Centrifugal Casting Process Research Articles

Fabrication and mechanical properties of functionally graded materials: A review

Despite many studies in the field of materials, conventional materials such as alloys and composites could not cope with the customers' tailored-made requirements; in those cases, functionally graded materials with controlled constituent's gradation to develop the required properties in the material. The review paper demonstrates the research work carried out in functionally graded materials. The present review mainly focuses on processing techniques with critical parameters of powder metallurgy, spark plasma sintering, centrifugal casting, Additive manufacturing, and Electrophoretic process.

Effect of feed sprue size on porosity defects in Platinum 950 centrifugal investment casting via numerical modelling

The centrifugal investment casting process is typically used in the jewelry manufacturing industry. However, porosity defects are often found in jewelry castings made by this process. Porosity on the casting surface is a major concern for jewelry manufacturers as the defect leads to significant yield losses during the repair work. Improper feed sprue design is one of the major causes of porosity defects. The purpose of this work is to study the effect of feed sprue size on porosity defects in Platinum 950 jewelry made by the centrifugal investment casting process. Two feed sprue sizes were experimented in this study. FLOW-3D CAST software was employed for the casting process simulation. Simulation results were analysed together with experimental results quantified by an image analysis technique. The results show that the larger feed sprue provides castings with less porosity compared to the smaller feed sprue.

Mechanical Properties of White Metal on SCM440 Alloy Steel by Laser Cladding Treatment

The bearing is a machine element that plays an important role in rotating the shaft of a machine while supporting its weight and load. Numerous bearings have been developed to improve durability and life, depending on the functions and operating conditions in which they are desired. White metal is one of method to improve durability that is soft and bonded to the inner surface of the bearing to protect the bearing shaft. Currently, the centrifugal casting process is used as a white metal lamination method, but it involves problems such as long processing times, high defect rates and harmful health effects. In this paper, a laser cladding treatment is applied to bond powdered white metal to SCM440 alloy steel, which is used as bearing material in terms of replacing the risks of a centrifugal process. In order to understand whether laser cladding is a suitable process, this paper compares the mechanical properties of white metal produced on SCM440 alloy steel by centrifugal casting and the laser cladding process. The laser power, powder feed rate and laser head speed factors are varied to understand the mechanical properties and measure the hardness using micro Vickers and conduct field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and friction testing to understand the mechanical properties and surface characteristics. Based on the results, the hardness values of the cladding (white metal) layer ranged between 24 and 26 HV in both the centrifugal casting and laser cladding methods. However, the hardness of the white metal produced by laser cladding at about a depth of 0.1 mm rose rapidly in the cladding process, forming a heat-affected zone (HAZ) with an average hardness value of 200 HV at a laser power of 1.1 kW, 325 HV at 1.3 kW and 430 HV at 1.5 kW. The surface friction testing results revealed no significant differences in the friction coefficient between the centrifugal casting and laser cladding methods, which allows the assumption that the processing method does not significantly influence the friction coefficient.

Characterization of Aluminum Alloy–Silicon Carbide Functionally Graded Materials Developed by Centrifugal Casting Process

The continuous development of modern industries rises the necessity for functionally graded materials. This research starts from the consideration that the incorporation of SiC particles in the molten aluminum alloy can be difficult due to the very low wettability of SiC particles. In order to increase their wettability, SiC particles were covered with a layer of metallic copper. The incorporation of SiC particles into the aluminum alloy mass was performed by centrifugal casting. The secondary hypoeutectic Al-Si alloy used in this study was elaborated within the crucible of a resistors heated furnace. The metallic coating of SiC particles, in addition to the effect of increasing their wettability by molten metal, also has a role in preventing the formation of aluminum carbide in case of heating above 700 °C. A great amount of attention was paid to the parameters used during the centrifugal casting process. The results showed that adjusting the proportion of SiC particles within the composite allows us to obtain values of the thermal expansion coefficient within previously established limits. The present work demonstrates that the coating of SiC particles covered with a thin layer of metallic Cu creates the conditions to easily incorporate them into the molten Al mass, thus obtaining FGMs with controlled properties.

Effect of centrifugal casting temperature on the microstructure and properties of ZTAP/HCCI matrix composites

In the centrifugal casting process, the casting temperature parameters affected the microstructure characteristics, and the performance of the materials was greatly significant. ZTA (ZrO2 reinforced Al2O3) particles reinforced HCCI (High chromium cast iron) matrix composites with honeycomb structure were obtained by centrifugal casting. With the increased casting temperature (1450 °C, 1500 °C, 1550 °C, and 1600 °C), the austenite equivalent diameter size was 43.5 μm, 34.8 μm, 33.1 μm, 22.3 μm respective in the compound area and 58.3 μm, 63.1 μm, 65.2 μm, 71.5 μm respective in substrate area. The average size of eutectic carbides in the compound area decreased from 5.7 μm to 2.5 μm with the casting temperature increased. Meanwhile, the lattice constants of austenite and carbide increased with the increased temperature. The hardness of the composites increased by 4 ∼ 6HRC with a change in casting temperature. The results of three-body abrasive wear under high-stress static load conditions showed that the wear volume loss of the composites reduced with the temperature increased and the wear resistance was 1.4 times at 1600 °C than that at 1450 °C.

Microstructural evolution and enhanced mechanical properties of Mg–Gd–Y–Zn–Zr alloy via centrifugal casting, ring-rolling and aging

A ring-shaped Mg–8.5Gd–4Y–1Zn–0.4Zr (wt%) alloy was manufactured via centrifugal casting and ring-rolling process. The effects of accumulative ring-rolling reduction amount on the microstructure, texture, and tensile properties of the alloy were investigated. The results indicate that the microstructure of centrifugal cast alloy consists of equiaxed grains and network-like eutectic structure present at grain boundaries. The ring-rolled alloy exhibits a characteristic bimodal microstructure composed of fine dynamic recrystallized (DRXed) grains with weak basal texture and coarse un-DRXed grains with strong basal texture, along with the presence of LPSO phase. With increasing amount of accumulative ring-rolling reduction, the coarse un-DRXed grains are refined via the formation of increasing amount of fine DRXed grains. Meanwhile, the dynamic precipitation of Mg 5 RE phase occurs, generating a dispersion strengthening effect. A superior combination of strength and ductility is achieved in the ring-rolled alloy after an accumulative rolling reduction of 80%. The tensile strength of this ring-rolled alloy after peak aging is further enhanced, reaching 511 MPa, while keeping a reasonable ductility. The salient strengthening mechanisms identified include the grain boundary strengthening of fine DRXed grains, dispersion strengthening of dynamic precipitated Mg 5 RE phase, short fiber strengthening of LPSO lamellae/rods, and precipitation strengthening of nano-sized prismatic β′ precipitates and basal γ′ precipitates.

Effects of Ti6Al4V Surfaces Manufactured through Precision Centrifugal Casting and Modified by Calcium and Phosphorus Ion Implantation on Human Osteoblasts

(1) In order to enable a more widespread use of uncemented titanium-based endoprostheses to replace cobalt-containing cemented endoprostheses for joint replacement, it is essential to achieve optimal osseointegrative properties and develop economic fabrication processes while retaining the highest biomedical quality of titanium materials. One approach is the usage of an optimized form of Ti6Al4V-precision casting for manufacturing. Besides the chemical and physical properties, it is necessary to investigate possible biological influences in order to test whether the new manufacturing process is equivalent to conventional methods. (2) Methods: Primary human osteoblasts were seeded on discs, which were produced by a novel Ti6Al4V centrifugal-casting process in comparison with standard machined discs of the same titanium alloy. In a second step, the surfaces were modified by calcium or phosphorus ion beam implantation. In vitro, we analyzed the effects on proliferation, differentiation, and apoptotic processes. (3) Results: SEM analysis of cells seeded on the surfaces showed no obvious differences between the reference material and the cast material with or without ion implantation. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) proliferation assay also did not reveal any significant differences. Additionally, the osteogenic differentiation process tested by quantitative polymerase chain reactions (PCR), Alizarin red S assay, and C-terminal collagen type I propeptide (CICP) Elisa was not significantly modified. No signs of induced apoptosis were observed. (4) Conclusions: In this study, we could show that the newly developed process of centrifugal casting generated a material with comparable surface features to standard machined Ti6Al4V material. In terms of biological impact on primary human osteoblasts, no significant differences were recognized. Additional Ca- or P-ion implantation did not improve or impair these characteristics in the dosages applied. These findings indicate that spin casting of Ti6Al4V may represent an interesting alternative to the production of geometrically complex orthopedic implants.

Characterization of Graphite-Reinforced LM30-Aluminium Matrix Composite Processed through Gravity and Vertical Centrifugal Casting Processes

This paper discusses the fabrication of graphite-reinforced aluminium LM30 (A390) matrix composite through gravity die casting and vertical centrifugal casting processes (VCC). The microstructures and the hardness of the cast specimen were characterized and presented here. The functionally graded composite (FGCs) processed through VCC showed the gradual transition of graphite and primary silicon from outer region to core region in microstructures. This was based on the gravity difference amongst the reinforcement and matrix during centrifugal casting. FGC is one of the potential engineering materials and has many applications in engineering industry. The microstructure of the gravity cast sample showed no gradual transitions but showed the uniform distribution of graphite reinforcement. The hardness of gravity cast samples showed a maximum of 130 HB. The hardness of FGC was measured from the outer periphery to the inner periphery. The results showed that the inner periphery had low hardness than that of inner periphery. Graphite particles reduced the hardness and increased the lubricating property of the composite. Gravity cast specimen showed greater hardness than that of VCC processed FGCs. Graphite particles had associated mostly with the primary silicon particles. Though the primary silicon particles are at inner, the graphite particles reduced the hardness.

Analisa Pengukuran Cylinder Liner dan Piston pada Overhoul Diesel Engine

In addition to knowing the various types of machining components that exist, operators are required to know the maintenance and be able to measure each component so that the diesel engine's performance does not experience problems that result in decreased engine performance. Meanwhile, the supporting components of the diesel engine are like cylinder liners, because the cylinder liner components determine the volume of the cylinder and the performance of the diesel engine. The shape of the cylinder liner is like a tube where the manufacturing process uses a horizontal centrifugal casting process. Horizontal Centrifugal casting process is a casting process for making cylinder liners by pouring molten metal into a rotating mold. Implementation of Top Overhaul on diesel engines is carried out by opening the cylinder head or the top of the engine. The parts examined include the rocker arm, inlet and exhaust valves, injectors, air starting valves and push rods. Top Overhaul is carried out when the working hours of the diesel engine have worked with around 6,000 hours of work. Major Overhaul maintenance, which includes inspection, maintenance and inspection carried out on all Top Overhaul works and on the piston, connecting rod, piston ring, seated metal and road metal. Major Overhaul maintenance is carried out when the diesel engine has 12,000 working hours according to the Diesel Engine Intruction Book. In the cylinder liner often occurs damage or looseness which is commonly referred to as abrasion, erosion and corrosion. Because of that the cylinder liner requires maintenance and measurement using an inside micrometer tool. From the results of the measurements and maintenance on the cylinder liner, the calculation of the consistency, taper and wear was obtained, to find out the specifications or exceed the limits specified in the Main Engine Intruction Book on the ship.

Investigation of Microstructure and Mechanical & Electrochemical Behaviors of Martensitic Stainless Steel (MSS) and Alloyed White Cast Iron (WCI) Rolls Fabricated by a Centrifugal Casting

The present study focuses on the production of two kinds of composite rolls by the horizontal centrifugal casting process and the investigation of the chemical composition, microstructure, mechanical & electrochemical behaviors of the products. Alloyed white cast iron (WCI) and martensitic stainless steel (MSS) were successfully produced with this method. The chemical compositions of the produced materials were examined by X-Ray Fluorescence Analysis (XRF). The microstructural properties were examined using an optical microscope (OM). These produced rolls are developed for grinding purposes. The rolls used in the grinding process must also have higher hardness values, so Vickers hardness measurements are performed on the WCI and MSS alloys. Moreover, produced rolls intended to work in corrosive working environment as well. Due to these requirements, the corrosion resistance plays important role for these rolls. Corrosion behavior of casted samples were investigated via potentiodynamic polarization measurements.

Distribution of Simulating Reinforced Dispersed Particles Across Metal Rods

The paper outlines the process of developing a computer model to predict particle distribution during centrifugal casting using the ANSYS FLUENT 16.0 software module. There are several mathematical models developed to predict the volume distribution of particles. The majority of the models is based on a steady state assumption: these are models describing criteria for repelling particles by a propagating crystallization front and the models calculating critical velocities of absorbing particles by growing dendritic crystals. Some models are aimed at describing the dynamic state of the system or at determining the criterion of capturing non-metallic inclusions by hardening front during centrifugal metal casting. The description of the process for deriving the model, the schematic diagram and geometry, is given. The model preprocessor considers the following phenomena: the two-phase flow, the energy equation, the laminar flow, the introduction of discrete phases (hardening particles), and the melting/crystallizing phenomena. The model considers the interaction between two liquid phases: air and steel melt. The interphase interaction is described using the surface tension equation. Steel grade 12Х18Н10T is used as the base metal. The particles of tungsten carbide, boron carbide and yttrium oxide are introduced as dispersion. The physics and chemical parameters of these substances are considered by the simulator. The process of simulating particle distribution during centrifugal casting using the computational cluster is described using Skif-Ural, which is one of the top 500 most powerful computers in the world. In addition to graphical display, the simulation generates data for coordinates of each particle with the time increment of 0.00001 sec which allows predicting the exact location of each particle at each moment of casting. The results show that the process of centrifugal casting involving introduction of dispersed particles allows obtaining dispersed and hardened metal materials having forecasted distribution of heat-resisting particles.

Investigations on the Melt Flow Behavior and Microstructure of A390 Alloy During Vertical Centrifugal Casting Process: CFD Simulation and Experiments

In this study, vertical centrifugal casting process is used for the fabrication of functionally graded A390 alloy hollow cylinder and Mg & Sr-included A390 alloy hollow cylinder. The commercial CFD software FLOW3D™ is used to obtain the optimum rotational speed for making an optimized hollow cylinder in a vertical centrifugal casting machine. The optimum rotational speed obtained is 1300 rpm. This rotational speed is used in the experiments to obtain hollow cylinders of optimized thickness for (a) A390 alloy (b) by adding various weight percentages of Mg and Sr in A390 alloy. The optical microstructures obtained at various radial locations are presented for centrifugally cast A390 alloy. The effect of individual addition of Mg & Sr into A390 alloy on the microstructures at various locations along the radial direction of centrifugally cast cylinder is discussed in detail.

USING GEOPOLYMER COMPOSITES FOR HEAT AND CORROSION RESISTANT PIPES

This research studied the use of carbon fiber reinforced geopolymer composites as corrosion resistant pipe material. Geopolymer material is a general term for material synthesized from fly ash. Fly ash is an industrial by-product (coal combustion residue) with high silica content (SiO2) and Alumina content (Al2O3). In addition, there are also other elements in a relatively small percentage. This material will compound like cement if activated with Sodium Silicate. This study aims to obtain the optimum composition for high quality mechanical properties. The method used is to synthesize material with various elemental compositions. Furthermore, a mechanical test (bending test) is performed to see the effect of each element to be optimized. Besides that, a physical test in the form of SEM-EDX was also conducted to see the microstructure. Materials with optimum composition have been fabricated as pipes with centrifugal casting process. Mechanical testing of pipe samples is done by hoop tensile strength test. The test results show that the strength of geopolymer composites can achieve 58 MPa.

An assessment of effect of rotational speeds on the castings in a vertical centrifugal casting process of Tin

An assessment of effect of rotational speeds on the castings in a vertical centrifugal casting process of Tin

Solid particle erosion studies on SiC reinforced functionally graded aluminium matrix composites

The main objective of this present study is to fabricate functionally graded Aluminium alloy reinforced with silicon carbide composite by horizontal centrifugal casting process and investigate its erosion wear behaviour using Taguchi technique. Microstructural examination confirmed that the gradient structure across the radial direction and maximum particle reinforcement was found at the outer zone of the fabricated functionally graded metal matrix composite. Solid particle erosion wear experiments were carried out on the fabricated functionally graded metal matrix composite using abrasive air jet erosion test rig. Erosion process parameters such as zone distance from outer surface, Erodent velocity and Exposure time were examined using L9 orthogonal array table. The effect of erosion parameters on the erosion rate was investigated by signal-to-noise ratio and Analysis of Variance. Analysis of Variance result concluded that zone distance from the outer surface had 91.46% influence on erosion rate followed by exposure time (2.54%) and erodent Velocity (0.54%). Finally, regression equation was formed to find the optimal erosion rate and that has been validated by confirmatory experiment.

Study of Flow Behaviour in Vertical Centrifugal Casting

In centrifugal casting processes, flow of fluid layers determines the quality of the cast. However flow visualization is not possible, as mould and molten metal are opaque in nature. Therefore many research workers have resorted to understand the flow visualization process by carrying out simulation studies. Literature survey indicates that earlier investigators have studied the melt flow in horizontal centrifugal casting process by conducting cold modeling experiment using horizontal transparent mould and fluids of different viscosity. However it appears that there is no published information available in the area of influence of various parameters in the case of vertical centrifugal casting process. Therefore in this research work the cold modeling experimentation on fluids of different viscosity like water, Glycerin and SAE 90 rotated in a transparent mould at a constant room temperature had been conducted with an objective of understanding the influence of rotational speed and aspect ratio on flow patterns of different fluids subjected to vertical axis rotation. Later the flow behavior had been studied by numerical simulation through Ansys fluent software. Further for the purpose of comparison, casts of paraffin wax at different rotational speeds had been obtained and the trend of variation of the lift with the variation of rotational speed had been compared with the trend predicted using cold modeling studies and using Ansys software. From cold modeling studies it can be concluded that of the dimensional accuracy of fluid cylinder in terms of lift had been increased with increase in viscosity. The possibility of formation of complete fluid cylinder increases with increase in rotational speed and mould diameter. Howvere, at aspect ratio of 1.0 the formation of complete fluid cylinder had not been obtained.The trend of result observed in CFD study was found to be similar to the trend of results observed in cold modeling study. The study of actual paraffin cast confirmed the result obtained in cold modeling and CFD.

Mechanical characterisation of Al and Al-4%Cu alloy prepared by horizontal centrifugal casting process

Casts of aluminium (Al) and aluminium-copper alloy (Al-4%Cu) were produced using horizontal centrifugal casting method at varied process parameters such as rotational speed, aspect ratio and mould wall thicknesses. The effects of mould wall thickness and rotational speed on the microstructure of Al and Al-4%Cu alloy had been investigated. The hardness of Al casts determined was lower than that of Al-4%Cu alloy and was found to be improved than that of conventional castings. Specific wear rate of centrifugally cast Al-4%Cu alloy was lower than those of pure Al casts. The coefficient of friction and frictional force of specimens was found to be lower for the cast produced under a greater rotational speed of the mould and it was also observed that frictional force gradually increases with load. The presence of copper in aluminium base (4% Cu) has enhanced the ultimate tensile strength of the alloy.

Optimization of dry sliding wear performance of functionally graded Al6061 / 20% SiC metal matrix composite using Taguchi method

Abstract Functionally graded materials have a great demand in automotive industries to design and fabricate engineering components with high wear resistance which are suitable to the particular application. The major objective of this present work is to fabricate aluminum reinforced with SiC functionally graded metal matrix composite by a vertical centrifugal casting process and find its optimal wear factors by utilizing the Taguchi technique. An orthogonal array table and Analysis of Variance were employed to examine the effect of factors like applied load, sliding velocity and region from the external surface on the dry sliding wear of the functionally graded composite. The results showed that dry sliding wear was very much affected by the applied load followed by region from the outer surface and sliding velocity. The wear area of the specimens was then examined by using Scanning electron microscopy

Analysis of Molten Metal Distribution in the Mold of a Horizontal Centrifugal Casting

It is numerically studied the influence of the angular velocity, the molten metal viscosity, and the mold wall roughness on the molten metal distribution in the mold of a horizontal centrifugal casting process. The undesirable raining phenomenon sometimes arises in horizontal centrifugal casting. It occurs when the molten metal rains or falls from the top of the mold to the bottom while the mold is rotating. Using Computational Fluid Dynamics simulations, the conditions for the emergence of the raining phenomenon were explored in this work. For the system considered, angular velocities less than 77 rad/s cause the emergence of the raining phenomenon and accumulation of the molten metal in the lower part of the mold, whereas angular velocities greater than 77 rad/s produce a constant thickness of the molten metal and prevent raining.

Mechanical characterisation of Al and Al-4%Cu alloy prepared by horizontal centrifugal casting process

Casts of aluminium (Al) and aluminium-copper alloy (Al-4%Cu) were produced using horizontal centrifugal casting method at varied process parameters such as rotational speed, aspect ratio and mould wall thicknesses. The effects of mould wall thickness and rotational speed on the microstructure of Al and Al-4%Cu alloy had been investigated. The hardness of Al casts determined was lower than that of Al-4%Cu alloy and was found to be improved than that of conventional castings. Specific wear rate of centrifugally cast Al-4%Cu alloy was lower than those of pure Al casts. The coefficient of friction and frictional force of specimens was found to be lower for the cast produced under a greater rotational speed of the mould and it was also observed that frictional force gradually increases with load. The presence of copper in aluminium base (4% Cu) has enhanced the ultimate tensile strength of the alloy.