Advanced Materials Research Vol. 1178

Abstract: A material with exceptional levels of abrasion resistance, compressive strength, and hardness is known as bearing steel, also known as EN-31 high-grade carbon alloy steel. It has several uses, including the bulk manufacturing of roller bearings, taps, gauges, ejector pins, swaging dies, etc. The lowest surface roughness (Ra) and highest material removal rate (MRR) are sought for this alloy steel in order for it to be used successfully in a range of applications. In the experiment, a L9 Taguchi orthogonal array design was used to CNC end mill EN-31 steel using a bullnose end mill carbide tool with inserts. This study presents a way for enhancing process factors such as cutting speed, depth of cut, feed rate, and tool corner radius that result in desirable output responses. Taguchi and Taguchi-Grey analyses are used to show the best input values that reduce surface roughness and increase MRR. The lowest level of surface roughness could be attained using the operating parameters of 3000 rpm cutting speed, 500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius, while the highest level of material removal rate could be attained using 3000 rpm cutting speed, 2500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius.

Abstract: Due to outstanding material qualities such as higher strength to weight ratio, resistance to corrosion and resistance to fatigue, titanium alloys (Ti-6Al-4V) are widely applied in aerospace industries. Such a challenging to machine and necessary expensive convenctional machinery materials can cut using Electrical Discharge Machining (EDM). This work involves the study of influence of process characteristics on the performance quality of EDM during machining of Ti-6Al-4V. The process characteristics that are considered in this study are Current (9-15amps) or Input power (I.P. of 3-5 kVA), pulse on (60-80 μsec) and pulse off (20-40μsec) times, the pressure of dielectric fluid (6-10 MPa). The effectiveness of the EDM is measured using rate of tool wear (TWR) and rate of material removal (MRR) during machining, taper angle and surface roughness (SR). Dry brass multi hole tool electrode is used along with deionized water as the dielectric medium. Taguchi L18 orthogonal design is used for experimentation. The optimal combination of process characteristics is determined.

Abstract: The current research paper is focused on investigating the influence of Laser beam machining process parameters on surface roughness and kerf width of HSLA steel. Taguchi’s L₁₈ orthogonal array is adopted to conduct the machining studies. MOORA method is used to evaluate the suitable combination of the LBM process parameters. The combined effect of machining performance measures is analysed using analysis of variance to identify the significance of the result. Consequently, the influence of the parameters on machining responses were explored. The surface morphology of the machined surface of the optimal set of parameters has been studied.

Abstract: Laser shock peening has been widely studied and pioneeringly applied in aerospace industry as a life-extension technology for structured mechanical components. However, in other promising fields such as nuclear power industry, little has been studied concerning such critical issues as long-distance transmission of the laser beam by optical fiber and optimized parameters of typically low pulse energy with micrometer-sized beam spots. In such scenario, the overlapping rate between adjacent small spots plays a critical role in obtaining homogenous residual stress and surface morphology. In this study, a three-dimensional finite element model in AISI 420 martensitic stainless steel has been developed to correlate the residual stress as well as surface morphology with varying overlapping rates. Multiple laser spots are loaded with VDLOAD user subroutine in Abaqus. The residual stress distribution is analyzed with respects of laser shocking and in-depth planes. And the surface morphology is evaluated in terms of depression depth as well as surface roughness. Combined results suggest that the overlapping rate of 61% as an optimized value, which can be used as a basis for future experimental studies and industrial applications.

Abstract: The structural thick plates were manufactured by varying the vacuum time at a constant argon gas flow rate and degree of vacuum during the Ruhrstahl Heraeus (RH) refining process. The inclusion and mechanical properties of the structural thick-plate specimens were evaluated according to vacuum time. The nitrogen in the converter had an effect after the RH process, and as the vacuum time of the RH process increased, the nitrogen content also increased. The nitrogen in the continuous casting (CC) decreased more than that in the converter, and as the vacuum time increased, the hydrogen decreased. Al₂O₃·CaO, MnS and Al₂O₃·MgO inclusions were observed in the structural thick plate. The average size of the oxides was (6.1 to 33.46) μm, while the average size of the Al-O-based inclusions was (4.26 - 6.3) μm. The mechanical properties, such as tensile strength, yield strength, and elongation, were affected by the vacuum time of the RH process with 10 min being the best. The micro-Vickers hardness showed dispersion regardless of the vacuum time of the RH process, which can be explained by the Weibull probability distribution. From the shape and scale parameters, although the specimen with the vacuum time of the RH process of 10 min showed a large dispersion in the micro-Vickers hardness, the characteristic value of 63.2 % was the best.

Abstract: In previous research problem statement occur in hardness to reach the thermal flux between surfaces during movement. The aim of the present investigation has been conducted to study the thermal behavior of ceramic Al₂O₃ (AL-99) coated on a low carbon steel type 1.0060 by using a thermal flame spray technique. The key methods used is microstructural characterization and comparing between experimental data record and numerical program.SEM showed that the Al₂O₃ coatings have a dense microstructure, lamellar morphology and complex of several phases. The XRD analysis of the coating after the spray showed a majority phase of α -Al₂O₃ rhombohedral structure and secondary phase of γ-Al₂O₃ orthorhombic structure. The experimental data recorded From wear indicate two step, first one corresponds to the phase of accommodation between surfaces (samples/ disc), the contact temperature gradually increases to a value Of 75 °C for both pairs, the second step , we could remark from experimental and numerical simulation, it reach 95°C for experimental test and 85 for numerical model.The important findings in tribological results showed that the temperature at the contact is related to the shear stress that will result from the increase of the heat flux. From these results it can be said that the measured temperature increases with the increase of the charge and converges with the contact time. The gap of temperature between experimental and numerical results is probably due to the parameter of microstructure, where in experimental porosities improve convection in the area, in contrast the numerical materials don't add this phenomena.

Abstract: Studies have shown that surface texture can improve lubrication state and reduce friction and wear. The cold pressing process of micro-units can prepare surface textures at low cost, in large quantities, and with high efficiency, but the micro-pillar array mold required for the cold pressing process is difficult to prepare. In this study, the influence of mask electrochemical processing parameters on the height and height uniformity of the micropillar array was studied by orthogonal experiment on the 42CrMo alloy steel. Four main factors are designed in the orthogonal experiment, namely voltage, duty cycle, frequency, and mask spacing, and each factor is set to three levels. The results of the range analysis show that: voltage and duty cycle are positively correlated with the height of the microcolumn, but negatively correlated with uniformity, and when the duty cycle is 50%, the uniformity of the microcolumn decreases sharply; The height and uniformity of the microcolumns increase with the increase of mask spacing. The height of the microcolumn is positively correlated with the frequency, and the uniformity of the microcolumn first increases and then decreases with the increase of frequency. Therefore, in order to meet the height and uniformity requirements at the same time, the grey correlation analysis method was used to obtain the optimal processing parameters: 35 V (voltage), 30% (duty cycle), 300 um (spacing), and 5 kHz (frequency). The average height of the microcolumns prepared by this parameter is 57.632 um and the microcolumn has excellent high uniformity.

Abstract: Alloy material testing for stable the properties of Vortex tube and corrosion resistance, this research for specially for fabrication of Vortex tube and also in future may supplier will ask the properties and testing evidence we are going to provide week wise testing schedule. Microbial Influenced Corrosion (MIC) is a type of corrosion that happened on a metal's surface under the seawater. MIC occurs due to the colonization of microorganism on the surface, these microorganisms may be fungus, bacteria or algae. In this paper the E. Coli bacteria are used to investigate the MIC on metal sample of vortex chamber. A metal sample of vortex tube which is stainless steel is coated with different coating such as alocit, rubber, epoxy, and graphene. The samples for vortex tube with different coating are tested to find out the best one which can resist MIC better than the others. There are different tests carried out; wet and dry test, atmospheric test. To find the corrosion progress the weight loss and corrosion rate is found in the sample material to apply vortex tube. The hardness of the coating is done to find the best one. The optical microscope is used to understand the corrosion progress in the metal surfaces and for the hardness test. The result analyzed shows that graphene is the best coating because of its excellent properties in resisting and preventing MIC corrosion of vortex tube is a non-conventional cooling device, having no moving parts which will produce cold air and hot air from the source of compressed air without effecting the environment when a high-pressure air is tangentially injected into the vortex chamber, a strong vortex flow will be created which will be split into two air streams. Beyond that, the improvement in energy separation is minor, and Vortex Tube performance begins to deteriorate as shock waves form outside the nozzle. Without any moving parts or chemical reactions, a vortex tube (VT) can generate hot and cold streams from a single pressurised room temperature fluid.

Abstract: M-type hexagonal ferrites have wide range of applications in magnetic recording media, microwave devices, micro electrochemical systems, high frequency devices, magneto-optical devices and many more. In present research, M-type strontium hexagonal ferrites doped with ‘magnesium’ having chemical composition (SrMg_xFe_12-xO₁₉) for x= 0.00, 0.05, 00.10, 0.15, 0.20, were synthesized to investigate the influence of rare earth metal doping on the structure and dielectric properties via sol-gel auto combustion technique. Molecular absorption/transmission, structural properties and dielectric response were investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and Dielectric measurements of ‘Mg’ doped strontium hexaferrites. X-ray diffraction analysis verified the magneto-plumbite structure. Crystal sizes were found in varying order for different concentrations of ‘Mg’ ranging from 12.357 to 15.375 nm. The FT-IR spectra exhibited higher frequency band (500–515.84 cm^-1) indicating tetrahedral site’s vibrations of metallic cations and lower frequency band (385.35–375.16 cm^-1) exhibiting octahedral sites due to metallic oxygen bond that confirmed the hexagonal structure. The resonance peaks were observed in dielectric constant, loss, tangent loss, AC conductivity, electric modulus and quality factor versus frequency graphs. The dielectric properties were found to be enhanced gradually by increasing concentration of magnesium. The best Q-factor was found for magnesium concentration (x=0.20). The dielectric parameters specify that these ferrite nanoparticles are good applicants for the higher frequency implementations.