The filling and solidification in centrifugal field, as well as the forming mechanism of off-center porosities were summarized, based on the mathematical model established for the centrifugal cast TiAl exhaust valves. The calculated results show that the centrifugal field results in the phenomenon that the flow in the valve cavity consists of forward flow and backward flow. The unsymmetrical initial temperature field causes continuous unsymmetrical variation in the following solidification, which makes the final solidified region depart from the cavity axis and then leads to the occurrence of off-center porosity. A series of optimized parameters, including the entrance velocity of 0.6 - 1.3 m/s, the rotation speed higher than 300 r/min, 80 mm or longer entrance length and 400 degrees C or higher preheated temperature of the mold, are suggested for the manufacture of permanent mold centrifugal cast TiAl exhaust valves.
部门归属
shandong univ technol, dept mech engn, zibo 255049, peoples r china. chinese acad sci, inst met res, titanium alloy lab, shenyang 110016, peoples r china.;sheng, wb (reprint author), shandong univ technol, dept mech engn, zibo 255049, peoples r china;wbsheng@sdut.edu.cn
W. B. Sheng,D. Li. Numerical simulation for permanent mold centrifugal cast TiAl exhaust valve[J]. Transactions of Nonferrous Metals Society of China,2005,15(3):631-635.
APA
W. B. Sheng,&D. Li.(2005).Numerical simulation for permanent mold centrifugal cast TiAl exhaust valve.Transactions of Nonferrous Metals Society of China,15(3),631-635.
MLA
W. B. Sheng,et al."Numerical simulation for permanent mold centrifugal cast TiAl exhaust valve".Transactions of Nonferrous Metals Society of China 15.3(2005):631-635.
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