Electrochemical machining of tungsten carbide

Schubert, N.; Schneider, M.; Michaelis, Alexander; Mańko, Maria; Lohrengel, M. M.

doi:10.1007/s10008-017-3823-9

Cited by 19 publications

(12 citation statements)

References 32 publications

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“…Electrochemical machining (ECM) of metals is increasingly gaining in importance in the field of subtractive manufacturing technology. In recent years, intensive research has opened up new application areas for the ECM process, for example, the production of turbine blades [ 1 , 2 ], the machining of difficult to cut materials [ 3 ] and the production of biomechanical implants [ 4 ]. The most important advantage of ECM is that even difficult-to-cut materials can be machined at high material removal rates with almost no tool wear [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining

et al. 2021

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The efficiency of material removal by electrochemical machining (ECM) and rim zone modifications is highly dependent on material composition, the chemical surface condition at the break through potential, the electrolyte, the machining parameters and the resulting current densities and local current density distribution at the surfaces. The ECM process is mechanistically determined by transpassive anodic metal dissolution and layer formation at high voltages and specific electrolytic compositions. The mechanisms of transpassive anodic metal dissolution and oxide formation are not fully understood yet for steels such as 42CrMo4. Therefore, martensitic 42CrMo4 was subjected to ECM in sodium nitrate solution with two different current densities and compared to the native oxide of ground 42CrMo4. The material removal rate as well as anodic dissolution and transpassive oxide formation were investigated by mass spectroscopic analysis (ICP-MS) and (angle-resolved) X-ray photoelectron spectroscopy ((AR)XPS) after ECM. The results revealed the formation of a Fe3−xO4 mixed oxide and a change of the oxidation state for iron, chromium and molybdenum, e.g., 25% Fe (II) was present in the oxide at 20.6 A/cm2 and was substituted by Fe (III) at 34.0 A/cm2 to an amount of 10% Fe (II). Furthermore, ECM processing of 42CrMo4 in sodium nitrate solution was strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.

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Section: Introductionmentioning

confidence: 99%

Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining

et al. 2021

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“…However, the tool wear is high, increasing costs [ 4 ]. In recent years, there has been a growing trend of using non-conventional methods, such as electric discharge machining (EDM) [ 5 ], electrochemical machining (ECM) [ 6 ], and laser machining [ 7 ], to process tungsten carbide products.…”

Section: Introductionmentioning

confidence: 99%

Micro Electrical Discharge Machining of Ultrafine Particle Type Tungsten Carbide Using Dielectrics Mixed with Various Powders

Gattu

Yan

2022

Micromachines

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Electrical discharge machining (EDM) is widely used to machine hard materials, such as tungsten carbide; however, the machining rate and surface quality are low. In this research, the effects of mixing electrically conductive carbon nanofiber (CnF), semiconductive silicon (Si) powder, and insulative alumina powder (Al2O3) at different concentrations in a dielectric fluid were studied by observing single discharge craters and hole machining performance in the EDM of ultrafine particle type tungsten carbide. Craters obtained using carbon nanofiber and alumina were much smaller than in oil-only conditions. In contrast, The results show that adding CnF significantly improved the material removal rate under all conditions. Si and Al2O3 powders only improved the machining performance at a high discharge energy of 110 V. Furthermore, improvement in surface roughness was observed prominently at high voltages for all the powders. Among the three powders, alumina was found to improve the surface roughness the most.

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“…Electrochemical machining (ECM) belongs to the substractive manufacturing processes and is relevant to several industries, such as the aerospace industry [ 1 , 2 , 3 ], the machining of hard-to-cut materials [ 4 , 5 , 6 ] and medical technology [ 7 ]. The concept of ECM is based on the transpassive anodic dissolution of the material surface.…”

Section: Introductionmentioning

confidence: 99%

Insights on the Influence of Surface Chemistry and Rim Zone Microstructure of 42CrMo4 on the Efficiency of ECM

et al. 2021

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The electrochemical machining (ECM) of 42CrMo4 steel in sodium nitrate solution is mechanistically characterized by transpassive material dissolution and the formation of a Fe3−xO4 mixed oxide at the surface. It is assumed that the efficiency of material removal during ECM depends on the structure and composition of this oxide layer as well as on the microstructure of the material. Therefore, 42CrMo4 in different microstructures (ferritic–pearlitic and martensitic) was subjected to two ECM processes with current densities of about 20 A/cm2 and 34 A/cm2, respectively. The composition of the process electrolyte was analyzed via mass spectrometry with inductively coupled plasma in order to obtain information on the efficiency of material removal and the reaction mechanisms. This was followed by an X-ray photoelectron spectroscopy analysis to detect the chemical composition and the binding states of chemical elements in the oxide formed during ECM. In summary, it has been demonstrated that the efficiency of material removal in both ECM processes is about 5–10% higher for martensitic 42CrMo4 than for ferritic–pearlitic 42CrMo4. This is on one hand attributed to the presence of the cementite phase at ferritic–pearlitic 42CrMo4, which promotes oxygen evolution and therefore has a negative effect on the material removal efficiency. On the other hand, it is assumed that an increasing proportion of Fe2O3 in the mixed oxide leads to an increase in the process efficiency.

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Electrochemical machining of tungsten carbide

Cited by 19 publications

References 32 publications

Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining

Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining

Micro Electrical Discharge Machining of Ultrafine Particle Type Tungsten Carbide Using Dielectrics Mixed with Various Powders

Insights on the Influence of Surface Chemistry and Rim Zone Microstructure of 42CrMo4 on the Efficiency of ECM

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