Selection Of Process Parameters Research Articles

Numerical simulation and surface morphology of laser cladding of nickel-based C276 alloy coatings on AerMet100 steel surface

In order to rationally characterize the laser cladding process and effectively predict the processing results, the temperature field and convective heat transfer at the solid-liquid interface were simulated using ANSYS software. Under the selected process parameters, C276 nickel alloy powder was clad on the surface of AerMet100 steel by laser cladding technology, and the microstructure of the cladding layer was observed to investigate the effects of laser power and scanning speed on the laser results. The effect of laser power and scanning speed on the laser results was investigated. The results show that the best coating performance is obtained when the laser power is 1400 W and the scanning speed is 14 mm/s. When the laser power is 1400 W, the scanning speed is increased from 12 mm/s to 16 mm/s, the dilution rate of the coating is increased from 0.385 to 0.423, and the height of the coating is decreased from 0.706 mm to 0.428 mm. When the scanning speed is 14 mm/s, the laser power is increased from 1000 W to 1600 W, the dilution rate of the coating is increased from 0.375 to 0.511, and the height of the coating is increased from 0.393 mm to 0.662 mm. The laser power has a large effect on the height, width, depth and dilution of the coating, while the scanning speed has a large effect on the average particle size of the coating.

Optimal parameter adjustment of catalytic combustion heaters for oil shale in-situ conversion of low calorific value gases

Oil shale resources are huge, and in order to develop and utilize them rationally, it is crucial to research heaters suitable for downhole in-situ conversion mining. Compared with the problems of short life and multi-stage energy utilization of downhole electric heaters, combustion heaters have advantages such as high thermal efficiency and low cost. The heater uses low calorific value industrial waste gas as the fuel for gas injection, which reduces carbon emissions and environmental pollution and saves gas injection costs. In this paper, we propose to apply catalytic combustion of low calorific value industrial waste gas to generate high temperature exhaust gas suitable for mining, and establish the relationship between gas injection flow rate, combustion chamber parameters and gas injection duration by mathematical methods. The effect of the downhole high-pressure environment on the catalytic combustion characteristics of low calorific gas was simulated and the formula for calculating the content of low calorific gas in the exhaust gas was modified. The results show that the determination of the relational equation solves the problem of excessive axial volume in the design process of downhole heaters. Under high pressure conditions downhole, the exhaust gas temperature and low calorific gas conversion rate are significantly improved. The catalyst ignition temperature ranged from 973 K to 1073 K. Increasing the downhole pressure to 5 MPa increased the conversion of low calorific value gas from 74.56% to 88.22%. The gas injection rate and calorific value range can be calculated by correcting the equation for the content of low calorific gas in the exhaust gas. The conclusion of the study provides a reference basis for the selection of catalytic combustion process parameters for low calorific industrial waste gas, and also provides an important theoretical basis for the construction of the downhole test prototype.

A pilot scale test study with theoretical justification of reaction mechanism for the recovery of chromium(VI) based on solvent extraction using novel centrifugal extractors

As a strategic resource and hazardous substance, the purification and recovery of chromium(VI) from the aqueous phase have attracted attention. In this study, the centrifugal extractor was used to treat the leach liquor of sodium roasting chromite on a pilot scale. The extraction performance and equilibrium distribution of chromium in countercurrent extraction were investigated. Meanwhile, the scrubbing effect of impurities was carefully studied, and the stripping and regeneration effects of the organic phase were tested. Under the selected process parameters, the pilot scale test results, including extraction efficiency of chromium, scrubbing efficiency of impurities, and regeneration performance of the organic phase, were excellent. The qualified (NH4)2Cr2O7 and Cr2O3 products were prepared using the strip liquor, and several physical properties of the products were tested. In addition, the molecular electrostatic potential surface maps, HOMO-LUMO orbitals, Fukui functions, and single point energy of the molecules involved were calculated by Quantum Chemistry. The molecular electrostatic potential analysis, frontiers molecular orbital analysis, Fukui function analysis and interaction energy analysis were applied to investigate the mechanism of separation of chromic acid from impurities in the extraction system.

Multiple criteria decision support analysis for manufacturing process parameters selection of metallic bipolar plates for polymer electrolyte membrane fuel cells

The multi-criteria decision-making method, along with experimental and finite-element (FE) methods, was employed to determine the optimal process parameter values for rubber pad forming of metallic bipolar plates. To achieve this aim, the rubber pad forming process was modeled by FE software, and the results were validated by conducting experimental tests. Three significant rubber pad forming parameters—punch force, hardness, and the thickness of the rubber layer—were considered as input variables. A full-factorial design involving 27 experiments was used to assess the alternatives. Filling percentage, thinning ratio, and stress were considered as distinct evaluation criteria. To solve the multi-criteria decision-making problem, a hybrid approach was used to weigh the alternatives. According to the results, the applied method was capable of selecting the optimal values of process parameters while considering different criteria simultaneously. The results demonstrated that a punch force of 50 kN, rubber hardness of 55 Shore A, and rubber thickness of 3.5 mm were the best processing conditions. For these parameters, the filling percentage, thinning ratio, and stress were 97.6%, 28.5%, and 1005 MPa, respectively.

Numerical Simulation of Temperature Characteristics and Graphitization Mechanism of Diamond in Laser Powder Bed Fusion.

Thermal damage to diamonds is a major limitation in laser powder bed fusion (LPBF) processing of metal matrix diamond composites. In this paper, a numerical simulation model was established to describe the thermal effect of the Diamond-CuSn10 composite on the LPBF process. The simulation results show that the temperature of the diamond presents a double-peak structure, and the double-peak temperature curve shape can be modulated by modifying the laser scanning offset and the size of the diamond powder. And it suggests that the heat of the diamond mainly comes from the transfer of the molten pool. Then, combined with the experimental phenomenon, the mechanism of diamond graphitization in the LPBF process is analyzed. It indicates that since the surface defects of the diamond inhibit the heat conduction of the diamond, the temperature accumulates on the surface, leading to the graphitization of the diamond. Finally, based on this model, the potential of Ti-coated diamonds to prevent and reduce thermal damage in the LPBF process has been extensively studied. It is found that a Ti coating with low thermal conductivity can effectively reduce diamond temperature and improve diamond graphitization resistance. This study can provide a good method and basis for the preliminary selection of LPBF process parameters and the understanding of the graphitization mechanism of diamond tools.

Selection of Optimal Process Parameters to Obtain Defect-Free Builds in IN718 Made by Laser Powder Bed Fusion

Selection of Optimal Process Parameters to Obtain Defect-Free Builds in IN718 Made by Laser Powder Bed Fusion

Effect of internal defects on tensile strength in SLM additively-manufactured aluminum alloys by simulation

This research investigates the effect of internal defects on the tensile strength of Selective Laser Melting (SLM) additively-manufactured aluminum alloy (AlSi10Mg) test parts used for civil aircraft light weight design. A Finite Element Analysis (FEA) model containing internal defects was established by combining test data and the stress concentration factor comparison method. The effect of variation in the number, location and shape of defects on the finite element results was analyzed. Its results show that it is reasonable to use spherical defect modeling. The finite element modeling and analysis methods are also applied to the study of the effect of internal defects on tensile strength in additive manufacturing of other metallic materials. According to the FEA results of single defects at different scales, the formula for calculating the weakening degree of tensile strength applicable to the defective area of less than 15% was established. The result of the procedure is reliable and conservative. This research results can guide the selection of process parameters for the additive manufacturing of aluminum alloys. Further, the research results can promote the application of metal additive manufacturing in designing light-weight civil aircraft structures.

An integrated modelling and optimization approach for the selection of process parameters for variable power consumption machining processes

An integrated modelling and optimization approach for the selection of process parameters for variable power consumption machining processes

Characterization and modelling of the crystallization behavior of PEEK for polymer processing techniques

This study examines the crystallization behavior of high-performance thermoplastics under both isothermal and non-isothermal conditions. The accurate prediction of the crystallization kinetics in conjunction with process simulation tools can create new methods for defining the key process parameters in various polymer processing techniques. By simulating the thermal history of the materials, optimal process parameters can be assigned at specific time points, resulting in a more homogeneous process and improved material properties, while avoiding costly and time-consuming trial-and-error experimentation or post-processing. Here, flash differential scanning calorimetry (DSC) was used to capture the rapid crystallization of Luvocom 3F PEEK 9581 NT, and various isothermal and non-isothermal models were applied to mimic its crystallization behavior, highlighting the differential form of the dual Nakamura model as the most suitable option. To accurately predict the absolute crystallinity, the maximum achievable enthalpy was introduced in the model, and weight factors were assigned to the primary and secondary crystallization mechanisms. The differential form of the model is suitable for efficient implementation in process simulation tools, because it is independent of the total crystallization time. This research has the potential to significantly improve the selection of proper process parameters in complex polymer processing techniques, e.g., material extrusion.

Optimization of 3D Printing Parameters for Enhanced Surface Quality and Wear Resistance.

In recent years, there has been a growing interest in the field of 3D printing technology. Among the various technologies available, fused deposition modeling (FDM) has emerged as the most popular and widely used method. However, achieving optimal results with FDM presents a significant challenge due to the selection of appropriate process parameters. Therefore, the objective of this research was to investigate the impact of process parameters on the tribological and frictional behavior of acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) 3D-printed parts. The design of experiments (DOE) technique was used considering the input design parameters (infill percentage and layer thickness) as variables. The friction coefficient values and the wear were determined by experimental testing of the polymers on a universal tribometer employing plane friction coupling. Multi-response optimization methodology and analysis of variance (ANOVA) were used to highlight the dependency between the coefficient of friction, surface roughness parameters, and wear on the process parameters. The optimization analysis revealed that the optimal 3D printing input parameters for achieving the minimum coefficient of friction and linear wear were found to be an infill percentage of 50% and layer thickness of 0.1 mm (for ABS material), and an infill percentage of 50%, layer thickness of 0.15 mm (for PLA material). The suggested optimization methodology (which involves minimizing the coefficient of friction and cumulative linear wear) through the optimized parameter obtained provides the opportunity to select the most favorable design conditions contributing to a more sustainable approach to manufacturing by reducing overall material consumption.

Influence of wire electrical discharge conditioning on the grinding performance of metal-bonded diamond grinding tools

Wire Electrical Discharge Conditioning (WEDC) is an efficient non-conventional method for conditioning metal, resin, and hybrid bonded super-abrasive grinding tools. Since the diamond and CBN grains are not affected directly by the WEDC and only the electrically conductive bond material is eroded by the process, high grain protrusions are achievable. Therefore, unlike the common mechanical conditioning methods using WEDC, the microtopography of the grinding tool can be influenced by the process parameters, directly affecting the grinding efficiency. However, the selection of WEDC process parameters is influenced by the specifications of the grinding tool, particularly the grain size and concentration. This study aims to investigate the effects of WEDC parameters and strategies on the microtopography and material removal rate of metal-bonded grinding tools, considering different grain sizes and concentrations. Additionally, the correlation between the microtopography of grinding tools conditioned by the WEDC process and their grinding efficiency was investigated by analyzing tool wear, grinding forces, and surface roughness of tungsten carbide workpieces. The results indicate that the material removal rate of the WEDC process decreases as the grain size and concentration of metal-bonded diamond grinding tools increase. Furthermore, it was observed that employing high spark energy parameters reduces the grain protrusion of grinding wheels with small grain sizes. However, the utilization of high-energy sparks is necessary to create larger spark gaps and achieve a higher material removal rate.

Influence of Selected Parameters on the Product Yields of Broom Weed (Sida acuta) Pyrolysis

Biomass feedstocks have been utilized for the commercial production of a wide range of fuels and chemicals through the pyrolysis process. Broom weed is abundant but it has not been widely used in Nigeria as a means of useful fuel and chemical thereby constituting an environmental menace. This study aimed to determine the effects of selected process parameters on the product yields during the pyrolysis of broom weed in a fixed bed reactor. Broom weed was obtained at the premises of the National Centre for Agricultural Mechanization, Ilorin, Kwara State, Nigeria. 0.1kg of a dried sample of broom weed was loaded into a steel retort, and the retort interior was rendered airtight. The retort was then placed into the furnace chamber and was pyrolysed at 300oC between 10 - 30 minutes at 5 minutes intervals. This was repeated for temperatures of 350, 400, 450, and 500 oC, and in each case, the quantities of char, bio-oil, and gas produced were determined. The average minimum values of the product yielded char, bio-oil, and gas for broom weed were 62.43 wt% at 500 ⁰C, 4.34 wt% at 300 ⁰C and 12.62 wt% at 300 ⁰C, respectively, while the maximum values were 83.37 wt% at 300 ⁰C, 8.80 wt% at 450 ⁰C and 30.96 wt% at 500 ⁰C, respectively. This study showed that pyrolysis of broom weed can serve as a renewable source of energy rather than constituting an environmental menace.

Plastic deformation behavior and strengthening mechanism of SLM 316L reinforced by micro-TiC particles

In this work, the integrated study on the microstructure evolution, plastic deformation behavior, and strengthening mechanism of Selective Laser Melting (SLM) 316L austenitic stainless steel (ASS) reinforced with micro-TiC particles was investigated. The results indicated that there were lots of small angle grain boundaries in SLM 316L ASS, and the high dislocation density and component segregation of the cellular dislocation structure resulted in a good combination of high strength and good elongation in performance. The tensile strength, yield strength, and elongation of SLM 316L ASS were 682 MPa, 571 MPa, and 49.9%, respectively. The addition of TiC reinforced particles induced microstructure evolution, including grain refinement, reduction of epitaxial columnar dendrites, reduction of low angle grain boundary (LAGB) ratio and increase of Σ3 (60°/<111>) twin boundaries. Through the effects of grain refinement strengthening, Orowan strengthening, and dislocation strengthening, SLM 316L-2TiC showed a higher tensile strength of 1021 MPa and higher yield strength of 809 MPa, while maintaining an elongation of 30.8% due to the suppression of plasticity by twinning induced plasticity (TWIP) effect. Although nano-reinforced particles were commonly used to improve mechanical properties, in our work, we chose to add micrometer-sized TiC particles, and the strength of the SLM 316L-2TiC metallic matrix composites (MMCs) exceeded the previous reports of adding nanoparticles. The reason was that the small contact angle between TiC and 316L provides good wettability between the particles and the melt, and the selection of laser processing parameters ensures good bonding between TiC particles and the substrate.

Effects of process parameters and scan strategy on the microstructure and density of stainless steel 316 L produced via laser powder bed fusion

The ability to produce reliable and reproducible components from 316 L using additive manufacturing is crucial to serve the need for customization, on-demand manufacturing and reduced lead times for various industries. Laser powder bed fusion is becoming widely accepted as a versatile additive manufacturing technique capable of producing near defect-free components with tailored microstructures and mechanical properties. However, despite the recent progress in process parameter selection and optimization, even a small change in any of the laser parameters, equipment and feedstock powder characteristics can influence the microstructure and subsequently the mechanical properties of the fabricated parts. The purpose of this work is to tackle the process optimization challenge through, a full factorial design of experiments approach, to systematically assess the widely adopted energy density factor to evaluate the density of the final component. A statistical approach was also followed to evaluate potential plastic anisotropy in different samples produced with various energy densities and scan strategies. Density measurements indicated that beyond laser power and scan speed, the interaction effects of the aforementioned parameters with the layer thickness and the powder size distribution have a significant effect on the sample. Microstructural features such as melt pools, grains and crystallographic texture were characterized against a range of volumetric energy densities and scan strategies represented by different angles of rotation between successive layers. Smaller angles of rotation per layer were found to decrease texture anisotropy and suppress the formation of keyhole porosity in finer and more homogenous microstructures. The assessment of plastic anisotropy in the produced samples was evaluated using microhardness measurements on all three orthogonal planes of the samples. The hierarchical microstructure of laser powder bed fusion materials induces several strengthening mechanisms, that can simultaneously be activated depending on the loading scenario, location and plane.

Electromagnetic shielding properties of LPBF produced Fe2.9wt.%Si alloy

Ferromagnetic materials are used in various applications such as rotating electrical machines, wind turbines, electromagnetic shielding, transformers, and electromagnets. Compared to hard magnetic materials, their hysteresis cycles are featured by low values of coercive magnetic field and high permeability. The application of additive manufacturing to ferromagnetic materials is gaining more and more attraction. Indeed, thanks to a wider geometrical freedom, new topological optimized shapes for stator/rotor shapes can be addressed to enhance electric machines performances. However, the properties of the laser powder bed fusion (LPBF) processed alloy compared to conventionally produced counterpart must be still addressed. Accordingly, this paper presents for the first time the use of the LPBF for the manufacturing of Fe2.9wt.%Si electromagnetic shields. The process parameter selection material microstructure and the magnetic shielding factor are characterized.

Influence of rotational tool speed on metallurgical characterization of friction stir welded joint of AZ91D and AA2024

This study investigated the dissimilar friction stir welding (FSW) of AA2024 and AZ91D and aimed to explore the effect of rotation tool speed (RTS) on welding quality and the formation of intermetallic compounds (IMCs) in the welded region. The optimal welding parameters for achieving a sound weld were determined to be a traverse speed (TS) of 35 mm/min and an RTS of 700 r/min. The presence of two specific intermetallic phases, Al3Mg2 and Al12Mg17, was observed in all joints, with Al12Mg17 showing a tendency to migrate toward the weld surface adjacent to the AZ91D plate, possibly resulting in constitutional liquation during solidification. The results revealed that the morphological characteristics and input heat significantly influenced the formation of IMCs. Moreover, the study highlighted that improper selection of processing parameters, particularly using lower RTS and TS, led to the development of dense layers of IMCs, such as Al12Mg17 and Mg + Al12Mg17, within the stir zone (SZ). Consequently, this led to a decrease in the ultimate tensile strength (UTS) of the FSWed joints. The highest UTS value of 147.26 MPa was achieved with an RTS of 700 r/min and a TS of 35 mm/min, while the lowest UTS value of 113.47 MPa was observed at an RTS of 500 r/min and a TS of 35 mm/min.

Freeze-dried nanocrystal dispersion of novel deuterated pyrazoloquinolinone ligand (DK-I-56-1): Process parameters and lyoprotectant selection through the stability study

Recently, nanocrystal dispersions have been considered as a promising formulation strategy to improve the bioavailability of the deuterated pyrazoloquinolinone ligand DK-I-56-1 (7‑methoxy-2-(4‑methoxy-d3-phenyl)-2,5-dihydro-3H-pyrazolo[4,3-c]quinolin-3-one). In the current study, the freeze-drying process (formulation and process parameters) was investigated to improve the storage stability of the previously developed formulation. Different combinations of lyoprotectant (sucrose or trehalose) and bulking agent (mannitol) were varied while formulations were freeze-dried under two conditions (primary drying at -10 or -45 °C). The obtained lyophilizates were characterized in terms of particle size, solid state properties and morphology, while the interactions within the samples were analyzed by Fourier transform infrared spectroscopy. In the preliminary study, three formulations were selected based on the high redispersibility index values (around 95%). The temperature of primary drying had no significant effect on particle size, but stability during storage was impaired for samples dried at -10 °C. Samples dried at lower temperature were more homogeneous and remained stable for three months. It was found that the optimal ratio of sucrose or trehalose to mannitol was 3:2 at a total concentration of 10% to achieve the best stability (particle size < 1.0 μm, polydispersity index < 0.250). The amorphous state of lyoprotectants probably provided a high degree of interaction with nanocrystals, while the crystalline mannitol provided an elegant cake structure. Sucrose was superior to trehalose in maintaining particle size during freeze-drying, while trehalose was more effective in keeping particle size within limits during storage. In conclusion, results demonstrated that the appropriate combination of sucrose/trehalose and mannitol together with the appropriate selection of lyophilization process parameters could yield nanocrystals with satisfactory stability.

Experimental and Numerical Investigation of a Solidification-Based Aluminum-Cooled Finger Refinement Process From Micro to Macro-Scale

The interest in ultra-pure metals is steadily growing due to the increasing demand for these materials in modern technology. To be able to meet the increasing demand in the future, it is necessary to implement more efficient and productive processes. As a fractional crystallization method in this application area, the cooled finger method exhibits higher productivity and lower energy requirements when compared to industry well-established methods like zone melting. In this study, the mechanisms and relevant phenomena crucial for a successful implementation of a cooled finger process were investigated using a multidisciplinary approach. With carefully selected process parameters, we present here an experimental setup with a purification potential of approximately 80 pct. Additional micro- and macro-scale simulations demonstrate that the process is sensitive to parameters such as rotation rate, cooling rate, and temperature gradient within the melt, which explains the difficulty in optimizing this process in practice. An analysis and description of various phenomena that characterize the behavior of the cooled finger process are presented within this multi-scale approach. As a result, these approaches can also be transferred to the description of processes for other metals, opening application areas outside of the purification of aluminum.

Tensile, microhardness and microstructural characteristics of friction stir welded/processed AA7075 alloy: A review

The aircraftand automobile industries have a great demand for aluminium alloys such as AA7075 due to their excellent features. However, it is difficult to join AA7075 using electric arc welding process. Therefore, a novel green welding process namely, friction stir welding (FSW), could be employed for fabricating the joints without any defects. FSW, is a proven solid state joining process capable to join several key engineering materials such as aluminium, magnesium, copper, titanium, and several steel grades. In this review study, the FSW characteristics of a well-known aircraft alloy AA7075 is presented systematically. Weld/processed characteristics such as microhardness, ultimate tensile strength, and microstructural are discussed. It is observed that, FSW process could yield better joints without any defects unlike in traditional welding processes. By proper selection of tool and process parameters will result in improvement of weld efficiency of AA7075 alloy. Fine grained microstructure resulting in better hardness and strength of AA7075 joints. However, there is lack of studies that needs to be carried out on integration of the digital tools such as artificial intelligence (AI) and machine learning (ML) is necessary to reduce FSW time.

Magnetic stimulation of chemical reactions in coal

Purpose. To identify a mechanism in terms of which a signal of weak magnetic field is transformed into response of some components of nanostructure of a carbonaceous matter with further formation of chemical bonds. Methodology. Physical and mathematical modelling procedures of elementary chemical acts have been applied. Regularities of quantum mechanics and dynamics of chemical bonds were also used in addition to a magnetic isotope theory, a diffusion theory of recombination of radical pairs taking into consideration triplet-singlet transit, and nuclear-spin selectivity of chemical reactions. Findings. The physical mechanism of the magnetic scenario of interradial reactions is considered from the viewpoint of their energy stimulation through magnetic fields, i.e. the idea has been implemented according to which the number of radical pairs, able to be recombined into stable molecules, increases significantly if the weak magnetic field exercises certain influence. In addition to stimulation of interradial reactions, the magnetic field impact on organic coal mass-radicals results in stabilization of carbonaceous structures with regular atomic arrangement (being two-dimensional matrices, chains etc.) and their increase. Originality. A physical model of structural and phase changes in coal, depending upon the effect by external weak magnetic field, has been developed. It has been shown that the weak magnetic field signal, being incomparably smaller energetically to compare with the energy of thermal molecular motion, can initiate triplet-singlet transitions, i. e. transform radicals into reactive state. A mechanism has been proposed to form chemical bonds between movable radicals and non-complete bonds of atoms at the surfaces of solid phases of carbonaceous matter. Practical value. Implementation of the obtained results, concerning magnetic coal processing, may be connected with the development of a new procedure to avoid explosive conditions in coal seams. Progress in the field of magnetic processing should involve studies concerning calculation and selection of coal processing parameters (i.e. magnetic field density, frequency, energy, and a processing period) to control efficiently the chemical reactions in the carbonaceous matter. A substantiation degree of coal processing will influence greatly both efficiency of chemical processes and expediency of practical use of the results.