Aluminum gravity casting is a traditional casting process that pours molten aluminum into a sand or steel mold and solidifies it under the action of gravity. Although gravity casting can improve the strength of the final product through T6 heat treatment, it often leads to rough surfaces, obvious defects, and porosity of the parts. In contrast, aluminum squeeze casting is a more advanced process that combines the advantages of casting and forging. By applying high pressure to molten aluminum during the solidification process, squeeze casting can minimize porosity, increase material density, and achieve excellent surface smoothness. In addition, squeeze casting can improve production efficiency and make it suitable for large-scale production, with costs similar to high-pressure die casting.
Why Some Gravity Casting Applications Need to Be Replaced
Not all applications are suitable for gravity casting, especially when high performance and consistency are required.
The following are some of the main reasons why more advanced processes are needed to replace gravity casting:
Porosity and Surface Defects
Gravity casting can generate pores due to residual air and shrinkage during cooling, resulting in cavities and reduced strength.
Gravity casting is also prone to producing rough surfaces and defects, especially in sand molds.
Compared to other methods, even with steel molds, it is difficult to obtain a smooth surface.
Lower Production Efficiency
Gravity casting, particularly with sand molds, is labor-intensive and relies on manual operations, slowing production and increasing costs.
While T6 heat treatment can strengthen parts, it adds time cost, further reducing overall efficiency, and making gravity casting less suitable for high-volume production.
Limited for High-Performance Parts
Due to issues such as porosity, surface roughness, and low production efficiency, gravity casting is not ideal for applications that require high strength, durability, and precision.
With the increasing demand for product quality in various industries, many manufacturers have begun to adopt advanced processes such as squeeze casting to improve product performance and consistency.
Why Squeeze Casting Can Replace Gravity Casting
Squeeze casting provides solutions to many challenges faced by gravity casting, effectively addressing issues such as porosity and lower production efficiency.
Here are some reasons why it can be a more effective alternative:
Reduced Porosity
Squeezing casting applies high pressure during the solidification process, reducing porosity and shrinkage.
This makes the casting dense, and uniform, with fewer defects and a smoother surface, suitable for precision applications.
Strength with T6 Treatment
Squeeze casting can also undergo T6 heat treatment to obtain strength higher than gravity casting.
A denser structure ensures stable strength and a better surface finish, making it an ideal choice for automotive and aerospace components.
Better Surface Finish
The pressure of squeeze casting results in a better surface finish and smaller tolerances for the parts, thereby reducing the need for additional machining.
This allows for the production of castings with complex shapes and higher quality.
Higher Efficiency
The production speed of squeeze casting is similar to that of high-pressure die casting, making it suitable for large-scale production.
Compared to gravity casting, squeeze casting comes with a higher degree of automation, which can reduce labor costs and time spent, thereby providing stable quality for large-scale production.
The following table provides a detailed comparison of the mechanical properties of common aluminum alloys after gravity casting and squeeze casting processes:
Alloy Type
|
Process |
Tensile Strength (MPa) |
Yield Strength (MPa) |
Elongation (%) |
Hardness (HB) |
A356
|
Squeeze Casting |
300 |
175 |
6-10 |
75-90 |
A356.2 |
Squeeze Casting |
320 |
190 |
7-12 |
80-95
|
A380
|
Squeeze Casting |
330 |
180 |
2.5-4.5 |
90-100 |
A383
|
Squeeze Casting |
320 |
160 |
2-4 |
85-95 |
AlSi9Mg |
Squeeze Casting |
340 |
200 |
5-8 |
85-100
|
AlSi10Mg |
Squeeze Casting |
350 |
210 |
4.5-7 |
90-105
|
AlSi9Cu3
|
Squeeze Casting |
300 |
170 |
2.5-4 |
80-95 |
A356 |
Gravity Casting |
220 |
140 |
5-10 |
60-80
|
A380
|
Gravity Casting |
220 |
150 |
3-8 |
65-85 |
A413 |
Gravity Casting |
200 |
130 |
3-7 |
55-75
|
ADC12
|
Gravity Casting |
210 |
140 |
2-5 |
60-80 |
AlSi9Cu3 |
Gravity Casting |
230 |
160 |
3-6 |
70-90
|
AlSi10Mg
|
Gravity Casting |
250 |
170 |
4-8 |
70-100 |
AlSi7Mg
|
Gravity Casting |
210 |
140 |
5-10 |
65-85
|
CEX Casting Successful Cases
At CEX Casting, we have helped many customers transition from gravity casting to squeeze casting, demonstrating to them how we can solve the problems of porosity and high post-processing costs while achieving higher strength levels with better efficiency. Here is a typical example:
Part Name: Flange
Material: A356.2
Heat Treatment: T5
Benefits:
1. The product is internally free from pores, meeting high resistance and air-tightness requirements.
2. The entire surface is free from shrinkage holes, pits, dents, and scratches.
Conclusion
Although switching from aluminum gravity casting to aluminum squeeze casting requires new molds and process adjustments, the advantages of reducing porosity, enhancing strength, improving surface smoothness, and increasing production efficiency make squeeze casting an important choice for companies looking to level up product quality.
At CEX Casting, we specialize in guiding our customers through this transformation, providing tailored solutions to maximize the advantages of squeeze casting.
Contact us today to learn how we can help you change your manufacturing process and provide high-quality parts through squeeze casting