A Comprehensive Guide to A356 Aluminum

A356 aluminum is a high-quality, cast aluminum alloy well-known for its excellent mechanical properties, corrosion resistance, and versatility. It is widely used in fields such as automotive, aerospace, and industrial machinery that require strength, lightweight, and precision casting.

Now let’s have a deeper understanding of the A356 aluminum.

From chemical composition and mechanical properties to comparisons with other aluminum alloys like 6061 aluminum, and the perfect combination of A356 aluminum with CEX Casting’s squeeze casting process, this guide will explore everything you need to know about A356 aluminum.

A356 Aluminum Composition

A356 aluminum is a cast aluminum alloy primarily composed of aluminum, silicon, and magnesium, with small amounts of other elements.

Its composition is carefully designed to enhance the alloy’s mechanical properties, castability, and overall performance.

The main elements in A356 aluminum are as follows:

Aluminum (Al): 91.1% – 93.3%
Silicon (Si): 6.5% – 7.5%
Magnesium (Mg): 0.2% – 0.45%
Copper (Cu): ≤0.2%
Zinc (Zn): ≤0.1%
Iron (Fe): ≤0.2%
Manganese (Mn): ≤0.1%
Titanium (Ti): ≤0.2%
Other Elements: Trace

A356 Aluminum Mechanical Properties

A356 aluminum comes with a good combination of mechanical properties, making it a suitable material for a range of applications.

Below are the main mechanical properties of A356 aluminum (these properties may vary depending on the specific heat treatment applied to the alloy):

Mechanical Properties Values
Tensile Strength 207 – 310 Mpa
Yield Strength 138 – 228 Mpa
Elongation 3 – 10%
Hardness 70 – 80 HB

A356 Aluminum Characteristics

The characteristics of A356 aluminum set it apart as the preferred choice for many applications.

Some of its notable characteristics include:

Excellent Castability

Due to its relatively high silicon content, A356 aluminum comes with good fluidity, making it capable of producing castings with complex shapes and fine details.

The low shrinkage rate during the solidification process helps reduce internal defects like porosity, making it an ideal material for high-precision components.

Good Corrosion Resistance

The low levels of copper and other potentially corrosive alloying elements in A356 help minimize galvanic coupling corrosion, which can occur when aluminum is in contact with dissimilar metals.

The presence of silicon also enhances the overall stability of the alloy, contributing to its corrosion resistance in harsh environments such as marine and automotive applications.

High Strength-to-Weight Ratio

Aluminum is naturally lightweight, with a density of around 2.68 g/cm³, much lower than that of steel or other metals.

In A356 aluminum, the addition of magnesium increases tensile and yield strength, particularly when the alloy is heat-treated to the T6 temper.

This combination of low weight and enhanced strength makes A356 aluminum ideal for applications such as automotive and aerospace.

Good Weldability

The high silicon content in A356 aluminum can reduce the possibility of hot cracking during welding.

Silicon can lower the melting point of the alloy and improve its fluidity, which makes the welding process smoother and more stable.

A356 Aluminum Applications

A356 aluminum is widely used in various industries due to its impressive characteristics.

Some of the most common applications include:

Automotive Components

Widely used in the automotive industry for engine blocks, cylinder heads, wheels, suspension components, etc, A356 aluminum is highly valued for its lightness and strength.

The alloy’s good castability allows the production of castings with complex geometries, which are in demand in automotive design.

Aerospace Parts

Various aircraft parts such as structural components, shells, and brackets.

Its high strength-to-weight ratio helps improve fuel efficiency and performance.

In addition, A356 aluminum’s ability to maintain strength at low temperatures and its corrosion resistance makes it suitable for components in satellite systems and other space applications.

Industrial Machinery

A356 aluminum is widely used in industrial machinery components such as housings, brackets, and heat exchangers.

Its high strength-to-weight ratio ensures that the parts are both durable and lightweight, which is crucial for reducing energy consumption and improving the efficiency of machinery.

In addition, A356 aluminum has excellent corrosion resistance and the ability to withstand high operating stresses, making it an ideal choice for machinery used in harsh and corrosive industrial environments.

Marine Hardware

The corrosion resistance of A356 aluminum makes it an ideal choice for marine hardware and other components exposed to saltwater environments.

Examples include propellers, pumps, and fittings, where long-term durability is crucial.

Electrical Enclosures

A356 aluminum is used to produce electrical enclosures due to its heat dissipation and corrosion resistance capabilities.

The excellent castability allows for the creation of enclosures with complex internal geometries, making it suitable for modern electronic products.

A356 Aluminum vs 6061 Aluminum

A356 aluminum is a casting alloy mainly used for complex casting shapes, with excellent casting performance, making it an ideal choice for applications such as automotive parts and machinery.

It achieves a good balance between strength, ductility, and corrosion resistance, especially after T6 heat treatment.

In contrast, 6061 aluminum is a forged alloy widely used in extruded parts and structural components due to its high strength-to-weight ratio, good machinability, and excellent weldability.

6061 aluminum is typically more suitable for machining applications that require higher strength and precision.

Table 1: Elemental Composition Comparison

Element A356 Aluminum (%) 6061 Aluminum (%)
Aluminum (Al) 91.1 – 93.3 95.8 – 98.6
Silicon (Si) 6.5 – 7.5 0.4 – 0.8
Magnesium (Mg) 0.2 – 0.45 0.8 – 1.2
Copper (Cu) ≤0.2 0.15 – 0.40
Zinc (Zn) ≤0.1 ≤0.25
Iron (Fe) ≤0.2 ≤0.7
Manganese (Mn) ≤0.1 ≤0.15
Titanium (Ti) ≤0.2 ≤0.15
Other Elements Trace Trace

Table 2: Mechanical Properties Comparison

Property A356 Aluminum 6061 Aluminum
Tensile Strength (MPa) 207 – 310 260 – 310
Yield Strength (MPa) 138 – 228 240 – 270
Elongation (%) 3 – 10 8 – 12
Hardness (HB) 70 – 80 95 – 105

Table 3: Physical and Chemical Properties Comparison

Property A356 Aluminum 6061 Aluminum
Density (g/cm³) 2.68 2.70
Melting Point (°C) 570 – 580 580 – 650
Electrical Conductivity (% IACS) 33 – 36 40 – 44
Coefficient of Thermal Expansion (10^-6 /°C) 21.4 23.4
Thermal Conductivity (W/m·K) 151 167
Corrosion Resistance Good Good

Table 4: Applications Comparison

Application Fields A356 Aluminum 6061 Aluminum
Automotive Industry engine blocks, cylinder heads, structural parts suspension arms, wheels, truck frames
Electronics enclosures, housings, heat sinks, battery cases laptop cases, smartphone frames, heat sinks
Industrial Machinery pump housings, valve bodies, gearbox housings, brackets, heat exchangers robotic arms, machine frames, support brackets
Aerospace landing gear components, turbine housings, helicopter rotor hubs fuselage panels, wing spars, connectors
Construction window and door frames, lighting fixtures, decorative elements structural beams, railings, curtain walls

Can A356 Aluminum Be Heat-Treated?

Yes, A356 aluminum can undergo heat treatment.

The most commonly used heat treatment method for A356 aluminum is the T6 process, which includes solution heat treatment, quenching, and aging treatment.

In the T6 heat treatment process, A356 aluminum is first heated to a high temperature to dissolve the alloying elements into the aluminum matrix.

After reaching the desired temperature, the alloy will rapidly quench, usually in water, to lock in the alloying elements.

The quenching process produces a supersaturated solid solution, which is then subjected to aging treatment at lower temperatures to precipitate alloying elements, thereby improving the strength and hardness of the material.

The result of T6 heat treatment is a significant improvement in the tensile strength, yield strength, and hardness of A356 aluminum, making it an ideal material for industries such as automotive, aerospace, and industrial machinery.

In addition, the heat treatment process also improves the fatigue and wear resistance of the alloy, further enhancing its durability and performance in critical applications.

What Is A356-T6 Equivalent to?

A356.2-T6

A variant of A356 alloy, but with slightly different mechanical properties.

The tensile strength and yield strength of A356.2-T6 may be slightly higher, depending on the exact composition and processing conditions.

6061-T6

Although not identical, 6061-T6 has similar mechanical properties, despite being a forged alloy rather than a cast alloy.

In certain applications, A356-T6 can serve as a substitute for 6061-T6, especially when parts allow for casting production.

AlSi7Mg0.3-T6 (European Standard)

This alloy is equivalent to A356 in Europe, with similar composition and mechanical properties.

When heat-treated to the T6 condition, it offers comparable strength, hardness, and durability, making it a suitable alternative for regions where A356 is not standard.

Why A356 Aluminum Is Suitable for Squeeze Casting?

A356 aluminum is suitable for squeeze casting mainly because the process itself aims to improve the quality and performance of cast components, while the inherent properties of A356 aluminum are very consistent with squeeze casting.

The reasons are as follows:

The high silicon content endows A356 aluminum with excellent fluidity, which enables it to accurately fill complex molds under high pressure of squeeze casting, reducing the risk of defects and ensuring the high quality of the final product.

After T6 heat treatment, A356 aluminum can achieve excellent mechanical properties.

This process enhances its strength, hardness, and durability, making it suitable for demanding applications that require long-lasting performance.

In addition, the mechanical properties of A356-T6 aluminum are comparable to those of hot-forged 5-series or 6-series aluminum alloys.

This similarity makes it an ideal alternative to the forging process, especially when production cannot be achieved through forging, such as parts with complex geometric shapes.

squeeze casting equipment

A356 Aluminum Squeeze Casting by CEX Casting

At CEX Casting, we focus on combining A356 aluminum with our advanced squeeze casting process.

Squeeze casting combines the advantages of traditional casting and forging processes, resulting in parts with excellent mechanical properties, superior surface finish, and high dimensional accuracy.

Below are our case studies showing the parts we have successfully developed with A356 aluminum squeeze casting and the mechanical properties achieved by the parts.

Case Studies

Hydraulic Brake Part

This is a hydraulic brake part for electric motorcycles, which requires the internal injection of brake oil during use.

Therefore, this part needs to be free of internal porosity and leakage.

Previously, high-pressure die casting was used for production, resulting in internal porosity and often causing oil leakage problems during use.

Our squeeze casting process, combined with A356-T6 aluminum, perfectly solves this problem.

The high pressure applied during solidification by squeeze casting, combined with the good flowability and castability of A356 aluminum, enables the part to achieve no internal porosity, thereby meeting the requirements of air tightness.

A356 Hydraulic Brake Parts

Folding Part

This folding part is used in fitness equipment, which requires high strength to cope with harsh usage scenarios.

A356 aluminum with our squeeze casting process frees the part of internal porosity, which improves the strength, and the use of T6 heat treatment enhances the part’s strength even further.

The mechanical properties of the part can now be achieved:
Yield Strength: 250Mpa
Tensile Strength: 300Mpa
Hardness: 92Hb

A356 Folding Parts

Mechanical Properties

The following figure shows the mechanical property test report of our A356 aluminum squeeze castings.

These enhanced properties achieved through the squeeze casting process make our A356 aluminum castings withstand higher stresses and come with a longer service life than conventional die castings, which is suitable for the most demanding applications.

A356硬度测试

A356拉伸测试

Conclusion

A356 aluminum is a multifunctional and high-performance alloy, that achieves an excellent balance between strength, weight, and corrosion resistance, whether dealing with complex shapes, high stress, or challenging corrosive environments.

At CEX Casting, we are committed to providing top-quality A356 aluminum castings, utilizing our advanced squeeze casting process to meet the highest industry standards.

Whether you work in the automotive, aerospace, or any other industry that requires precision and reliability, A356 aluminum is a material that can help you achieve your goals.

Contact us today to learn how we can support your next project with our expertise in A356 aluminum squeeze casting.

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