Casting, an essential technology in the manufacturing industry, is widely used in the production of various metal products. The basic principle involves heating metal materials to a liquid state and pouring them into molds to form the desired shape. After cooling and solidifying, the castings are obtained. The casting process is crucial due to its high production efficiency, low cost, and ability to manufacture complex-shaped components, making it indispensable in various fields.
Metal casting is an ancient manufacturing process that involves heating metal to a liquid state, pouring it into molds, and allowing it to cool and solidify into the required shape. The dimensions, shape, and structure of castings can be adjusted according to design requirements, making it suitable for both complex and mass production. Casting processes are not only applicable to various metal materials, especially common metals such as copper, iron, aluminum, tin, lead, and steel, but also enable the production of high-performance alloys through alloying techniques, which are used in different industries.
Common casting materials include gray cast iron, ductile cast iron, cast steel, aluminum alloys, magnesium alloys, and copper alloys. These materials are widely used in industries such as automotive, aerospace, shipbuilding, machinery manufacturing, power, and chemicals, due to their excellent mechanical properties, corrosion resistance, and machinability.
Casting processes have evolved into several types based on production requirements, casting characteristics, and material properties. Each process has its unique advantages and applicable fields. Below are several common casting processes, along with their characteristics and applications.
Sand casting is the most common and historically established method. In this process, molten metal is poured into a mold made of sand and binder, which solidifies and forms the casting. Sand casting is suitable for large, low-volume, or complex-shaped castings.
Suitable for various metal materials, particularly cast iron and steel.
Can produce large and complex parts, making it ideal for large mechanical components.
Low cost, with simple mold preparation.
The surface finish is relatively rough and requires post-processing to improve surface quality.
Accuracy is lower, making it suitable for castings with lower precision requirements.
Sand casting is widely used for automotive engine blocks, mechanical components, and construction equipment.
Investment casting (also known as lost wax casting) is a precision casting method often used for complex-shaped parts. The process involves creating a wax pattern of the casting, coating it with refractory material to form a mold, and then melting away the wax before pouring molten metal into the mold.
Can produce complex, high-precision castings.
Smooth surface and high dimensional accuracy, requiring minimal post-processing.
Suitable for aerospace, precision instruments, and jewelry manufacturing.
Complex process with a longer production cycle.
Best suited for small batch production, with relatively high costs.
Investment casting is commonly used for aerospace engine components, medical devices, precision tools, and art objects.
Die casting involves injecting molten metal under high pressure into precision molds, which are then rapidly cooled and formed. This method is ideal for mass production of small, complex, and precise castings, particularly in aluminum, zinc, and magnesium alloys.
High production efficiency, suitable for large-volume production.
Smooth surface finish and high dimensional accuracy, requiring minimal subsequent processing.
Enables automated production, reducing labor costs.
Relatively high cost, making it suitable for castings with specific production scale requirements.
High equipment requirements, with mold size limitations.
Die casting is widely used in industries such as automotive, home appliances, electronics, and telecommunications.
Shell mold casting involves coating a metal mold with a layer of refractory material to form a strong outer shell. Once the shell solidifies, molten metal is poured into it to form the casting. Shell mold casting offers higher precision and is typically used for small batches of high-precision components.
High precision with smooth surfaces and stable dimensions.
Suitable for casting complex-shaped parts.
High production efficiency and good casting quality.
Relatively high cost, making it suitable for high-end markets or small batch production.
Requires high equipment and operator skill levels.
Shell molding is commonly used for producing precision mechanical parts and aerospace components.
Centrifugal casting involves pouring molten metal into a rapidly rotating mold, where centrifugal force distributes the metal and forms a dense, high-quality casting. This process is particularly suitable for producing pipes, rings, and other castings requiring high mechanical properties.
High density and excellent surface quality, with reduced defects.
Suitable for large-volume production, particularly for circular castings.
Ideal for manufacturing wear-resistant, corrosion-resistant, and high-strength castings.
Not suitable for complex-shaped castings, typically used for simple circular or pipe shapes.
High mold requirements, with a more complex production process.
Centrifugal casting is widely used for producing pipes, wheels, engine blocks, and other products.
As a fundamental manufacturing technology, casting plays a critical role in modern industry. From traditional sand casting to advanced die casting and investment casting, as well as the emerging intelligent and eco-friendly casting technologies, each casting method has its own features, making it suitable for different production needs. When selecting the appropriate casting process, factors such as product shape, size, precision, production volume, material properties, and cost must be considered. With continuous advancements in technology, casting processes will continue to evolve in terms of precision, efficiency, and environmental sustainability, driving modern manufacturing toward more efficient and sustainable practices.
