When it comes to metal casting, the materials used play a crucial role in determining the quality and durability of the final product.
In other words, different metals are suitable for different applications.
Regardless of your industry, understanding the different metals used for casting is essential if you’re looking to create custom metal parts that will meet your project requirements.
In this article, we’ll explore six key metals used in metal casting, highlighting the unique characteristics of each one.
Equipped with this knowledge, you’ll be able to make better decisions about which material to use for your cast parts.
With a relatively low melting point of around 1,538 °C (2,800 °F), iron is highly suitable for casting processes.
Cast iron, in particular, exhibits exceptional castability, owing to its high carbon content and silicon composition.
This form of iron offers a range of advantages:
The following is a list of four of the most popular cast iron types used for casting custom metal parts.
The name “gray iron” comes from the material’s graphitic microstructure.
The gray color of this particular form of iron is a result of tiny flakes of graphite, which cause fractures to occur on its surface, giving it a gray appearance.
This type of iron is employed in the production of castings with complex structures and wear-resistant components.
Some examples of gray cast iron applications include manhole covers, cinder blocks, gears, hydraulic components, and pump housings.
Gray iron is the most prevalent and widely used cast iron, mainly because it is easily machinable and offers good wear resistance.
Another type of commonly used cast iron is white iron, which is prized for its wear-resistant properties.
The carbon content in white cast iron precipitates and forms large particles that enhance the hardness of its structure.
White iron finds applications in various industries, including pump housings, mill linings and rods, crushers, brake shoes, lifter bars and shell liners in grinding mills, wear surfaces of pumps, and balls and rings of coal pulverizers.
Ductile iron (also referred to as nodular cast iron, or spheroidal graphite iron) is a cast iron that has been treated with magnesium to enhance its ductility and reduce its brittleness.
It shares similar casting properties with other cast irons, such as good machinability, wear resistance, and cost-effectiveness.
Ductile iron is mostly used to produce castings with complex structures and wear-resistant parts, such as crankshafts, gears, hydraulic components, pipe fittings, and suspension components.
Malleable iron is another type of cast iron that undergoes heat treatment to increase its ductility and reduce brittleness.
Its most favorable casting property is that it is easily machinable.
The applications of malleable iron include the production of castings with complex structures and wear-resistant parts.
For example, pipe fittings, hand tools, and machinery components are often made of this material.
Each type of cast iron we’ve just discussed offers both shared and distinct characteristics that make this material, on the whole, well-suited for a wide variety of applications, ranging from complex structures to wear-resistant metal components.
Steel is an ideal material to use for castings because of its design flexibility, metallurgical versatility, and weight flexibility.
These properties make it a preferred choice for many applications across various industries.
For instance, the food processing, transportation, electronics, oil and gas, and construction industries use steel castings because they provide a variety of benefits.
These include reliability, low production costs, high degrees of dimensional accuracy, faster turnaround times, and good surface finishes.
Of all the steel grades used for castings, heat-resistant stainless steel and corrosion-resistant stainless steel are two of the most widely used.
This variety of stainless steel exhibits exceptional high-temperature strength, oxidation resistance, and formability at elevated temperatures.
Its wear-resistant properties and ability to resist large temperature variations contribute to its use in custom metal castings.
Heat-resistant stainless steel is best used for applications that require materials to withstand high temperatures, such as furnaces, heat exchangers, and incinerators.
This type of stainless steel is primarily used for cast parts when a high level of corrosion resistance is needed, ensuring the longevity of the parts produced.
Corrosion-resistant stainless steel is commonly employed in the construction of buildings, bridges, and infrastructure where exposure to harsh elements is a concern.
It is also utilized in the manufacture of kitchenware, cutlery, medical instruments, and other products that require durability.
Steel possesses excellent properties that make it an ideal material for casting, such as strength, toughness, heat, and corrosion resistance, and resistance to wear, shock, and heavy loads.
Aluminum and its derivative alloys offer a host of advantages for cast parts.
Its low melting point and viscosity when in its molten state, coupled with an ability to cool and solidify into strong, rigid solids, make aluminum a popular material selection for many casting projects.
Aluminum alloys, in particular, are often chosen for casting applications as their composition enhances the properties of base aluminum even further.
Like aluminum, these alloys possess relatively low melting points and viscosities but also provide a higher strength-to-weight ratio, ductility at lower temperatures, and stronger corrosion resistance.
Both aluminum and aluminum alloys exhibit similar properties that are required for many cast parts.
These include:
Depending on the specific alloy type and production method employed, cast aluminum can exhibit a range of characteristics, from soft and ductile to hard and brittle.
Cast aluminum and aluminum alloys find widespread usage in numerous industries.
Cookware is a prime example, as it benefits from the excellent thermal conductivity and lightweight nature of aluminum.
Other examples include the automotive and aerospace industries, where aluminum castings are employed in engine components, transmission housings, suspension parts, and aircraft components.
The versatility of aluminum and its diverse range of alloys allow for the production of complex and lightweight components that are suitable for various applications across diverse industries.
Its favorable properties, such as corrosion resistance, machinability, and weldability, further enhance its designation as a good material for metal castings.
Copper boasts remarkable properties that make it highly desirable for casting applications.
Copper’s inherent ductility and malleability allow it to be easily shaped into diverse forms.
While copper is an excellent choice for producing cast parts, copper alloys are often preferred over its purer form because of their superior mechanical properties.
The two copper alloys that are most commonly chosen for casting purposes are brass and bronze.
These two copper-based alloys are discussed in further detail below.
Brass is a combination of copper and zinc.
Not only does it possess good casting properties, such as fluidity, low shrinkage, high surface quality, and resistance to crack formation but it can also be cast into various intricate forms.
Brass alloys are typically harder and more durable than pure copper and have improved tensile strength and increased resistance to corrosion.
As such, they are often chosen for casting applications that require such properties, e.g., locks, zippers, and plumbing components.
Bronze is primarily a fusion of copper and tin but may also be augmented with other metals and substances to give it even more beneficial characteristics.
Bronze alloys are known for their enhanced versatility, strength, ductility, and corrosion resistance.
Different bronze alloys exhibit different qualities suitable for specific applications.
For instance, aluminum bronze is employed in high-stress and high-impact situations, while silicon bronze finds use in art castings, self-lubricating valves, and bearings.
Copper and its alloys, including brasses and bronzes, find extensive application in various industrial and societal contexts.
Some of the more common examples include:
Copper serves as an excellent material for castings due to its exceptional electrical and thermal conductivity, corrosion resistance, and malleability properties.
Its alloys further enhance its mechanical properties and versatility, making them even more useful for casting applications.
Nickel is regularly utilized as a material for manufacturing various industrial products.
In the realm of casting, nickel is often employed to enhance the properties of cast iron and other alloys, bringing about notable improvements in their characteristics.
Nickel alloys are often chosen over base nickel.
Some of the more common nickel alloy compositions combine nickel with other metals like tungsten, cobalt, titanium, and iron to improve corrosion and heat resistance.
Nickel-iron alloy casting is widely regarded as one of the strongest superalloys.
Notable examples of nickel alloy castings include Monel castings, Inconel castings, and Hastelloy castings, all three of which are highly valued in manufacturing for their remarkable strength and durability.
Most applications of nickel-based alloys span industries where resistance to high temperatures and corrosive operating environments are required (i.e., aerospace, marine, and chemical industries).
Nickel alloy castings shine specifically within the aerospace industry.
Their exceptional creep resistance and low expansion characteristics at elevated temperatures are necessary for many aircraft components.
Both nickel and nickel-based alloys facilitate the production of metal castings with enhanced properties.
Nickel-based alloys, in particular, offer exceptional heat resistance and corrosion resistance.
They are a popular manufacturing material across a variety of industries, with aerospace relying heavily on their exceptional properties for building critical components.
Zinc is a bluish-white metal that is used in casting because of its remarkable properties and versatile nature.
Fluidity, machinability, accuracy, stability, corrosion resistance, and recyclability are just some of the reasons why manufacturers opt for this material when casting metal parts.
Zinc also boasts a low melting point, which allows for easy handling, making it ideal for producing complex designs with high precision.
Its inherent strength also ensures durability while maintaining dimensional accuracy.
Zinc alloys, which are made primarily of zinc and other elements like aluminum, copper, and magnesium, are also renowned for their exceptional strength, durability, and corrosion-resistant properties.
During the casting process, zinc alloys are melted down and poured into molds to create intricate shapes with high precision.
By using zinc alloys as production material, manufacturers can produce complex components with fine details that would be difficult to achieve otherwise.
What is more, these alloys remain fluid when melted down, limiting the possibility of any defects or inconsistencies occurring in the final product.
Some of the most popular zinc alloys used in die casting are Zamak 2, Zamak 3, Zamak 5, and Zamak.
Since zinc and zinc alloys provide excellent corrosion resistance and durability, they are ideal materials for producing parts that are exposed to harsh environments and high temperatures.
They are widely used in the automotive industry, particularly in the production of carburetors, fuel injectors, and engine brackets.
Furthermore, zinc castings find notable use in the construction industry.
They are employed in architectural hardware like door handles, locks, and hinges due to their easy moldability properties.
Electronics and electrical equipment manufacturing also find use for them.
Their low melting point, excellent fluidity, and ability to replicate intricate details make zinc and zinc alloys a highly versatile and reliable material for numerous casting applications.
Additionally, their corrosion resistance, high strength-to-weight ratio, and cost-effectiveness further enhance their appeal as a material of choice for custom metal parts within the automotive, construction, and electronic industries.
Iron, steel, aluminum, copper, nickel, and zinc are six of the most common materials used for casting custom metal parts.
All of them provide numerous beneficial properties like malleability, design flexibility, and durability, that are advantageous for many casting applications.
Contact Bunty for Custom Casting Services
Consult an experienced metal manufacturing company like Bunty LLC to guide you in selecting the right material or alloy for your project.
Our extensive expertise will ensure a proper casting selection and a perfect final product.
Contact us through our website form or request a quote here. We welcome your inquiries.