Preparation method of dope for metal type casting of magnesium alloy thin-walled component

Abstract

The invention discloses a preparation method of a dope for metal type casting of a magnesium alloy thin-walled component. The dope comprises the following components in percentage by weight: 1.5 to 2.5 percent of kieselguhr, 2 to 3 percent of magnesium oxide powder, 1.2 to 1.8 percent of titanium dioxide powder, 1 to 2 percent of zirconite powder, 1.5 to 2.5 percent of bentonite, 2 to 4 percent of asbestos powder, 1.2 to 1.4 percent of silica sol and the balance of alcohol. The preparation method comprises the following steps of 1) weighing the materials according to the proportion; 2) taking 30 percent of the total alcohol, adding the bentonite into the alcohol, stirring until the bentonite is suspended, sequentially adding the magnesium oxide powder, the titanium dioxide powder and the zirconite powder into the suspension, and stirring the suspension for about 15 to 25 minutes to uniformly mix the materials and obtain a mixture I; 3) mixing and stirring the kieselguhr, the asbestos powder and the silica sol for about 10 to 20 minutes, adding 20 percent of the total alcohol into the mixture, and stirring the materials for about 5 to 15 minutes to uniformly mix the materials and obtain a mixture II; and 4) mixing the mixture I, the mixture II and 50 percent of residual alcohol, and stirring the materials for about 20 to 30 minutes to obtain the dope.

Description

technical field [0001] The invention relates to the field of casting, in particular to a method for preparing a coating for metal mold casting of magnesium alloy thin-walled parts. Background technique [0002] Metal mold casting, also known as hard mold casting, is a casting method in which liquid metal is poured into metal molds to obtain castings. Cast molds are made of metal and can be used repeatedly (hundreds to thousands of times). The castings that metal mold casting can produce at present have certain restrictions in terms of weight and shape. For example, the weight of castings should not be too large; the wall thickness is also limited, and it is difficult to cast smaller castings with wall thickness. [0003] Due to the fast cooling rate of magnesium alloy thin-walled parts in the metal mold casting process, it is easy to form defects such as cold shut, pinholes and shrinkage porosity in the castings, so that the castings are scrapped. Therefore, how to improve ...

AI Technical Summary

Problems solved by technology

[0005] It can be seen that the coatings used for metal molds of thin-walled parts in the prior art are all aimed at cast aluminum alloys, but there are few reports on magnesium alloys. Due to the difference in properties between magnesium alloys and aluminum alloys, it is impossible to use the coatings in the prior art. Metal mold casting coatings for thin-walled aluminum alloys are directly applied to magnesium alloys. Therefore, it is urgent to develop a metal mold casting coating suitable for magnesium alloy thin-walled parts