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1.
The twin-roll strip casting of magnesium 总被引:18,自引:0,他引:18
Commonwealth Scientific & Industrial Research Organization has been working since 2000 to develop twin-roll strip casting
of magnesium alloy. The primary objective was to significantly reduce the manufacturing cost of the magnesium sheet through
the twin-roll casting process. This article describes the goals and challenges of this project as well as pilot plant test
results.
For more information, contact D. Liang, CSIRO Manufacturing & Infrastructure Technology, Normanby Road, Clayton, Victoria
3168, Australia; +61-3-9545-2981; fax +61-3-9544-1128; e-mail daniel.liang@csiro.au. 相似文献
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The twin-roll casting of magnesium alloys 总被引:2,自引:0,他引:2
S. S. Park W. -J. Park C. H. Kim B. S. You Nack J. Kim 《JOM Journal of the Minerals, Metals and Materials Society》2009,61(8):14-18
Recently, technologies for twin-roll casting have been widely developed to efficiently fabricate the lightweight Mg alloy
sheets that are quite attractive for numerous weight-sensitive applications. This paper reviews the recent progress in the
twin-roll casting of Mg alloys, focusing on the processing aspects that have close relations to the solidification behavior
of Mg alloy strips. In addition, recent attempts to develop new Mg alloys utilizing the metallurgical advantages attainable
by this novel casting process are also presented. 相似文献
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采用双辊铸轧技术制备AZ31镁合金板坯,利用X射线衍射、金相显微镜、扫描电子显微镜以及能谱分析等技术对该板坯的物相进行分析.结果表明: 双辊铸轧AZ31镁合金板坯中的物相主要有а-Mg枝晶、枝品间富溶质а-Mg和不规则的块状Mg17(Al,Zn)12相组成的离异共晶以及弥散分布于晶内的星形细小Al8Mn5相;在双辊铸轧过程中,随着Mg液温度的降低,过饱和的Mn以Al8Mn5相的形式从Mg液中析出,而后细小的Al8Mn5相随着а-Mg初晶的长火进入枝晶胞内部;а-Mg初晶长大的同时,Al、zn等元素在枝晶问未凝固的液相中富集,最终在枝晶问形成依附于初晶的富溶质а-Mg和不规则的块状Mg17(Al,Zn)12相组成的离异共晶. 相似文献
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N. M. Zapuskalov 《International Journal of Cast Metals Research》2013,26(1):45-49
Ferrous alloy strips of width 150 mm and thickness 150–300 μm were obtained by rapidly cooling from the molten state at ~ 105 Ks?1 with the pressing force of the rolls during casting 1.5 kN mm?1 and a rotational speed of 8 ms?1. Typical composition of the strip was Fe—4.5%Si, Fe—23%Cr—5%Al or Fe—12%Al. The roller wear mechanism and strip quality were investigated using two sets of cylindrical, water-cooled, bronze roll moulds. It was found that the width of the strip obtained by rapid quenching in rolls is determined by the consumption of metal and depends on fluctuations in the molten bath. Strip thickness increases with bath depth. The lenticular form of the strip is obtained by bending of the rolls, and the biconcave form, using a thick water-cooled roll sleeve, is a result of the thermal expansion of the roll.Roller wear and changes to the strip microrelief were investigated using different alloys. The roughness of the surfaces of both strip and roller increased throughout the casting process. The amount of increase depended more on the alloy than on the melt temperature. The average values of the angles of the slopes of micro-peaks were measured and compared and decreased along the strip. Comparison of the coefficient of anisotropy across the width of the strip showed a decrease from the edge to the middle of the strip. The apparent reason for the appearance, on local areas of the strip surface, of oxide pellicles is revealed. 相似文献
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Thermal deformation of a large marine propeller casting during solidification and cooling was analyzed by a coupled thermomechanical
finite-element analysis (FEA). The calculated displacements on the blade in the z-direction were compared with the measured
values that confirmed the effectiveness of FEA for the prediction of thermal deformation. The effect of the shake-out time
and method on the deformation of the propeller casting was also investigated. The longer the shake-out time, the smaller the
deformation. For controlling the deformation of the propeller casting, the sequential shake-out was a more efficient method
than the simultaneous shake-out. 相似文献
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Coupled analysis of temperature and flow during twin-roll casting of magnesium alloy strip 总被引:2,自引:0,他引:2
The distribution of temperature and flow fields in cast-rolling zone was obtained through the direct coupled solution of finite element method. Two vortexes appeared in the cast-rolling zone during twin-roll casting. The flow velocity along thickness of the magnesium alloy strip was heterogeneous, which resulted in the microstructure with the flow trace inclined to the cast-rolling direction. The temperature difference between the strip surface and at the center was about 150 °C at the inlet and it declined to about 25 °C at the exit. The increase of the casting temperature caused the raise of the strip temperature at the exit. The calculated temperature was consistent with the measured temperature. 相似文献
8.
《Journal of Materials Processing Technology》2014,214(6):1275-1284
The interfacial heat transfer between the casting and the substrate from liquid/solid contact to solid/solid contact with pressure was investigated using a set of equipment designed according to the characteristics of the top side-pouring twin-roll casting process. The interfacial heat transfer behavior of this process consists of 4 stages: chilling, solidification shrinkage, compression and cooling. High values of the IHTC ranging from 50,000 to 90,000 W/m2 °C were detected in the chilling stage, followed by a sharp decrease in solidification shrinkage stage (4000–8000 W/m2 °C). Due to the pressure, which modeled the effect of rolling in twin-roll casting, the IHTC bounced back to 6000–20000 W/m2 °C, according to different conditions. The influence of process variables such as pressure magnitude, compress speed, pouring temperature, surface roughness and alloy composition had been discussed. Because of the compress action, the influence of these variables performed in a different way, but it was concluded that the way to improve the contact conditions always accompanied with an increase in the IHTC. 相似文献
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在研究双辊连铸纯铝薄带凝固过程的基础上,基于金属凝固的基本原理,并运用现代计算机仿真技术建立双辊连续铸轧纯铝薄带凝固的异质形核,枝晶尖端的生长动力学(KGT),柱状晶向等轴晶生长的转变(CET)的解析模型;建立基于元胞自动机(CA)的双辊连铸纯铝薄带凝固组织的仿真模型,为双辊连铸薄带凝固组织的仿真模拟奠定基础,从而为双辊薄带连铸工艺提供一定的理论指导。同时,利用双辊薄带连续铸轧纯铝凝固微观组织过程验证数学模拟的可行性。 相似文献
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Nucleation and growth model based on Cellular Automation(CA) incorporated with macro heat transfer calculation was presented to simulate the microstructure of aluminum twin-roll casting. The dynamics model of dendrite tip (KGT model) was amended in view of characteristics of aluminum twin-roll casting. Through the numerical simulation on solidification structure under different casting speeds, it can be seen that when the casting speed is 1.3 m/min, that is, under conditions of conventional roll casting, coarse columnar grains dominate the solidification structure, and equiaxed grains exist in the center of aluminum strip. When the casting speed continuously increases to 8 m/min, that is, under the conditions of thin-gauge high-speed casting, columnar grains in solidification structure all convert into equiaxed grains. Experimental and numerical results agree well. 相似文献
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K. O. Yu Ph.D. J. J. Nichols B.S. M. Robinson M.S. 《JOM Journal of the Minerals, Metals and Materials Society》1992,44(6):21-25
Finite-element thermal modeling offers the capability of simulating casting solidification conditions. By combining thermal modeling and inspection, a defect map can be established to enable prediction of casting microstructures and defects. Gamma-prime size, dendrite-arm spacing, equiaxed grain size, shrink, hot tearing, misrun, and other features can all be predicted. 相似文献
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铝带坯双辊铸轧过程瞬态传热数学模型 总被引:2,自引:1,他引:1
采用拉格朗日随体坐标建立了铝双辊铸轧过程瞬态传热数学模型。在数学模型中考虑了金属凝固动力学条件和采用试验测定的辊/铝带坯界面接触换热系数边界条件,用有限差分方法对控制方程进行了数值求解,并由现场测试数据验证了传热数学模型的正确性。 相似文献
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以二辊φ160 mm×150 mm铸轧机为研究对象,以1060纯铝为材料,利用ProCAST的CA-FE模块,建立了铸轧过程的热-流-组织间接耦合模型,研究了铸轧工艺参数对凝固组织与热变形的影响.基于微小变形率下凝固组织形貌未发生变化的假设,建立了铸轧区凝固组织精细化标准.通过铸轧实验验证了仿真模型的准确性,确定了Ki... 相似文献
17.
Jian Zeng Roger Koitzsch Herbert Pfeifer Bernd Friedrich 《Journal of Materials Processing Technology》2009,209(5):2321-2328
The magnesium twin-roll strip casting process is investigated with a test caster at the IME. The flow field in the melt cannot be investigated optically, therefore numerical simulations have been undertaken to show the flow field in the Mg melt, the solidification between the two rolls and the cooling of the strip. The three-dimensional, turbulent flow field for different steady state casting points, in the process gap, have been calculated, including the solidification of the magnesium alloy melt. Within the process gap of the casting process the flow field shows similar flow structures. A big vortex in the casting channel and a much smaller vortex between the two rolls occur. With the increase of the casting speed the mushy zone is moved towards the kissing point. This can be interpreted due to a smaller force on the rolls. Nevertheless, the solidification on the rolls is so strong, that rolling between the two rolls happens. 相似文献
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《Intermetallics》2006,14(8-9):987-993
Twin-roll strip casting was utilized to fabricate the sheet products of Zr- and Cu-base bulk amorphous alloys with quite different glass forming abilities (GFAs). Simulation of the solidification behavior of the these amorphous forming alloys during twin-roll strip casting shows that suitable cooling rate can be achieved by twin-roll strip casting to form amorphous structure through the thickness of sheet. Optimum twin-roll strip casting conditions have been suggested based on the simulation results. Actual twin-roll strip casting shows that both Zr-base alloy with high GFA and Cu-base alloy with much less GFA can be strip cast forming amorphous structure. The results indicate that the twin-roll strip casting is a viable process for continuous fabrication of sheets of bulk amorphous alloys with a wide range of critical cooling rates. 相似文献