Characteristics of Aluminum Castings and How to Pour
Cast aluminum alloy has some incomparable advantages over other castings, such as beauty, light weight, corrosion resistance, etc., which makes it widely favored by users. Especially since the lightweight of automobile, cast aluminum alloy castings have been widely used in the automobile industry.
The density of cast aluminum alloy is lower than that of cast iron and cast steel, while the specific strength is higher. Therefore, using aluminum alloy castings under the same load conditions can reduce the weight of the structure. Therefore, aluminum alloy castings are widely used in the aviation industry, power machinery and transportation machinery manufacturing.
Features of aluminum castings: light weight and corrosion resistance.
Aluminum alloy has good surface gloss and good corrosion resistance in the atmosphere and fresh water, so it is widely used in the manufacture of civil utensils.
Pure aluminum has good corrosion resistance in oxidizing acid media such as nitric acid and acetic acid, so aluminum castings also have certain applications in the chemical industry. Pure aluminum and aluminum alloys have good thermal conductivity. Heat exchange devices used in chemical production and parts required to have good thermal conductivity in power machinery, such as cylinder heads and pistons of internal combustion engines, are also suitable for manufacturing aluminum alloys.
Aluminum alloy has good casting properties. Due to the low melting point, casting methods such as metal mold and pressure casting can be widely used to improve the internal quality, dimensional accuracy, surface finish and production efficiency of castings.
Due to the large solidification latent heat of aluminum alloy, under the same weight condition, the solidification process of aluminum liquid lasts much longer than that of cast steel and cast iron, and has good flowability, which is conducive to casting thin-walled and complex castings.
During the pouring of aluminum castings, the oversized sprue is very easy to produce wrapping pores, so how to pour the aluminum castings?
1. Large aluminum castings can be poured with one or two sets of sprues, each set of which is composed of several thinner sprues.
2. When the semi-metal mold casting top-pouring process is adopted, the funnel-shaped runner can be set at the key position when it is not convenient to set up enough risers. With the continuous sinking of the runner liquid level, multiple supplementary pouring can be carried out to achieve the effect of sufficient feeding.
3 For large aluminum castings with many separators, the exhaust of the casting itself is also very important to avoid the defects of insufficient pouring.