White Paper: Types of Investment Casting Materials

Investment casting has been used for ages to produce a wide variety of parts and prototypes. However, the most significant thing is about choosing the right investment casting material for your project. A suitable precision casting material helps you achieve the desired functionality while saving costs and reducing casting defects.

With investment casting, the final pieces often come with a smooth surface finish and dimensional precision. Accordingly, the process allows for lower weight and thin walls. However, it is the choice of material that determines the properties you get in your products.

Types of Investment Casting Materials

One of the benefits of investment casting is that it allows precision casting manufacturers to produce a wide range of products using both ferrous and non-ferrous metals and metal alloys. Some of the investment casting materials that can be used include:

·        Stainless Steel

Stainless steel is used in investment casting because of its superior durability compared to other materials. Additionally, stainless steel has the potential that makes it suitable for various investment casting products. Examples of investment casting products made of stainless steel include furnaces, golf club heads, and gearboxes.

·        Steel Alloys

Alloys of steel with not less than 10.5% chromium offer excellent machinability with desirable features, such as corrosion and wear resistance. Additionally, steel alloys are physically appealing. Investment casting products made of steel alloys include hinge assemblies, agricultural equipment, and ball valve parts.

·        Low Alloy Steel

Low alloy steels are the most used investment casting materials. This is mainly due to their affordability and other advantages.

Investment casting manufacturers can make various parts with different properties. For instance, engineers can use varying heat treatments to make a surface strong and resistant to impact and another surface resistant to wear.

·        Titanium Alloy

Investment casting uses titanium alloys when the fabricated part requires high fracture toughness and metallurgical integrity. For instance, this material is mainly used to manufacture gold club heads.

·        Cast Aluminum

Cats aluminum is used to manufacture a wide range of investment casting products, such as investment casting cookware and investment casting automotive parts. Other products include pistons, radiator tanks, compressors, and gears.

Cast aluminum is created through different casting processes. One of the benefits of cast aluminum as an investment casting material is that it is cost-efficient compared to most materials. Additionally, cast aluminum is relatively durable. However, it is not as durable as cast iron.

·        Aluminum Alloys

Aluminum alloy is a very popular investment casting material. This material is used widely in the aerospace, military, avionic, and electronics industries.

Aluminum alloy is used widely in investment casting due to its enhanced material strength and quality.

·        Carbon Steel

Carbon steel is a very popular low-cost investment casting material that comes in many grades and classifications, depending on the percentage of carbon content. Carbon steel is strong, ductile, and offers high performance that improves various industrial applications. Additionally, carbon steel posses ferromagnetic properties that make it suitable for manufacturing motors and other electronics. Additionally, carbon steel is one of the safest, durable investment casting materials with high structural integrity.

·        Super Alloy

Superalloys are mainly based on cobalt and nickel. These alloys are very common in the aerospace, energy, medical, and marine industries. Alloys based on nickel are excellently stronger at higher temperatures. On the other hand, alloys based on cobalt are highly wear, oxidation, and corrosion-resistant.

Superalloys are used in place of plate sheets because they possess high rigidity and better service properties.

·        Copper Alloy

Alloys of copper are mainly resistant to corrosion and do not wear out easily. Copper-based alloys are mainly used in manufacturing investment casting products, such as pump propellers.

Additionally, copper is a highly versatile material with more than 400 alloys, making it suitable for various applications.

Copper-based alloys can be used to manufacture different investment casting parts. Some of the widely used copper-based alloys include brass and bronze. Additionally, beryllium-copper is the strongest of copper alloys, and it also possesses higher corrosion resistance.

·        Brass and Bronze

Brass and bronze are copper-based alloys with excellent machinability and corrosion resistance. These investment casting materials are non-sparking and offer excellent aesthetic appearances.

Investment casting companies used brass and bronze to manufacture cast products with tight tolerance and outstanding repeatability. The most common parts include impellers, pump parts, and hinge assemblies.

·        Cast Iron

Cast iron is known for its affordability and high precision. Ductile iron comes with excellent strength and heat resistance. However, it requires more complex processes, which may lead to added costs.

Investment Casting Materials for Minimizing Porosity

Some investment casting materials are better at minimizing porosity without post-processes. However, investment casting manufacturers usually use heat treatment to reduce porosity. For instance, aluminum alloys require secondary shrinkage methods to make the manufacturing process more manageable. When this is not done, bubbles form on the surface of the finished piece since the material is highly soluble in hydrogen. Therefore, it may require secondary processes to reduce porosity in the final product.

Investment Casting Materials for Thin Walls

The most suitable investment casting material for thin walls is aluminum. Steel alloys with sulfur are also excellent. However, any material can be used to achieve thin walls.

Investment Casting Materials for Painting and Plating

Any investment casting material can be painted. However, the best and easiest to paint are alloys that are resistant to oxidation. For instance, painting stainless steel can be a challenge unless you use secondary thermal processes. On the other hand, painting steel alloys with low carbon content is very straightforward.

Another factor that may determine the ease of plating and painting is surface finish. Generally, parts with a very smooth surface finish may be hard to paint.

The Bottom Line

Investment casting is a versatile method of metal fabrication because it can use various materials in the process.

Whether you want a corrosion-resistant part or material with improved tensile strength and ductility, you can always find one that can be investment cast to meet your requirements. Various investment casting manufacturers use different types of investment casting materials to achieve desired specifications.

With the ability to cast metal components of different sizes, investment casting offers dynamic solutions for every customer.