Centrifugal Casting Method Research Articles

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill.

Investigate the Possibility of Tekcast Methods Used for Casting Polymeric Resin Materials

Abstract Contribution gives an overview of knowledge about the method of centrifugal casting with orientate on Tekcast system. Company Tekcast Industries has developed a device for centrifugal casting, extending the area of production of castings or prototyping of metal or plastic. Materials suitable for the centrifugal casting with flexible operating parameters may include non-ferrous metal alloy based on zinc or aluminum or non-metallic materials such as polyester resins, polyurethane resins, epoxy resins, waxes and the like. The casting process is particularly suitable for a wide range of commercial castings and decorative objects.

Microstructure and Mechanical Properties of a Wear-Resistant As-Cast Alloyed Bainite Ductile Iron

An as-cast bainite ductile iron with excellent mechanical properties and wear resistance was fabricated by alloying and centrifugal casting method, and the alloyed chemical composition was optimized by using the thermodynamic software Thermo-Calc. By using optical microscopy, transmission electron microscopy, scanning electron microscopy, and X-ray diffraction, the microstructure of the as-fabricated bainite ductile cast iron was characterized pertinent to the elements distribution in matrix and features of ferrite and retained austenite. The results of mechanical properties test show that the hardness and compressive strength of this alloyed ductile iron are 52 HRC and 2,200 MPa, respectively. The as-cast bainite ductile iron possesses highly abrasive wear resistance and the reason can be ascribed to the solid solution of the elements Si, Ni, Cu, and Mn in the austenite and the formation of carbides of elements Cr and Mo. The strength of bainite ductile iron is increased by the acicular bainitic ferrite in the matrix.

Fabrication of Self-Lubricating Cu-Based Composite Containing Graphite Particle by Centrifugal Mixed-Powder Casting

Reduction of frictional coefficient at sliding position can improve wear resistance of material. In previous studies, Cu-based composites containing graphite particles have been reported. Since graphite is better lubrication material, the Cu-based composites containing graphite particles have better wear property comparing with the pure Cu. However, these composites are mainly fabricated by sintering method and its strength is relatively low. In this study, Cu-based composites containing graphite particles are fabricated by centrifugal mixed-powder casting. The centrifugal mixed-powder casting is novel centrifugal casting method combined with powder metallurgy. Using this casting method, the Cu-based composites containing graphite particles are successfully obtained. The graphite particles are distributed in the Cu matrix and no casting defects are observed. Moreover, wear resistance of these Cu-based composites are much better than pure Cu, and the frictional coefficient between these composites and bearing steel as the counter part is reduced by dispersion of the graphite particles. Furthermore, it is found that the optimum area fraction of the graphite particles to improve the wear resistance of the present Cu-based composite is from 15% to 21%.

Three Body Abrasion Wear Behaviour of Functionally Graded Aluminium/B4C Metal Matrix Composite Using Design of Experiments

Functionally graded aluminium metal matrix composite (Al-Si5Cu3/B4C) was fabricated through liquid metallurgy route followed by horizontal centrifugal casting method. The casting was obtained under the centrifugal die rotating speed of 1250rpm and has the dimensions of length 150mm, outer diameter 160mm and thickness 20mm. The microstructural test was performed at the surfaces those were at the distances of 3, 9 and 15mm from the outer periphery of the casting. The tribological performance of the composite was studied using Design of Experiments. The wear experiments were conducted on the dry abrasion tester as per L27 orthogonal array using silica sand AFS 50/70 as an abrasive medium. The parameters such as load (28, 40, 52N), speed (100, 150, 200rpm) and distance (3, 9, 15mm from the outer periphery of the casting) were varied for three levels. The response studied was wear rate and the wear performance was analysed by choosing “Smaller-the-better” characteristics. The influence of parameters such as applied load, sliding speed and distance from the outer periphery of the casting on the response was studied by using Analysis of Variance and Signal-to-Noise ratio. The results revealed that distance from the outer periphery of the casting has the major impact on the wear rate followed by load and speed. The worn out surfaces were subjected to Scanning Electron Microscope analysis and the wear mechanisms were observed.

Microstructure and mechanical properties of Mg–5Sn alloy fabricated by a centrifugal casting method

Mg–5Sn alloy are successfully fabricated by a horizontal centrifugal casting method. Developed columnar dendritic crystals under the gravity casting condition can be mostly transformed into fine equiaxed grains by the centrifugal casting. Compared with the gravity casting, compression strength, yield strength and elongation-to-failure are significantly improved by the centrifugal casting, which increase from 181.6 to 257.5MPa, 38.7 to 52.3MPa and 14.9% to 21.2% on position r1 (centrifugal radius r1=0.05m), respectively. Moreover, the centrifugal casting also enhances work-hardening ability of the alloy. The transformation of crystals results in the enhancement of the compression properties and work-hardening ability. The results obtained here will shed some light on special casting methods of Mg alloys, which is potential to develop new light alloys with high strength and elongation.

Structure and mechanical properties of Al-based gradient composites reinforced with primary Si and Mg2Si particles through centrifugal casting

The structure and mechanical properties of a new type of Al-based discontinuous gradient composites prepared by using the ternary Al-19Si-5Mg alloys as the raw material adopting the centrifugal casting method were investigated. Structurally, the composites are divided into two zones: a reinforced zone with the high volume fraction of primary Si and Mg2Si particles and an unreinforced zone with no or a few particles. In the reinforced zone, the primary particles are evenly distributed, with the sizes of the primary Si particles 80–120 μm, and that of primary Mg2Si particles 20–50 μm. The properties test results show the reinforced zone has higher Rockwell hardness and better wear resistance than the unreinforced zone, due to the complementary reinforcement relationship between the primary Si and Mg2Si particles and their high volume fraction.

Experimental optimization in turning of in-situ AlB2 reinforced AlMg3 matrix composites produced by centrifugal casting method

Ceramic particle-reinforced aluminum matrix composites are gaining attention especially from the automotive and aerospace industry requiring light-weight and high-strength materials for various applications. Since the AlB2 reinforced composites are relatively new materials, there is no investigation into the machinability of such materials in the literature. Therefore, the aim of this paper is to study machinability of AlB2/Al-Mg3 composite materials to optimize cutting force and surface roughness during turning operation. Taguchi’s statistical approach has also been utilized for the optimization of the process parameters. The optimum conditions providing the lowest cutting force and surface roughness were estimated. For the experimental planning, L8 (27) orthogonal array and the smaller-the-better response criterion were selected to obtain optimum conditions. Analysis of variance was used to determine the most significant parameters affecting the cutting force and surface roughness generated. The optimum condition was predicted from the combination of following factors and their respective levels; the second level of material type (AlB2/Al-Mg3), first level of cutting tool (TiN coating), first level of feed rate (0.08 mm/rev) and first level of cutting speed (350 m/min). Confirmation tests were performed to determine the effectiveness of Taguchi’s optimization method using the optimal levels of test parameters. A good agreement with a confidence level of 99.5% has been observed between the predicted and tests results for both cutting force and surface roughness.

Fabrication of Al/Diamond Particles Functionally Graded Materials by Centrifugal Sintered-Casting Method

The continuous graded structure of functionally graded materials (FGMs) can be created under a centrifugal force. Centrifugal sintered-casting (CSC) method, proposed by the authors, is one of the fabrication methods of FGM under centrifugal force. This method is a combination of the centrifugal sintering method and centrifugal casting method. In this study, Al/diamond particle FGM was fabricated by the proposed method.

横型遠心鋳造と縦型遠心鋳造の液相挙動の違い

A centrifugal casting method is a key technology for producing high quality rolls which are used in a rolling process in steel industry. Because the surface quality of steel products highly depends on the roll quality and it is affected by liquid motion in the centrifugal casting method, control of the liquid motion is essential for supply of defect free rolls to the steel industry. In this research, liquid flow in the centrifugal casting method has been numerically calculated for clarification of difference of liquid motion in a horizontal type centrifugal casting method and a vertical one. The mainly obtained results are as follows. The center of the gravity periodically oscillates and its cycle is longer than the rotation cycle of the mold in the both cases of the horizontal and vertical types. Its time average in the horizontal type locates above the center axis of the mold while that in the vertical type is the same with the center axis. Increase in apparent viscosity in the vicinity of the mold wall accelerates the damping of the oscillating motion of the center of the gravity.

Functionally Graded Bronze/Tungsten-Carbide Castings: A Characterization and Property Study

Abstract The contact resistance and wear behavior of electrical contact surfaces is a function of hardness, applied load, and material constituents. This work presents a characterization of the mechanical and physical properties of conducting alloys fabricated as functionally graded metal matrix composites (MMCs), in particular, tungsten-carbide-filled bronze. Tungsten-carbide reinforcing particles are attractive in this application for their high hardness and concomitant wear resistance. When used as bushings, bearings, and sleeve materials, bronze has improved wear performance with the addition of tungsten-carbide particles, which improves the hardness of the contact surface. Bronze might also be attractive as a potential electrical conductor when a need exists for high-strength, wear-resistant contact surfaces as found in circuit breakers and sliding electrical contacts. An overview of two types of MMC production methods, sedimentation and centrifugal casting, is presented. MMCs fabricated using the two different methods are compared and contrasted based on physical and mechanical properties. The use of centrifugal casting provides a more effective improvement in physical and mechanical properties plus significant improvement in hardness with relatively low reduction in base-material conductivity was observed. The centrifugal casting method allows for a more tailored product in terms of locating enhanced material properties within the casting.

Stress Field Simulation of Compound Cast Rollers during Centrifugal Casting Process

The stress field of compound cast rollers during centrifugal casting process was investigated in this work. A finite element (FE) model was built to simulate the internal stress fields during cooling process, in which phase transformation was considered. The mechanical parameters employed in stress numerical simulation were measured by using thermal/mechanical simulator. The residual internal stress of the compound cast roller by centrifugal casting method was measured by using X-ray stress analyzer. The simulated results are in agreement with the measured ones very well. According to this model, the temperature and stress fields of the compound cast roller during centrifugal casting process were simulated.

Preparation of Gradient ZTA Ceramic by Centrifugal Slip Casting Method

Gradient Zirconia toughened alumina (ZTA) ceramics with high fracture strength and toughness were prepared using centrifugal slip casting method. Aqueous Al2O3-20vol% ZrO2 slurries with different solid contents were prepared and the rheological characteristic of the slurries were investigated. The effect of solid loading of slurries on green density difference of ZTA ceramic compacts was observed. Mass segregation of Al2O3 and ZrO2 particles were studied. Microstructure and bending property of the sintered ZTA ceramics were investigated. The results show that the segregation phenomenon of Al2O3-ZrO2 slurries comes form the difference of settling velocity of Al2O3 and ZrO2 particles. With the increase of solid content of slurries, the gradient distribution of green density becomes unconspicuous. After sintered at 1550○C for 2 h, the gradient ZTA ceramics centrifuged with 20vol% slurries have high sintered density (99.2% TD) and continuous gradient distribution of Al2O3 and ZrO2 particles. The fracture strength and toughness of gradient ZTA ceramic are 732MPa and 5.4MPam1/2, respectively.

Investigation of corrosion behaviors in chloride solutions of G-X 10CrNiMoNb 18-10 austenitic stainless steel produced by different casting techniques

In this study, corrosion resistance of G-X 10CrNiMoNb 18–10 austenitic stainless steel parts, which had been produced through sand molded casting and centrifugal casting methods, and exposed to two-step heat treatments and cooled in different mediums (water, oil, air and oven), in 3.5% NaCl solution were examined according to weight loss, potentiodynamic polarization and impedance spectroscopy. According to the obtained results, it was found that corrosion rate of G-X 10CrNiMoNb 18–10 austenitic stainless steel, which had been cast through the sand molded casting method, heated up to the 1st stage (1065–1120°C), and then cooled in the air, the lowest.

High speed sliding wear behavior of recycled WCP-reinforced ferrous matrix composites fabricated by centrifugal cast

A discarded/scrap WCP/Fe–C composites roller rings was re-melted in a 50kg medium frequency induction furnace, and a recycled composites was manufactured by centrifugal casting method using the composites re-melts. Dry sliding wear properties of the recycled composites have been investigated using a pin-on-disc wear tester at room temperature under loads of 50, 100 and 150N and sliding speeds of 60 and 80m/s. Results show that the microstructure of the recycled composites consists of un-dissolved WCP and bainite matrix. Wear rate of the recycled composites increases with the increase of load and sliding speed. And the friction coefficient of the recycled composites decreases with the increase of load and sliding speeds. The wear rate of the recycled composites almost is same as the primary composites, and the friction coefficient is obviously higher than that of the primary composites under same test conditions. Finally, the mechanisms of the dry sliding wear for the recycled composites are discussed.

Effect of the Rotating Speed of Centrifugal Machine on Microstructures and Properties of Recycled WC<sub>P</sub>/Fe-C Composites

The dead or scrap WCP/Fe-C composites parts were remelted via medium frequency induction furnace. Two recycled composites rings were made of the remelted mixture by centrifugal casting method at 720rpm and 920rpm, respectively. The effect of rotating speed of centrifugal machine on microstructures and properties of the recycled composites rings were investigated by mechanical property tester, SEM, EDS, and XRD. The results show that the recycled rings are a composite structure consisting of outer recycled composites region reinforced with undissoved WCP and core Fe-C alloy region unreinforced. The undissoved WCP-distribution in the recycled composites region is even. At the rotating speed of 720 rpm, the particle volume fraction in the recycled composites region reaches 54 vol.%, the hardness and impact toughness attain to HRC55.8 and 3.5J/cm2, respectively. As the rotating speed is raised to 920 rpm, the particle volume fraction rises to about 70 vol.%, the hardness increases to HRC63.3 and yet the impact reduces to 2.8 J/cm2. The microstructure in the inner Fe-C alloy region consists of bainitic, precipitated carbides with short rod like shape and graphite phase. Finally, the high-speed sliding wear behaviour of the recycled composites rings was investigated in the paper. Keywords: The dead or scrap composites parts; Recycled composites; rotating speed of centrifugal machine; Microstructures and properties.

Three-Dimensional Molding Based on Microstereolithography Using Beta-Tricalcium Phosphate Slurry for the Production of Bioceramic Scaffolds

We report on a three-dimensional (3D) molding technique of fabricating bioceramic scaffolds. In this method, ceramic slurry is cast into a 3D polymer master mold, which is fabricated via microstereolithography, by a centrifugal casting method. The polymer master mold is thermally decomposed, so that a complex 3D bioceramic scaffold can be produced. In experiments, the decomposition process of the polymer model was optimized by the master decomposition curve theory to reduce harmful cracks in a green body. As a result, we could produce not only precise lattice models but also a sophisticated porous scaffold using beta-tricalcium phosphate (β-TCP) slurry. This bioceramic 3D molding technique based on microstereolithography will be useful for tailor-made tissue engineering and regeneration medicine.

Solidification behavior, glass forming ability and thermal characteristics of soft magnetic Fe–Co–B–Si–Nb–Cu bulk amorphous alloys

The effect of varying Cu content on the bulk glass forming ability (GFA) of (Fe 0.36Co 0.36B 0.192Si 0.048Nb 0.04) 100−XCu X alloys ( X = 0, 0.5, 0.75 and 1.0) is revealed by investigating the thermal behaviors and phase competitions upon solidification. The changes in GFA are interpreted in terms of suppression of consecutive solidification reactions via microstructural and thermal features. Instead of the type of the primary crystallization product originating from the prevalent atomic order in the glass or supercooled liquid, precipitation of faceted binary and higher-order pro-eutectic compounds such as (Fe,Co) 2B and (Fe,Co)NbB from the alloy melt and resulting skewed eutectic coupled zone are correlated with the observed GFA. With the employed centrifugal casting method, the (Fe 0.36Co 0.36B 0.192Si 0.048Nb 0.04) 99.25Cu 0.75 alloy shows the largest critical thickness of 3 mm and the best soft magnetic properties such as 1.58 T saturation magnetization intensity and 11.7 A/m coercivity after annealing.

Swage casting of A380 alloy

Swage casting is a new casting technique which combines the advantages of squeeze, centrifugal and semi-solid casting methods. In this new casting method, components with one rotating axis can be produced on a swage casting machine from molten metal in a one-step operation. A shape like a “bomb-body” is chosen to demonstrate the advantages of this new method by using A380 Al–Si–Cu alloy. The same alloy is also cast with centrifugal and squeeze casting methods. In this study, the swage casting method and its features are briefly described. The final microstructures, mechanical properties and amount of porosity of the cast pieces produced by squeeze, centrifugal and swage casting methods are compared. Swage cast pieces showed a different composition of microstructure that consists of fine dendritic particles at the chill ends and a mixture of spherical and rosette shaped particles at the core. The swage cast pieces also have a slightly higher mechanical strength as indicated by tensile strength and Brinell hardness values.

The Microstructure and Properties of Restored WC<sub>P</sub>/Fe-C Composites

A restored WCP/Fe-C composites is manufactured by centrifugal casting method. The microstructure and properties of the restored composites have been investigated by SEM, X-ray diffraction and properties tester. The results show that the distribution of WCP in the restored composites is even, Size of WCP is obviously reduced, and their volume fraction attained to about 70 vol.%. The mechanical properties and wear behavior of the restored composites are almost the same as those of the primary composites.