Papers by Keyword: Extrusion Process

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Authors: Jin Biao Zhang, Jing Wen Wang, Zong Yin Duan
Abstract: More and more attention is being paid to extrusion with multi-hole die in the manufacturing industry because of its advantages of high efficiency, high accuracy. However, there is a key factor that need to be taken into cosideration, such as diehole lacation on the multi-hole die. A optimization strategy integrated regression analysis for the multi-hole die design in profile extrusion process based on finite element simulation, GA, and regression theory was proposed, and an optimized model is established to predict the best location of diehole. A few examples show that the strategy is effective, feasible, and the model is accurate, applicable.
1548
Authors: Łukasz Madej, Peter D. Hodgson, Maciej Pietrzyk
Abstract: An investigation of the application of a multi scale CAFE model to prediction of the strain localization phenomena in industrial processes, such as extrusion, is presented in this work. Extrusion involves the formation of a strong strain localization zone, which influences the final product microstructure and may lead to a coarse grain layer close to the surface. Modelling of the shape of this zone and prediction of the strain magnitude will allow computer aided design of the extrusion process and optimisation of the technological parameters with respect to the microstructure and properties of the products. Thus, the particular objective of this work is comparison of the FE and CAFE predictions of strain localization in the shear zone area in extrusion. Advantages and disadvantages of the developed CAFE model are also discussed on the basis of the simulation results.
25
Authors: Xiao Feng Wang, Xiao Ming Zhou, Jie Yang, Jin Wen Zou, Wu Xiang Wang
Abstract: According to the defects of powder metallurgy superalloy, especially the influence and damage of inclusions on properties of disk, the deviation between nondestructive testing and metallographic testing of inclusions in FGH96 alloy isothermal forging disk was investigated. Meanwhile, the types and deformation mechanism of inclusions were studied. The results showed that the buried depth tested by metallographic detection was less 67-180μm than nondestructive testing. The size of inclusions with metallographic detection was less about 18-50μm than nondestructive testing. The major types of inclusions in practical disk were Al2O3 and Al2O3-SiO2, the inclusions run through several grains, no matter Al2O3 or Al2O3-SiO2. The Al2O3 inclusion and matrix was purely mechanical bonding, but the Al2O3-SiO2 had reaction zone. There was remarkable effect of extrusion process on crushing and dispersing Al2O3 inclusion, but which was unremarkable for Al2O3-SiO2.
526
Authors: Jian Gang Lv, Gao Feng Quan, Rui Chun Li, Chun Yuan Shi, Ying Bo Zhang, Xi'an Xie
Abstract: According to the profile section of transport equipment, the wide and hollow AZ31 magnesium alloy profiles was self-designed. Extrusion molding performance of the profiles, the law of microstructure and mechanical properties were studied when billets pretreatment and extrusion temperature were changed. The conclusions are as follows: (1) The grains of AZ31 profiles extruded by pre-extrusion billet are smaller and the strength is better, its maximum tensile strength is 280MPa. (2) Other processes being equal, the grains of AZ31 profiles are smaller and strength is higher, but the plastic is bad, when the extrusion temperature is 300°C. However, both strength and ductility of AZ31 profiles are better, when the extrusion temperature is 350°C. (3) Wide and Hollow AZ31 profiles perform significant heterogeneity and anisotropic characteristics on mechanical properties.
21
Authors: Ronaldo Soares Teixeira, G.H.D. Tonoli, S.F. Santos, Juliano Fiorelli, Holmer Savastano, F.A. Rocco Lahr
Abstract: The extrusion process can produce composites with high-density matrix and fibre packing, low permeability and fibre matrix bond strengthening. This process is also compatible with the use of vegetable fibres as raw materials in the production of cost-effective construction elements such as ceiling panels. Sugar cane bagasse fibres (SCF), one of the largest cellulosic agroindustrial by-products of sugar and alcohol industry available in Brazil, are a renewable resource usually used as a biomass fuel for the boilers. The remaining bagasse is still a source of contamination to the environment, so there is a great interest on exploiting novel applications to sugar cane bagasse fibres. In this work, the effect of SCF on extruded cementitious composite performance was evaluated. Three different contents of SCF were considered, using cellulose pulp as secondary micro-reinforcement to improve the resistance to the appearance of microcracks. Composites were prepared using a laboratory Auger extruder with vacuum chamber and were tested after 28 days of water curing and after 200 accelerated ageing cycles. Modulus of rupture (MOR) and Tenacity (TE) of extruded composites were assessed by four point bending test. Water absorption and apparent volume were determined by water immersion. Microstructure behavior was evaluated by mercury intrusion porosimetry and scanning electron microscopy (SEM). Results indicated that the introduction of larger fibres increased tenacity (TE) at 28 days and favored a higher amount of macropores (0.1 to 1 mm); SEM observations confirmed that fibre degradation occurred after 200 cycles.
450
Authors: Asit Kumar Gain, Ho Yeon Song, Byong Taek Lee
Abstract: The continuously porous t-ZrO2 bodies were fabricated by the extrusion process. The average pore size of the 2nd passed samples was about 260μm in diameter. The maximum bending strength value was about 177MPa. For the evaluation of their biocompatibility, human osteoblast like MG-63 cells and osteoclast like Raw 264.7 cells were cultured on the top surface of the porous t-ZrO2 bodies. The osteoblast cells were grown with spindle shape, condensed circular growth and three-dimensional network type. In contrast, the osteoclast cells appeared with pebble stone structure.
277
Authors: Sung Jin Kim, Sung Jin Park, Hee Gon Bang, Sang Yeup Park
Abstract: In the study, we attempted to synthesize the cordierite by the reaction of fly-ash and alumina, silicon dioxide, magnesia powders. And also porous cordierite honeycomb filte r for air purification was fabricated from the combination of synthetic cordierite using fly as h and pore forming agent. As the extrusion processing parameters of honeycomb, binder formul ation and extrusion conditions were investigated. Graphite addition was effective for the reduce ment of extrusion pressures. Porous cordierite honeycomb was fabricated with high porosity ( 58%), and good compressive strength (69MPa) with 30wt% graphite at low sintering tempera ture(1150oC).
621
Authors: Kai Wu, Shui Juan Shi, Yi Long Wang, Bin Bin Peng
Abstract: Pellet mill has been widely used in feed industry and biomass energy industry and ring die is its critical component. The structure of the ring die hole not only determines whether the feed can go through the hole smoothly, but also has a great effect on the abrasion of die hole. The finite element simulations that describe the feed extruding in different die-hole have been done and the axial nodal displacements as well as equivalent force along the die-hole internal surface are extracted. Then the feed extruding in different conicities of inlets are also analyzed. It is shown that the camber inlet is better than the conical inlet when taking the abrasion of die-hole into account. Furthermore, the smaller entrance angle of conical inlet is better.
350
Authors: Hidetoshi Somekawa, Toshiji Mukai
Abstract: The fracture toughness was investigated using in an extruded AZ31 magnesium alloy with an initial grain size of 1.0 μm. Since the small scale yielding condition was not satisfied with the present thin thickness, the value of plane-strain fracture toughness, KIC = 27.9 MPam1/2, was measured from Stretched Zone analysis. The values of KIC in AZ31 magnesium alloys were dependent on the grain size. The grain refinement was found to be one of the improvement methods for fracture toughness in magnesium alloy.
155
Authors: Ji Ming Zhou, Le Hua Qi, Hai Bo Ouyang, He Jun Li
Abstract: Magnesium matrix composites are attractive for weight critical application, such as automotive and aerospace components, because of its high specific strength and stiffness. Extrusion process directly following vacuum infiltration (EVI) can eliminate the porosity and obtain the well-aligned and uniform fiber distribution during the fabrication of Csf/AZ91D composite. This process combines the advantages of gas pressure infiltration, squeeze casting, and semi-solid extrusion. The mechanical properties of the magnesium are improved greatly by introducing the carbon fibers into the magnesium matrix through the EVI process. In the present study, the carbon short fiber reinforced magnesium matrix composites Csf/AZ91D were fabricated by EVI process. The microstructure and tensile property of Csf/AZ91D composites were investigated. The results showed that the microstructure of the composite presented a uniform distribution of carbon short fibers in the matrix and good interfacial integrity. The yield strength and stiffness of the composites increased with increasing carbon short fiber content, but at the cost of ductility. Nonetheless, Csf/AZ91D can keep relatively high ductility during the improvement of strength compared with reported composites in the literatures. Increasing carbon fiber content in the composite was not always beneficial to the ultimate tensile strength at the same magnitude. When the fiber content exceeds 10%, the matrix was not strengthened as greatly as under 10% fiber content. The yield strength improvement was attributed to (i) load-bearing effects due to the presence of carbon short fiber reinforcements; (ii) grain size refinement due to the large extrusion deformation; (iii) generation of dislocations to accommodate CTE mismatch between the matrix and the particles.
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