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This study aims to apply an electrochemical grinding (ECG) technology to improve the material removal rate (MRR) under the premise of certain surface roughness in machining U71Mn alloy.

The effects of machining parameters (electrolyte type, grinding wheel granularity, applied voltage, grinding wheel speed and machining time) on the MRR and surface roughness are investigated with experiments.

The experiment results show that an electroplated diamond grinding wheel of 46# and 15 Wt.% NaNO₃ + 10 Wt.% NaCl electrolyte is more suitable to be applied in U71Mn ECG. And the MRR and surface roughness are affected by machining parameters such as applied voltage, grinding wheel speed and machining time. In addition, the maximum MRR of 0.194 g/min is obtained with the 15 Wt.% NaCl electrolyte, 17 V applied voltage, 1,500 rpm grinding wheel speed and 60 s machining time. The minimum surface roughness of Ra 0.312 µm is obtained by the 15 Wt.% NaNO₃ + 10 Wt.% NaCl electrolyte, 13 V applied voltage, 2,000 rpm grinding wheel speed and 60 s machining time.

Under the electrolyte scouring effect, the products and the heat generated in the machining can be better discharged. ECG has the potential to improve MRR and reduce surface roughness in machining U71Mn.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2023-0341/

In the present research work electrochemical grinding (ECG) process is applied to machine Al₂O₃/Al interpenetrating phase composite. The purpose of this paper is to present a new approach to optimize the ECG process parameters while machining alumina-aluminum (Al₂O₃ – Al) interpenetrating phase composites (IPC) used in automotive, aircraft and manufacture of space ships applying Taguchi-based experimental studies and fuzzy multi-criteria decision-making techniques.

The present work identifies the process variables that have significant consequences during ECG of Al₂O₃/Al IPC. The Taguchi L₉ orthogonal array is selected for design of experiments and the analysis is carried out following signal to noise ratio. The analysis of variance is carried out to establish the factors that significantly influence the responses. The present work also investigates the multi objective optimization of ECG process parameters using VIseKriterijumsa Optimizacija I Kompromisno Resenje (VIKOR) and Grey relational analysis (GRA) to establish the reference ranking from a set of alternatives in the presence of conflicting criteria.

Material removal rate, surface finish, overcut and cutting force are shown to depend on the type of electrolyte, supply voltage, depth of cut and electrolyte flow rate. It is found that voltage and electrolyte concentration are important. The optimal machining parameter combination for ECG process is determined using fuzzy set theory, VIKOR and GRA. Substantial improvement in machining performance takes place.

A variety of manufacturing techniques are available for processing of Al₂O₃ – Al metal matrix composites. Generally manufacturers favor low cost modus operandi. Therefore ECG process is the best alternative for processing of MMCs in the present commercial sectors. The experimental investigation approach can act as useful and an efficient guideline for manufacturing.

The characteristic features of the ECG process are reflected through Taguchi design-based experimental studies with various process parametric combinations. Application of multi-response optimization technique for evaluation of best parametric combination for machining Al₂O₃ – Al IPC material using ECG process is a first-of-its-kind approach in literature.

To remanufacture a disused part, a hybrid process needs to be taken in part production. Therefore, a reasonable machining route is necessary to be developed for the hybrid process. This paper aims to develop a novel process planning algorithm for additive and subtractive manufacturing (ASM) system to achieve this purpose.

First, a skeleton of the model is generated by using thinning algorithm. Then, the skeleton tree is constructed based on topological structure and shape feature. Further, a feature matching algorithm is developed for recognizing the different features between the initial model and the final model based on the skeleton tree. Finally, a reasonable hybrid machining route of the ASM system is generated in consideration of the machining method of each different sub-feature.

This paper proposes a hybrid process planning algorithm for the ASM system. Further, it generates new process planning insights on the hybrid process service provider market.

The proposed process planning algorithm enables engineers to obtain a proper hybrid machining route before product fabrication. And thereby, it extends the machining capability of the hybrid process to manufacture some parts accurately and efficiently.

This study addresses one gap in the hybrid process literature. It develops the first hybrid process planning strategy for remanufacturing of disused parts based on skeleton tree matching, which generates a more proper hybrid machining route than the currently available hybrid strategy studies. Also, this study provides technical support for the ASM system to repair damaged parts.

This paper aims to develop an electrochemical abrasive jet machining (ECAJM) technology to investigate the surface machining effect of Ti-6Al-4V alloy.

First, the ECAJM equipment was set up, and a series of experiments for the surface machining of Ti-6Al-4V alloy was performed.

The experimental results show that the flowing abrasives of 0.05 Wt.% can effectively remove the TiO₂ oxide film of Ti-6Al-4V alloy surface. In addition, the flowing abrasives produce cutting machining effect on the surface of titanium aluminum alloy, and the oxide film can be removed effectively. For the case of machining pressure of 0.4 Mpa and machining gap of 0.4 mm, the processing efficiency can be achieved up to 20 µm/s.

Under different machining pressure, the flowing abrasive with high kinetic energy impacting the Ti-6Al-4V alloy surface and the oxide film produced from the electrolytic reaction process can be removed effectively, thereby enhancing the efficiency of electrochemical machining process.

DIFFICULT to machine, high temperature materials have been introduced at an ever increasing rate into aircraft propulsion systems over the last twenty five years. Over the same period, the aircraft industry has had an ‘on‐off’ affair with electrochemical machining (ECM).

Titanium has certain properties that make it an ideal material to prevent wear; titanium alloys lend themselves to a versatility of mechanical properties by heat treatment. This should provide a sound tribological combination but, unfortunately, these materials can cause serious galling and fretting. The authors describe the properties of titanium and its alloys, methods of forming and lubricating them and possible methods of combatting wear. In the second part, in our next issue, they will deal with diffusion, electrodeposition, electroless deposition of metallic coatings, and other ways of preventing fretting. In both parts an extensive review of published literature is made and all bibliographical references will be included in our next issue.

This study aims to shed light on the corrosion behavior of X80 steel when sulfate-reducing bacteria (SRB) and permeating hydrogen interact.

In this study, electrochemical tests were conducted between 25 and 55 °C, and the surface morphology of the specimen was observed using scanning electron microscopy and three-dimensional photos. The composition of the oxide film was characterized by X-ray photoelectron spectroscopy (XPS).

Under the condition of 6 MPa simulated natural gas (15% H₂), the content of S-containing compounds (FeS and FeSO₄) in the corrosion products on the surface of the specimen decreases from 60.8% to 54.4%. This finding indicates that hydrogen permeation inhibits the metabolic processes of SRB in this environment. By comparing the hydrogen-uncharged specimen, it was found that under the condition of 6 MPa simulated natural gas (15% H₂) hydrogen charging, the uniform corrosion on the X80 surface was weakened, and the protection of the oxide film on the specimen surface in this environment was better than that without hydrogen charging.

To the best of the authors’ knowledge, most of these existing studies have focused on the effect of hydrogen on the mechanical properties of materials and very little is known about corrosion behavior in the hydrogen environment. In this study, a self-designed small gas phase hydrogen charging device was used to study the X80 surface corrosion behavior in the environment of the H₂-doped natural gas pipeline.

The aim of this paper was to study the initial corrosion behavior of copper in the substations of Zhanjiang and Zhuhai.

The copper exposed at the substation of Guangdong coastal region in southern China for up to 12 months. The rust layer formed on the copper has been examined by scanning electron microscopy, X-ray energy spectrum, X-ray diffraction and electrochemical polarization techniques.

The corrosion weight loss of copper at Zhanjiang exposure site is a little more serious than that at Zhuhai exposure site in every exposure period. The corrosion products of copper have different changes in color and composition at the two exposure sites. The tensile strength of copper has a slight decrease after one-year exposure.

The atmospheric exposure experiments of copper in the substations of Zhanjiang and Zhuhai have been adopted for the first time. The corrosion behavior of copper was investigated, and it can provide reference for material selection of the substation.

Utilizing electrical discharge machining (EDM) to process micro-holes in superalloys may lead to the formation of remelting layers and micro-cracks on the machined surface. This work proposes a method of composite processing of EDM and ultrasonic vibration drilling for machining precision micro-holes in complex positions of superalloys.

A six-axis computer numerical control (CNC) machine tool was developed, whose software control system adopted a real-time control architecture that integrates electrical discharge and ultrasonic vibration drilling. Among them, the CNC system software was developed based on Windows + RTX architecture, which could process the real-time processing state received by the hardware terminal and adjust the processing state. Based on the SoC (System on Chip) technology, an architecture for a pulse generator was developed. The circuit of the pulse generator was designed and implemented. Additionally, a composite mechanical system was engineered for both drilling and EDM. Two sets of control boards were designed for the hardware terminal. One set was the EDM discharge control board, which detected the discharge state and provided the pulse waveform for turning on the transistor. The other was a relay control card based on STM32, which could meet the switch between EDM and ultrasonic vibration, and used the Modbus protocol to communicate with the machining control software.

The mechanical structure of the designed composite machine tool can effectively avoid interference between the EDM spindle and the drilling spindle. The removal rate of the remelting layer on 1.5 mm single crystal superalloys after composite processing can reach over 90%. The average processing time per millimeter was 55 s, and the measured inner surface roughness of the hole was less than 1.6 µm, which realized the  micro-hole machining without remelting layer, heat affected zone and micro-cracks in the single crystal superalloy.

The test results proved that the key techniques developed in this paper were suite for micro-hole machining of special materials.

This study aims to investigate the inhibition performance of an aqueous extract of Matricaria recutita chamomile on the corrosion of S235JR steel in 0.5 M NaCl by using electrochemical impedance spectroscopy (EIS) and polarization measurements.

The inhibition performance was investigated using EIS and polarization measurements. Surface analysis demonstrates the presence of a protective layer on the steel surface in the presence of the extract. Quantum chemical parameters calculated for the molecules contained in the aqueous extract are interpreted to predict the corrosion inhibition efficiency of the considered extract.

The inhibition efficiency of chamomile aqueous extract for S235JR steel increases with increasing amounts of plant concentration and with an increase in the immersion time. The optimal inhibition efficiency of chamomile extract, 98.90 per cent, was achieved for S235JR steel when immersed in 15 per cent v/v of extract concentration for 2 h. The surface analysis in the absence and presence of the chamomile extract confirmed the formation of a protective layer on steel surface. The quantum chemical calculations allowed to explain the great inhibition efficiency values by interpreting the calculated quantum parameters.

This is the first study carrying out an experimental and theoretical investigation on M. recutita chamomile as a green corrosion inhibitor, with interesting potential industrial applications.