Papers by Keyword: Centrifugal Casting

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Authors: Safar Rostamzadeh, Behzad Niroumand, Ali Maleki
Abstract: In the present research, the possibility of single stage semi-solid casting of a hypereutectic gray cast iron in a sand mold was investigated. For this purpose, a specially designed chilled sprue sand mold rigged to a vertical centrifugal casting machine was used. The molten cast iron was poured in the chilled sprue sand mold at 1275 oC at a rotation speed of 400 rpm. Two control samples were also poured at 1275 oC under gravity and centrifugal casting conditions in the same mold without sprue chilling. Microstructures and mechanical properties of the specimens were then characterized. The results showed that the average length and thickness of the primary solid phase, i.e. the Kish graphite, and those of the eutectic flake graphite were smaller in semi-solid centrifuged castings and their hardness were higher than those of the control samples. The results are discussed in terms of the shearing and chilling effects of the designed sprue during the initial stages of pouring.
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Authors: Yi Kun Luan, Nan Nan Song, Yun Long Bai, Xiu Hong Kang, Dian Zhong Li
Abstract: A novel segregative carbide was discovered during the manufacture of high speed steel roll. The carbide with rectangular shape is a type of MC carbide not yet reported in the open literature. It is a face centered cubic carbide with a lattice parameter a=0.414445 nm, very close to the VC carbide but with a different chemical composition. The M represents the metallic elements (at.%): 91.80 V, 3.17 Cr, 2.19 Fe and 2.83 Mo.
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Authors: Alexandre Velhinho, P.D. Sequeira, Francisco Manuel Braz Fernandes, José D. Botas, L.A. Rocha
257
Authors: Zhen Kai Zhao, Yan Pei Song, Zhi Ming Feng
Abstract: The mathematical physical model of the unmelted WC particle distribution in the centrifugal force field was established in cylindrical coordinate system using continuity theory and hydromechanics. According to the migration rule of WC particle in the Fe-C alloy melt under centrifugal field, the mathematical equation of particle volume fraction distribution including centrifugal casting parameters was formulated. The mathematical equations were calculated by solving the mathematical equation with numerical analysis, and also the distribution regularity of WC particle in composite layer under different temperature and different Centrifugal speed was achieved. The results show that the particle reinforced composite with a gradient distribution along thickness was prepared by centrifugal casting. The gradient distribution of the particle changes with pouring temperature and centrifugal speed. And the theoretical data accord with experiment data compared to the experimental measurement.
1610
Authors: P. Midhun Krishnan, Sanil Hari, E. Jayakumar, T.P.D. Rajan, K. Narayan Prabhu
Abstract: Aluminium based FGM rings, reinforced by in-situ primary Si and primary Si/ Mg2Si hybrid reinforcement were successfully fabricated by centrifugal casting and micro structural, chemical, hardness and corrosion characteristics were evaluated. It was observed that in Al-20Si ring the primary Si particles were present mostly in inner region and few in outer region where as in Al-20Si-3Mg ring both the primary silicon and Mg2Si were completely found in the inner region only resulting in a graded FGM structure. The hardness values were measured along radial direction of samples and variations corresponding to micro structural variation were analysed. Optical Emission spectroscopic studies have revealed the remarkable compositional changes along radial direction. Corrosion characteristics were also evaluated both in particle rich and depleted regions.
11
Authors: Sang Mok Lee, S. Yang, S.T. Kim, Y.S. Park, B.M. Moon
Abstract: Microstructural features, mechanical properties, and corrosion properties of a SAF2205 duplex stainless steel (DSS) were systematically investigated as functions of cooling rate during casting and heat treatment conditions. The choice of a duplex stainless steel was a SAF2205 alloy, of which composition is 0.03C, 21~23Cr, 4.5~6.5Ni, 2.5~3.5Mo, 0.08~0.2N, 1.0Si, and 2.0Mn with remaining Fe. A 5-stepped sand mold and the permanent Y-block mold were used to check the effect of cooling rate during solidification. The microstructural characteristics, such as grain size, the d/γ ratio, the existence of the carbides and σ phase has been noticed to greatly change with the variation of cooling rate during the casting procedure. Various heat treatment conditions were also examined to achieve the optimized mechanical properties of DSS. Based on the preliminary examination, the feasibility study of utilization of centrifugal casting has been carried out for the production of better quality DSS pipe components. Melting and casting practices of DSS during centrifugal casting in an air atmosphere were systematically investigated in order to obtain the optimized process parameters.
2527
Authors: Emad Oveisi, Farshad Akhlaghi
Abstract: In the present study, Al-Si samples with a graded structure were produced via horizontal centrifugal casting. The distribution of primary and eutectic silicon particles within the produced specimens was investigated by optical microscopy. The microstructure of one end of the sample (closed to rotating axis) consisted of primary Si particles distributed within a eutectic matrix. The volume fraction of these particles decreased towards the other end of the sample and exhibited mostly primary Al-α and eutectic structure. Microhardness and macrohardness measurements conducted along the sample length showed a gradual decreasing value from one end (near the rotation axis) towards the other end of sample demonstrating functionally graded properties. These results were rationalized in terms of the lower density of Si compared to Al alloy which provided the movement of Si particles under the action of centrifugal forces during rotation.
865
Authors: N. Harish, S. Hamritha, S. Kiran Aithal
Abstract: Present work is focused on Horizontal centrifugal casting process, by which a wear resistant material with considerable strength can be designed. A material of heterogeneous microstructure designed in which a high volume fraction of hard particles is dispersed at the inner surface, where better wear properties are needed, and a gradually decreasing lower volume fraction of hard particles at the outer surface. By this, a better strength and ductility will be achieved at the desired surfaces. The present work is focused on the preparation of cylinder liners using centrifugal casting for Al-17wt%Si. These cylinder liners are characterized for Microstructure, Hardness, Tensile strength and Wear.
399
Authors: B.A. Kulakov, V.K. Dubrovin, A.V. Karpinskiy
Abstract: The simulation process of centrifugal casting using titanium aluminide intermetallic alloys has been described in the context of the low-pressure duct turbine blade designed for the gas-turbine engine. Initially, the preliminary theoretical calculations have been performed together with experimental casting when developing the casting production technologies. The obtained results allowed setting a range of the boundary conditions for computing simulation of pouring and solidification. ProCast the computing simulation system for the casting processes has been used. Various alternatives of the casting layout in the mold as well as the gating system configurations have been examined by means of this system. In the course of simulation process such faults have been detected as formation of shrinkages into the shroud platform and (or) blade footing; or significant decrease in technological yield when the risers’ dimensions expand or the casts’ number decreases in the mold. Considering the results of the performed computer experiments, the most efficient gating system has been ultimately defined to obtain the casts using titanium aluminide intermetallic alloys by centrifugal casting.
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