yvonne@nydcasting.com 
Casting is a long-established metalworking method that involves injecting molten metal into a mold, where it cools and solidifies into a desired shape. The selection of casting materials is critical to ensure casting quality, productivity and performance of the finished product. This paper discusses the types, characteristics, and applications of casting materials to help readers understand their selection and alignment with actual needs.
1. Types of Casting Materials
First, the classification of casting materials
Casting materials can be roughly divided into two categories: metal casting materials and non-metallic casting materials. Metal casting materials are the most widely used materials in the foundry industry, mainly including cast iron, aluminum alloys, copper alloys, steel alloys and so on. The non-metallic casting materials include some special casting sand, paint and synthetic resin. Below, we will focus on several major types of metal casting materials and their characteristics.
1). Cast iron
Cast iron is a common casting material, which is widely used because of its ease of casting, good fluidity and low cost. The main component of cast iron is iron, containing a certain percentage of carbon, usually between 2% and 4% carbon content. According to the different alloying elements, cast iron can be divided into a variety of types, common gray cast iron, ductile iron and malleable cast iron.
- Gray cast iron: gray cast iron has good castability and processability, because of its graphite flake distribution, so it has good vibration damping and wear resistance, widely used in engine block, machine tool bed and other fields.https://nydcasting.com/grey-iron-casting/
- Ductile Iron: By adding the spheroidal distribution of graphite through the addition of a spheroidal agent, thereby improving its strength and toughness. Ductile iron has higher tensile strength, impact resistance and fatigue resistance than gray cast iron, commonly used in automotive parts, pipelines and so on.https://nydcasting.com/ductile-iron-casting/
- Malleable cast iron: malleable cast iron after heat treatment has good malleability, can be processed into a tougher material than steel, widely used in high-strength requirements of mechanical components.
2). Aluminum alloy
Aluminum alloy is lightweight, corrosion-resistant, and easy to cast, making it widely used in aviation, automotive, and electronics. Its casting process is simple, using methods like sand casting and die casting to create complex parts.
Common aluminum alloys include aluminum-silicon alloy, aluminum-copper alloy, aluminum-magnesium alloy and so on. Aluminum-silicon alloys are widely used in automobile engine blocks, ships, aircraft parts and other fields because of their excellent castability and corrosion resistance. Aluminum-copper alloy is usually used for demanding mechanical parts because of its high strength and high hardness.
3). Copper alloy
Copper alloys are essential casting materials known for their excellent electrical conductivity and corrosion resistance. They are used in industries such as electrical, electronics, and construction. The casting process for copper alloys is complex, requiring careful control of temperature and alloy composition to ensure the desired properties.
Copper alloys mainly include bronze, brass and aluminum bronze. Bronze has good corrosion and wear resistance, and is often used to make mechanical parts, coins and so on. Brass, on the other hand, has good workability and high strength, and is widely used in pipes, valves and other equipment.
4). Iron and steel alloys
Iron and steel alloys are the main materials for making heavy machinery and structural parts. By changing the proportion of alloying elements, different properties of steel alloys can be obtained to meet various industrial needs. Common steel alloys are carbon steel, alloy steel, stainless steel and so on.
- Carbon steel: Carbon steel is the most common casting material, low cost, good strength and weldability, widely used in machinery manufacturing, building structures and other fields.https://nydcasting.com/carbon-steel-casting/
- Alloy steel: alloy steel by adding chromium, nickel, molybdenum and other alloying elements, to obtain higher strength, toughness and wear resistance, commonly used in the manufacture of mechanical parts requiring high strength and wear resistance.
- Stainless steel: Stainless steel contains a high proportion of chromium, has excellent corrosion resistance, widely used in the chemical industry, food processing, medical equipment and other fields.https://nydcasting.com/stainless-steel-casting/
2. Selection of casting materials
Choosing the right casting material depends on several factors, including product requirements, operating conditions, and production processes. The following are a few major factors to focus on when choosing casting materials:
Strength and hardness: The strength and hardness of casting materials directly impact the part’s service life and performance. For high-load engine parts, high-strength cast iron or aluminum alloy ensures stability, while wear-resistant parts benefit from materials like ductile cast iron with high hardness.
Corrosion resistance: For parts in harsh environments (e.g., marine equipment, chemical containers), corrosion resistance is crucial. Materials like aluminum alloy and stainless steel, known for their excellent corrosion resistance, are ideal for ensuring durability over time.
Castability: Castability refers to the material in the casting process is easy to mold and not easy to produce defects in the characteristics. Some materials such as cast iron and aluminum alloys have good castability, suitable for the manufacture of complex shapes and sizes of parts. While some high-strength materials such as steel alloys, its castability is poor, requiring special casting process.
Cost-effectiveness: Cost is an important factor that must be considered when choosing casting materials. Material costs vary, with cast iron being cheaper and aluminum or copper alloys more expensive. Companies must balance performance and cost to meet technical and economic requirements.
Environment and sustainability: As environmental awareness increases, sustainability has become an important consideration in material selection. Aluminum alloys and copper alloys, are becoming more and more popular due to their lower environmental impact and good recyclability. As new technologies like 3D printing develop, casting materials are also becoming more eco-friendly and sustainable.
3. Future trends
With the continuous progress of science and technology, the research and application of casting materials continue to change. Here are some future trends in casting materials:
- Research and development of high-performance alloys: In order to meet the aerospace, automotive, energy and other industries on the material’s high strength, high temperature resistance, corrosion resistance and other performance needs, the future will continue to research and development of new high-performance alloy materials. These alloys will have better overall performance and can adapt to more demanding working environment.
- Green and Sustainable Materials: With the continuous improvement of environmental protection requirements, the foundry industry will pay more attention to the development of green casting materials. For example, low emissions, low energy consumption casting process and recyclable materials will become the future direction of development.
- Intelligent and digital casting materials: with the development of intelligent and digital technology, the future of casting materials will be more intelligent, able to adjust the production process and material ratios according to real-time monitoring data, thereby improving production efficiency and product quality.
4. Conclusion
Casting materials play a crucial role in modern industries. Different materials have unique advantages and applications depending on the requirements of the product and the operating conditions. With ongoing technological advancements, the selection and use of casting materials will continue to evolve, leading to more efficient, precise, and sustainable casting processes. By selecting the appropriate materials, industries can ensure high-quality products that meet the ever-growing demands of various sectors.