Preliminary Study On Foam Ceramic Centrifugal Filtration For Zinc Alloy

Zinc alloy is often used to manufacture drop hammer die which forming complexsheet metal parts. This paper aims to seek new type of pollution-free alloy purificationtechnology to remove inclusions of zinc alloy for some air enterprise.To meet the requirements of enterprise of continuous, big flow and highcleanliness, this paper proposed a new type of centrifugal filtration purification methodson the basis of conventional foam ceramic filtration purification technology.The melt flow characteristics and the effect of process of foam ceramic filtration inthe centrifugal force from the fluid mechanics were first analyzed, as well as therelationship between the purification probability of foam ceramic filtration and thestructure of filter.Three kinds of centrifugal filter devices were designed and manufactured in thisstudy. During the test Ⅰ the temperature of the centrifugal rotor, the core componentof the centrifugal filter device, was not enough, which lead to the formation of craters inthe filtered zinc alloy. And zinc alloy melt could not get through ceramic filtercontinuously and were solidified in the flow channels. On the base of test Ⅰ, thecentrifugal filter device was redesigned in test Ⅱ, and especially, a holding furnace wasdesigned and manufactured to preheat the centrifugal rotor which solve the shrinkageproblem, the relationship between the speed of the centrifugal rotor and the filtrationflow was tested in test Ⅱ. A centrifugal filter device for production was designed in testⅢ. The total thickness of filter was60mm, and the minimum aperture of filter was40ppi, the filtration flow reached to200kg/min, fully meet the requirements of theenterprise on the filtration flow.Mechanical performance testing and microstructure analysis for purified andunpurified Zinc alloy specimens were made. Results show that via purification zincalloy mechanical properties were obviously improved, the tensile strength increased by12.26%, the elongation increased by30.37%; the fracture mode changed from cleavagefracture to quasi-cleavage fracture; the volume of inclusions significantly reduced andthe inclusion size is mostly less than10μ m.