A356 aluminum is a popular casting alloy that offers excellent strength, ductility, and corrosion resistance. It is commonly used in high-stress applications, such as automotive and aerospace components, due to its outstanding mechanical properties and ability to withstand extreme temperatures. The A356 alloy can be cast using various techniques, including sand casting, die casting, and investment casting, to produce complex and precise parts with tight tolerances.

Performance and classification of die-cast aluminum alloy

 For a long time, due to the air hole defects in the die casting itself, so they are often limited to some decorative parts, by the load of small parts manufacturing, so the development of die casting aluminum alloy has been stuck in several models. However, with the development of production and the mastery of die casting technology, people put forward more requirements in expanding the application scope of die casting, such as in the structural improvement of bicycles to reduce the weight, one of the most important measures is to use aluminum alloy instead of steel to make bicycle parts.

 Die-cast aluminum alloy should meet the performance requirements of the parts, in order to smooth pressure casting, it should also have the following properties:

1. in the heat is not high, even in the solid and liquid line temperature range, it should have better plastic rheological ability, namely under the pressure, seemingly thick aluminum alloy liquid still has excellent fluidity, easy to fill complex cavity, ensure good quality of die casting surface, reduce the shrinkage holes in the casting. At the same time, improve the working condition of die-casting, improve its working life;
2. The line shrinkage rate is small, and has a certain high temperature strength, to avoid the crack and deformation of the casting, improve the dimensional accuracy of the casting;
3. The crystallization temperature range is small, which can reduce the possibility of shrinkage holes in the casting;
4. With a certain high temperature solid state strength, to prevent the deformation or rupture of the casting when the mold is opened;
5. at room temperature should have a certain strength, in order to improve the mechanical strength and surface hardness of the die casting as far as possible;
6. There is no chemical reaction with die casting type, the affinity is small, prevent bonding and casting, casting mutual alloying;
7. It is not easy to inhale and oxidation under high temperature melting, so as to meet the requirements of long-term insulation during die casting.

Die-cast aluminum alloy has good use performance and process performance, so the die-casting of aluminum alloy has developed rapidly, widely used in various industrial sectors, the dosage is far higher than other non-ferrous alloys, in the production of die-casting occupies an extremely important position. According to the basic elements contained, the cast aluminum alloy can be divided into Al-Si alloy, Al-Cu alloy, Al-Mg alloy and Al-Zn alloy.

1. Al-Si alloy Because co-crystal Al-Si alloy has the characteristics of small crystallization temperature interval, large solidification latent heat, large specific heat capacity, and small linear shrinkage coefficient, its casting performance is generally better than other aluminum alloys, its filling performance is good, and thermal cracking and shrinkage tendency is relatively small. Al-Si co-crystal contains the lowest amount of brittle phase (silicon phase) in the tissue, and the mass fraction is only about lO%, so its plasticity is better than other aluminum alloys. The only remaining brittle phase in the tissue can also reduce its brittleness by deterioration treatment. The experiments show that the Al-Si co-crystals still maintain good plasticity at the temperature near their freezing point, which is not found in other aluminum alloys. A considerable number of co-crystals in casting alloy tissue to ensure its good casting performance; the increase of co-crystals will make the alloy brittle and reduce the mechanical properties, there is some contradiction between the two. However, because Al-Si co-crystal has good plasticity and the requirements of mechanical properties and casting properties, so Al-Si alloy is the most widely used die-casting aluminum alloy. In China's die-casting aluminum alloy varieties, the vast majority of Al-Si alloy, this kind of alloy has low strength, cutting performance is not good enough, thread processing difficulties and other phenomena, so in recent years, China is developing high strength alloy.
2. Al-Zn alloy High mechanical properties of Al-Zn alloy die casting can be obtained after natural aging. The intensity is significantly increased when its zinc mass fraction is greater than 10%. The disadvantage of this alloy is poor corrosion resistance, the tendency of stress corrosion, easy to hot crack when die casting. The commonly used Y40l alloy has a good liquidity, easy to fill the cavity, the disadvantage is that the pore formation tendency is large, silicon, iron content is less, easy to heat crack.
3. Al-Mg alloy The characteristics of Al-Mg alloy are: good mechanical properties at room temperature; strong corrosion resistance; poor casting performance; large mechanical properties fluctuation and wall thickness effect; decreased plasticity and even cracking of die casting. The disadvantages of Al-Mg alloy partially offset its advantages, making is affected in its application.
4. Die-cast aluminum alloy with special properties Die-cast aluminum alloy with special properties developed at home and abroad are: Decorative Al-Mn alloy: suitable for anodic oxidation treatment and coloring treatment, high elongation, and considerable corrosion resistance. But its strength is not high, the shrinkage rate is large, easy to stick the mold. Heat treatment Al 1 Si-Cu alloy: can be incomplete manual aging after quenching and complete manual aging after quenching to the maximum hardness. In addition, there are surface treatment and heat treatment compound Al 1 Mn-zn alloy, wear-resistant type over-common crystal Al-Si alloy and explosion-proof anti-vibration type Al-zn alloy. In addition, there are die-cast aluminum alloy composite materials, which have not been widely produced and applied.