Metallurgical and Materials Engineering (E-Journal)
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Mechanical characterization and fractography of 100 micron sized silicon carbide particles reinforced Al6061 alloy composites
Get PDFIn the current exploration, the impact of the 100 to 125 micron size addition of silicon carbide (SiC) on the mechanical performance of Al6061 alloy has been studied. The Al6061 alloy dispersed with 6, 9, and 12 wt.% of SiC particles were synthesized by a two-step stir cast route. Two-step addition of the preheated particles into the melt helps avoid the agglomeration of the particles, which further contributes to enhancing the properties of composites. The orchestrated composites were exposed to microstructural examines and mechanical properties evaluation. Microstructural portrayals of acquired examples were completed by SEM microscopy, EDS, and XRD patterns. The event of SiC particles were affirmed by the XRD patterns. The density of the Al6061-SiC composites was increased with the addition of high-density silicon carbide particles. The hardness, ultimate, and yield qualities of metal composites have been improved with the increase in the content of SiC support. The ductility of SiC reinforced composites decreased with hard ceramic particles' incorporation in the Al matrix alloy. Various fracture mechanisms were observed in the Al6061-SiC composites using SEM
Corrosion and Wear performances analysis of PVD CrMoN/Cr Coatings
Get PDFTools coated CrN based alloys are currently used in several industries for machining and manufacturing, but present severe wear, limiting their service life. Seeking an alternative, three CrMoN monolayers (~1 µm in thickness) coatings with varying in the Mo percentage content were elaborated using the RF magnetron co-sputtering method. These coatings were evaluated and compared with the alloy currently used (CrN) by electrochemical tests in NaCl solution (stationary and no stationary method) and sliding wear tests (ball-on-disc configuration) performed at room temperature. The results indicate that the samples coated with CrMoN presented better performance against wear and corrosion than the uncoated sample. Among the coatings, the labeled C1 (27 % Mo) showed the best corrosion resistance as it presents a positive corrosion potential Ecorr. However, the best wear resistance (lowest coefficient of friction) was shown by coating labeled C4 (33 % Mo). All of the tested specimens underwent abrasive wear in addition to adhesive wear
Solid particle erosion resistance of Al alloy and Al alloy-fly ash composite subjected to equal-channel angular pressing
Get PDFThis paper describes the influence of deformation by equal-channel angular pressing (ECAP) on the solid particle erosion resistance of the AlSi7Mg0.3 alloy and AlSi7Mg0.3 based composite material reinforced with the addition of 4 % of fly ash (FA) particles. Both, alloy and composite samples were produced using the compo-casting method. The samples have been subjected to ECAP in multiple passes with the rotation of samples around the vertical axis for the angle of 90 ° after each pass. Particles of silicon carbide (SiC) have been used as erodent while their impact angle was varied (30 ° and 90 °). Observed samples of AlSi7Mg0.3 alloy generally showed higher wear resistance at 90 ° angle where material fatigue predominates, than at a 30 ° angle where abrasion-related phenomena predominate. On the other hand, AlSi7Mg0.3 based composite material exhibited erosion wear at 30 ° angle less than at 90 ° angle after one ECAP pass. Evaluation of the erosion resistance has been made based on mass and volume loss. After two passes of ECAP, the matrix structure of the AlSi7Mg0.3 based composite material, as well as that of the AlSi7Mg0.3 alloy was improved from the aspect of erosion resistance
Comprehensive review of various corrosion behaviours on 316 stainless steel
Get PDFCorrosion is a destructive process that converts the pure metal into a chemically stabled form by hydroxide or sulphide and it is a slow process of destruction on the material by the chemical or electrochemical reaction in the environmental space. This kind of destruction has been typically produced from oxides or salt content on the material and it results in distinctive orange coloration. The classifications of corrosion act on atmospheric air and liquids as well as on contact of two solids. To resist the corrosion rate, stainless steel 316 has been chosen because of the presence of 2-3% molybdenum content and the presence of molybdenum plays a vital role in corrosion resistance. In this study, literature related to various works has been reviewed to explain the corrosion behaviour on cavitation, crevice, electrochemical, erosion, fatigue, galvanic, uniform, pitting, and stress corrosion which act on 316 stainless steel. In the present work, several coating processes and the additives, that have been added to SS 316 to enhance the outcomes according to various corrosion causes, are discussed
Prediction of the optimum asphalt content using artificial neural networks
Get PDFThe performance of the asphalt mix is significantly influenced by the optimum asphalt content (OAC). The asphalt content is responsible for coating the aggregate surface and filling the voids between the aggregate particles. Thus, the aggregate gradation has a significant influence on the required asphalt content. The Marshall design process is the most common method used for estimating the OAC, and this process is called the asphalt mix design. However, this method is time consuming, labor intensive, and its results are subjected to variations. Thus, this paper employs the artificial neural network (ANN) to estimate the OAC from the aggregate gradation for the two most common gradations used in asphalt mixes in Egypt (3D, 4C). Results show that the proposed ANN can predict the OAC with a coefficient of correlation of 0.98 and an average error of 0.026%. As a result, a new approach for the Marshall test can be adopted using results of the proposed ANN, and only three specimens, instead of fifteen, are prepared and tested for estimating the remaining parameters. This approach saves the time, effort, and resources required for estimating the OAC. Additionally, the ANN was validated with previously developed models, and the ANN shows promising results
Multi response optimization of Inconel 625 wire arc deposition for development of additive manufactured components using Grey relational analysis (GRA)
Get PDFThe paper investigates the multi response optimization of single bead deposition characteristics which affects the additive manufactured structures in later stages of multi layered depositions. Inconel 625 single beads were deposited using the cold metal transfer (CMT) based on Wire Arc Additive Manufacturing (WAAM). The bead width, bead height, penetration depth as well as microhardness of the fusion region are considered for the decision criteria models. Grey relational analysis (GRA) is used to solve the multi criteria optimization problem. Analysis of variance has been performed to quantify the parameters effects on grey relational grade (GRG). From the GRA, it is observed that at parameter setting of 110 Amps current, 0.4 mm/sec weld speed, and 4 mm standoff distance gives minimum bead width, minimum bead height, maximum penetration depth, and maximum microhardness
Corrosion rate and corrosion behaviour analysis of carbon steel pipe at constant condensed fluid
Get PDFThis study investigates the corrosion rate and corrosion behavior of carbon steel pipe at constant condensed fluid from a geothermal power plant. The corrosion rate of the steel was determined by weight loss analysis, whereas the corrosivity of the condensate fluids was measured by a multimeter Hach HQ40d. The morphology of the corrosion products formed was characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and x-ray diffraction (XRD) analysis. Results showed that the corrosion rate in the liquid part of the condensate fluids is constant during the immersion period when water quality parameters are constant. Meanwhile, the corrosion rate of low carbon steel pipe decreases though with the longer exposure period in the condensate fluid. The decrease of metal corrodibility identical to the lower corrosion rate at a longer exposure time due to the protective corrosion layer formed. The corrosion products during immersion tests identified in the corrosion test were uniform with iron oxide in the form of FeO(OH) and Fe2O3*H2O
Innovative processing routes in manufacturing of metal matrix composite materials
Get PDFMetal matrix composites (MMCs) belong to a group of modern materials owing to their excellent technological, mechanical, and physical properties such as excellent wear and corrosion resistance, high electrical and thermal conductivity, improved strength and hardness. Final properties of MMCs are affected equally by all steps of its manufacturing process. It is shown that by using adequate process parameters to obtain starting materials (reaching the specific size, shape, and reactivity) the control of volume fraction and distribution of reinforcements within the matrix can be achieved. For this purpose, mechanical alloying has been appointed as a good approach. MMCs can be produced using powder metallurgy, ingot metallurgy, and additive manufacturing techniques. Combining high-energy ball milling with these techniques enables the design of an innovative processing route for MMCs manufacturing. Mechanochemical process (achieved using high-energy ball milling) was employed in three manufacturing procedures: hot pressing, compocasting, and laser melting/sintering for obtaining of the suitable powder. These production routes for MMCs manufacturing were the subject of this work. The aim of MMCs design is to establish an optimal combination of production techniques merged into the cost-effective fabrication route for obtaining MMCs with required properties
Estimation of phosphorus distribution ratio at the end of blowing in BOF
Get PDFIn integrated steel plants, the removal of phosphorous normally takes place during the primary basic oxygen furnace (BOF) steelmaking process. Phosphorous is usually introduced to the integrated steelmaking process through blast furnace additions, such as iron ore, coke, sinter, and fluxes. Among the others parameters such as optimizing the charging system, oxygen supply system, oxygen lance parameters of the converter, the flux quality in combination with temperature process control can improve the BOF efficiency of Dephosphorization. Phosphorus partition ratio (LP) is usually used to evaluate the thermodynamic efficiency of the dephosphorization of slags with different compositions in steelmaking processes. However, this parameter is only useful in equilibrium conditions, and it is not accurate when used to evaluate slag efficiency in industrial processes. Because of this, the aim of this work was to study the phosphorus partition ratio estimated from the experimental results in real plant conditions of two different BOF steel plants and compare them with well-known published models. In the present study, data from two steel plants (further Plant A and Plant B) were evaluated applying Healy’s, Suito and Inoui’s, Zhang’s as well as Assis’s equations. The calculated values were compared against measured values
Monitoring the Blast furnace working state by a combination of innovative measurement techniques
Get PDFAt blast furnace B at Salzgitter Flachstahl a series of innovative measuring techniques are installed to monitor the processes at the blast furnace top, making this furnace one of the best equipped furnaces in Europe. These techniques comprise full 2D measurement of the temperature profile of the top gas shortly above the burden surface, 3D radar scan of the whole burden surface and online measurement of the dust concentration in the top gas. After more than 5 years’ experience with most of these techniques, they enable to better understand the complex chemical and physical interrelations occurring in the BF stack between the ascending process gas and the descending solid burden. A couple of examples of incidents that were monitored are presented in this article, including influences of charging programmes on top gas temperature profiles and influences of disturbed gas solids interaction on the BF working state. The new measuring techniques with tailor-made data processing enable the operators to gain a better picture of the processes currently occurring in the blast furnace, consequently supporting them in keeping the blast furnace operation as stable and efficient as possible