Best Aluminum Alloys for Investment Casting

Investment casting is a manufacturing process that utilizes the principles of lost-wax casting to produce intricate parts and components that are not achievable with any other metal forming process. In addition, the 3D printing of casting patterns allows for the fast production of prototypes and complex production parts. Many engineers and manufacturers find that aluminum is one of the best metals to use for investment casting because it’s lighter, stronger, and more affordable than many steel alloys.

Continue reading to learn about the benefits of aluminum investment casting, as well as the best aluminum alloys to use.

Benefits of Using Aluminum Alloys

Aluminum investment castings typically weigh less than similar castings made with other metals. However, there are various additional benefits to using aluminum alloys including:

• Cost Savings: Aluminum investment castings are typically less expensive to produce, and also require less energy.
• Corrosion Resistance: Because aluminum is resistant to corrosion, coatings are typically not necessary. However, if desired, specific finishes can be applied including anodizing, powder coating, paint and E-coating.
• Machinability: Aluminum is typically more machinable than iron-based castings, and it has a lower melting point.
• Versatility: Because of its versatility, aluminum is the preferred metal for many applications throughout the automotive, aerospace, marine, and outdoor products industries.

What Is The Most Commonly Used Aluminum Alloy?

Many tooling manufacturers and engineers prefer using A356 aluminum for investment castings. The characteristics of A356 aluminum include:

• Lightweight
• High Corrosion resistance
• High Ductility
• Durability
• High Strength

A356 aluminum is composed of aluminum (92.5%), copper (0.20%), iron (0.20%), magnesium (0.35%), manganese (0.10%), silicone (7%), and zinc (0.10%).

Further, A356 aluminum alloy can undergo T5 and T6 heat treatments to increase its hardness and durability. T5 heat treatments will ensure a Webster Hardness Scale (WHS) measurement of 8 to 12. Double-stepping that process with a T6 heat treatment will increase A356’s hardness to between 12 and 15 on the WHS.

Barron Industries’ Range of Aluminum Alloys

Barron Industries is an international leader in aluminum investment casting. We are a full-service manufacturer of precision machined castings, sub-assemblies, and other made-to-spec products. The most common Aluminum alloys we pour are listed in the table below, but we are capable of pouring other air melt alloys on request.

Aluminum Alloy	Tensile Strength (PSI)	Yield Strength (PSI)	% Elongation	Reference Specification	Benefits
319	23–31,000	13–20,000	1-5	ASTM B108	High weldability Corrosion resistance
355	35–50,000	28–39,000	1-3	N/A	Withstand high pressures Maintains strength at high temperatures
C355	35–50,000	28–39,000	1-3	ASTM B618 & AMS-A-21180	Withstand high pressures Maintains strength at high temperatures
356	32–40,000	22–30,000	3-7	ASTM B618AMS 4217	Good weldability Excellent mechanical properties when heat treated High strength & Ductility
A356	32–45,000	28–36,000	2-5	ASTM B618ASTM B686MIL-A-21180	Good weldability Excellent mechanical properties when heat treated High strength & Ductility
A357	38–50,000	28– 40,000	2-5	ASTM B018AMS-A-21180	Easy to cast High strength-to-weight ratio
F357	38–50,000	28–40,000	2-5	AMS 4289	Lightweight Great weldability Tolerant to many temperatures

Learn More About Aluminum Investment Casting Today

Barron Industries is a global provider of high-quality aluminum investment castings and sub-assemblies. Our extensive attention to detail and vast experience allows us to exceed the expectations of even our most demanding customers in the medical, aerospace, automotive, and defense industries.

If you have any questions about which aluminum alloy is best for your applications or want to request a quote, please reach out to our friendly team here.