Ceramic Foam Filter Tiwai Aluminium effectively removes large inclusions in the aluminum liquid, and absorbs fine inclusion particles of micron size, which plays the role of improving surface quality, improving product performance, improving microstructure, and improving yield.

Aluminum alloy casting process performance
Generally understood as a combination of those properties that are more prominent in the process of filling the mold, crystallization and cooling. Fluidity, shrinkage, air tightness, casting stress, getter.
These characteristics of aluminum alloy depend on the composition of the alloy, but are also related to the casting factors, the heating temperature of the alloy, the complexity of the mold, the gate riser system, the gate shape, etc.

1. Liquidity
Flowability refers to the ability of the alloy liquid to fill the mold. The size of the fluidity determines whether the alloy can cast complex castings. Eutectic alloys have better fluidity in aluminum alloys. A
There are many factors that affect the fluidity, mainly the composition, temperature and solid phase particles of metal oxides, metal compounds and other pollutants in the alloy liquid, but the external fundamental factors are pouring temperature and pouring pressure (commonly known as pouring head) The height. A
In actual production, in addition to strengthening the smelting process (refining and slag removal), it is also necessary to improve the moldability (sand mold permeability, metal mold exhaust and temperature) without affecting the alloy. Under the premise of casting quality, increase the pouring temperature to ensure the fluidity of the alloy. A
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2. Shrinkage
Shrinkage is one of the main characteristics of cast aluminum alloys.
Generally speaking, the alloy is divided into three stages from liquid casting to solidification and cooling to room temperature, which are liquid shrinkage, solidification shrinkage and solid shrinkage.
The shrinkage of the alloy has a decisive influence on the quality of the casting, which affects the size of the shrinkage cavity of the casting, the generation of stress, the formation of cracks and the change in size.
Usually casting shrinkage is divided into body shrinkage and linear shrinkage. In actual production, linear shrinkage is generally used to measure the shrinkage of the alloy.
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Aluminum alloy shrinkage, usually expressed as a percentage, is called shrinkage.
1. Body contraction Body contraction includes liquid contraction and solidification contraction. A
From casting to solidification, the casting alloy liquid will have macro or micro shrinkage in the later solidification area. This macro shrinkage hole caused by shrinkage is visible to the naked eye and is divided into concentrated shrinkage hole and dispersed shrinkage hole.
The diameter of the concentrated shrinkage hole is large and concentrated, and is distributed on the top of the casting or the hot section with a thick section. The dispersive shrinkage pores are scattered and fine, most of them are distributed in the casting axis and hot joints.
Micro shrinkage pores are difficult to see to the naked eye, and most of the micro shrinkage pores are distributed under the grain boundaries or between the dendrites of the dendrites. A
Shrinkage and looseness are one of the main defects of castings. The reason for this is that liquid shrinkage is greater than solid shrinkage.
It was found in production that the smaller the solidification range of the cast aluminum alloy, the easier it is to form concentrated shrinkage cavities, and the wider the solidification range, the easier it is to form dispersive shrinkage cavities. Therefore, in the design, the cast aluminum alloy must conform to the principle of sequential solidification, that is, the casting is in The shrinkage of the body during the liquid state to solidification should be supplemented by the alloy liquid. Shrinkage and looseness are concentrated in the outer riser of the casting.
For aluminum alloy castings that are prone to dispersion and loosening, the number of risers is more than that of concentrated shrinkage holes, and cold iron is set at the location where looseness is prone to increase the local cooling speed to make it solidify simultaneously or rapidly.
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2. The size of line shrinkage will directly affect the quality of castings. The greater the linear shrinkage, the greater the tendency of aluminum castings to crack and stress. The larger the size and shape changes of the casting after cooling. A
Different casting aluminum alloys have different casting shrinkage rates. Even if the same alloy has different castings, the shrinkage rates are different. On the same casting, the shrinkage rates of its length, width and height are also different. Should be based on specific circumstances.

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