temperature. Besides, ex-situ analysis was performed on the distinct pin surfaces using (i) scanning electron microscopy (SEM), (ii) energy-dispersive X-ray spectroscopy (EDX), and (iii) X-ray diffraction spectroscopy (XRD) techniques to elucidate the associated wear mechanisms. The mechanical properties such as nano-hardness and elastic modulus of the test surfaces were also determined using a nano-indenter. Significant improvement in SWR (65.44% reduction) with a passable compromise for CoF (22.5% increment) occurred during experimentation (before and after EDM) at 100 N. Besides, the wear behavior of the electrical discharge alloyed Ti64 (ETi64) was evaluated at 200 °C, 400 °C, and 600 °C under the applied loads of 50–150 N. At 400 °C and 600 °C, the SWR initially decreased and then increased with variation in load from 50–100 N and 100–150 N, respectively. The enhanced tribo-behavior at 100 N was due to the protective influence of tribo-oxides, viz., TiO2 and Ti8O15 assisted by the hard Ti24C15 carbides in the recast layer (RL).

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