Aluminum alloy has been widely used in automobile manufacturing, aerospace, shipbuilding and other fields due to its good plasticity, corrosivity and light weight. With the development of China's manufacturing industry, the demand for aluminum alloy and aluminum alloy castings is constantly increasing, which will also promote the development of aluminum alloy foundry industry. At present, the casting method of aluminum alloy is divided into two kinds: pressure casting and gravity casting. In this paper, the differences and characteristics between two kinds of casting technology are analyzed in detail.
Aluminum alloy casting process can be divided into two kinds: gravity casting and pressure casting.
Aluminum alloy pressure casting refers to the molten metal in other external force (not including gravity) into the casting process, the pressure casting is divided into high pressure casting and low pressure casting.
High-pressure casting is usually we say die-casting, the liquid aluminum into the pressure chamber, through its high pressure to fill the mold cavity, and the liquid aluminum to solidify under pressure to form aluminum castings.
Aluminum die-casting features are:
1, the product surface finish, generally up to Ra6.3 or up to Ra1.6.
2, not heat treatment.
3, product airtight, casting strength and surface hardness, but low elongation.
4, higher mold costs, short life.
5, high production efficiency.
6, can produce thin-walled parts, machining allowance small.
Gravity casting of aluminum alloy is the process of injecting molten aluminum into the mold under gravity of the earth. Gravity casting is divided into sand casting, metal casting (die casting) and lost casting.
Now the most used is the mold (steel mold) casting, the mold made of heat-resistant alloy steel, cast aluminum castings strength, size, appearance, etc. are higher than the casting of other castings.
Gravity cast aluminum liquid is generally poured into the gate by hand, relying on the weight of liquid metal filled cavity, exhaust, cooling, mold to get the sample, the process is generally: aluminum melt, pouring filling, exhaust , Cooling, mold, cleaning, heat treatment, processing.
Aluminum alloy gravity casting features:
1, the product surface finish is not high, easy to produce pits after shot blasting.
2, aluminum castings less pores, can be heat treatment.
3, the product of low density, less strength, but high elongation.
4, lower mold costs, long mold life.
5, low production efficiency, thereby increasing the cost of production.
6, the process is relatively simple, not suitable for the production of thin-walled parts.
In the production process of choice of the product, mainly based on the thickness of the workpiece to choose from, the product wall thickness greater than 8mm, the die-casting will cause a lot of pores in the wall, so thick wall thickness of the product can choose the gravity casting process is completed .