Papers by Keyword: Roll-Casting

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Authors: Ying Zhou, Ming Hui Huang, Da Heng Mao, Tao Liang
Abstract: Three-dimensional FEM simulations of fluid-thermal analysis of the fluid fields including the front-box and the 3C-style nozzle of aluminum roll-casting was performed by using FLOTRAN module of ANSYS. The advanced result analysis based on post-processing of ANSYS was conducted by MATLAB. According to the allowable inhomogeneity and its application of velocity and temperature at outlet, the most possible broken regions of aluminum sheets at outlet could be predicted in the case of speed increasing of the drawing-sheet and thickness reducing of the aluminium sheet during roll casting.
Authors: Ryoji Nakamura, T. Asai, Hisaki Watari, Shinji Kumai
Abstract: Rheo-casting of 4045 aluminum alloy bar was operated using an unequal diameter twin roll caster and a cooling slope. The semisolid slurry was made by the cooling slope. The thickness of the bar was 12 mm and width was 100mm. The casting speed was 1m/min. Quantity of the melt poured on the cooling slope was important to make sound bar. The primary crystal became spherical, and its size was about 40μm.
Authors: Da Heng Mao, Guan Zhong Zhao, Jian Ping Li, Jian Bing Hu, Sheng Fang Zhang
Abstract: With composite energy-field of ultrasonic field and electromagnetic field introduced into the roll-casting process,AZ31B magnesium alloy has been acquired successfully,during this process,the effect of composite field on structure and properties of AZ31B magnesium roll-casting alloy are studied. The result shows that the composite field can decrease the grain size greatly from 60-80μm to 12-18μm compared with the conventional roll-casting(without out-field), improving the tensile strength and yield strength by 13% and 35% respectively and the elongation increased by 82.2%(average value).Meanwhile,the microstructure of magnesium alloy obtained with the composite field are more uniform after annealing,mechanical properties are improved greatly as well.
Authors: Jin Tao Li, Guang Ming Xu, Jian Zhong Cui
Abstract: The effect of electromagnetic field on microstructure of roll-casting 5052 aluminum alloy sheet has been investigated and analyzed. The results indicate that imposing static magnetic field can refine the grains of 5052 aluminum alloy during the roll-casting; accordingly, imposing static magnetic field and alternating current at the same time, the grains are remarkably refined and equiaxed due to electromagnetic oscillation effect.
Authors: Jin Tao Li, Guang Ming Xu, Jian Zhong Cui
Abstract: The roll-casting technology of 5000 series aluminum alloy is one of the difficulties at present. Roll-casting technology was employed in this paper and high quality 5005 aluminum alloy sheets were fabricated successfully under different conditions. The solidification of melt in roll-casting process is the rapid directional solidification. The effect of magnetostatic field on microstructure of 5005 aluminum alloy sheet by roll-casting has been investigated and analyzed. The results indicate that imposing magnetostatic field can refine the grains of 5005 aluminum alloy.
Authors: P.A. Karnezis, G. Durrant, Brian Cantor
Authors: Antonio de Pádua Lima Filho, Márcio Iuji Yamasaki
Abstract: The aim of this work is to study the solidification conditions necessary to produce good quality/low defect metal alloy strip when thixorolling directly from the semi-solid state. To facilitate the study lead/tin alloys were chosen for their relatively low operating temperature. The objective is to extrapolate these findings to the higher temperature aluminium alloys. Three alloys (70%Pb- 30%Sn, 60%Pb-40%Sn, 50%Pb-50%wtSn) were used particularly to study the influence of the solidification interval. The equipment consists of a two roll mill arranged as an upper and lower roller, where both rollers are driven at a controlled speed. The lower roller is fed with semi solid alloy through a ceramic nozzle attached to the lower end of a cooling slope. Several types of nozzle and their position at the roller were tested. This produced different solidifications and consequently different finished strip. The alloys were first cast and then poured onto the cooling slope through a tundish in order to create a continuous laminar flow of slurry and uniformity of metal strip quality. The pouring was tested at different positions along the slope. The cooling slope was coated with colloidal graphite to promote a smooth slurry flow and avoid the problem of adherence and premature solidification. The metallic slurry not only cools along the slope but is also initially super-cooled to a mush by the lower roller whilst at room temperatures, thus enabling thixorolling. It was also found that the nozzle position could be adjusted to enable the upper roller to also contribute to the solidification of the metallic slurry. However the rollers and the cooling slope naturally heat up. Temperature distribution in these zones was analysed by means of three thermocouples positioned along the cooling slope and a fourth in the base of the semi solid pool within the nozzle. The objective being to design an optimum pouring and cooling system. The formed strip was cooled down to room temperature with a shower of water. Microstructures of the thixorolling process were analysed. The differences in solidification conditions resulted in differing qualities of finished strip and corresponding defect types, all of which are a serious quality issue for the rolled product.
Authors: Ryoji Nakamura, Hisaki Watari, Shinji Kumai
Abstract: Two kinds of roll casters, which were suitable for high speed roll casting, were devised. One was a vertical type twin roll caster, and the other was an unequal diameter twin roll caster. The semisolid roll casting using a cooling slope was adopted to these roll casters. The solid fraction was smaller than 5%. 3 mm thickness of 6111 strip was cast at 60 m/min by the vertical type twin roll caster, and 5 mm thickness of 6111 strip was cast at 30 m/min by the unequal diameter twin roll caster. The microstructure of the as-cast strip was equiaxed and spherical, not columnar. The mechanical properties of the strip rolled from roll-cast strip were almost as same as that of the strip made from cast ingot.
Authors: Ryoji Nakamura, Shinsuke Suzuki
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