Aluminum Alloy Pressure Casting And Gravity Casting Technology

Due to its good plasticity, corrosion resistance and light weight, aluminum alloys are widely used in automobile manufacturing, aerospace, marine and other fields. With the development of the foundry industry, the demand for aluminum alloy and aluminum alloy castings is increasing, which will also promote the development of aluminum alloy casting industry.

At present, the casting methods of aluminum alloys are divided into two kinds: pressure casting and gravity casting. This article will analyze in detail the differences and characteristics of the two casting methods.

1.Aluminum Alloys Pressure Casting:

It refers to the process of injecting molten metal under the action of other external forces (without gravity). Pressure casting is divided into high-pressure casting and low-pressure casting. High-pressure casting is what we usually call die casting. That is, the molten aluminum is poured into the pressure chamber, and the die cavity is filled at high speed by the pressure, and the molten aluminum is solidified under pressure to form a die casting.

Aluminum Alloy Die Casting Features:

1.Surface finish is good, generally up to Ra6.3 even up to Ra1.6

2.Not heat treatable

3.High product airtightness, high casting strength and surface hardness, but low elongation

4.High mold cost and short service life

5.High productivity

6.Thin-walled parts with low machining allowance

2.Aluminum Alloys Gravity Casting:

It refers to the process in which aluminum liquid is injected into the mold under the action of the earth's gravity. Gravity casting is divided into: sand casting, metal casting (steel mold), and lost foam casting.

The most widely used is the casting of metal molds (steel molds). The molds are made of heat-resistant alloy steel. The strength, appearance and size of the cast aluminum castings are higher and better than those of other processes.

Gravity-cast aluminum liquid is generally poured into the gate manually, relies on the liquid metal's own weight to fill the cavity, exhaust, cooling, and open the mold to get the sample.

The process flow is generally aluminum melt, charge filling, exhaust, cooling, open mold, clean production, heat treatment, and machining.

Aluminum Alloy Gravity Casting Features:

1.The surface finish of the product is not good, and pits are easily generated after shot blasting

2.Aluminum castings have fewer air holes and can be heat treated

3.Low product airtightness and casting strength is not as high as pressure cating, but high elongation

4.Low mold cost and long service life

5.Low productivity, then the production cost gets increased

6.Thin-walled parts are not possible