What Is Casting?

Casting is one of the most established processes in the metalworking sector. Despite the developments in metalforming processes, casting has maintained its relevance in the manufacture of complex-geometry parts with precise details on the surface. In order to realize the importance of casting in the field of manufacturing, it is necessary to learn the casting definition, the casting process description, and metal casting applications.

This blog describes casting as a process in manufacturing, as well as its application suitability based on the functional requirements of the end product.

What Is Casting in Manufacturing?

Casting is a technique that is used in manufacturing where liquid metal is poured into an already prepared mold and allowed to cool and solidify into a desired shape. After the solidification process, the mold is then removed, giving the manufactured product.

In technical terms, the casting definition refers to the process of working with metals, whereby the metals are subjected to a liquid state and then molded into a solid shape through the use of a mold cavity. The casting process enables the production of complex shapes and designs involving external, as well as internal, cavities.

Casting in metals is most commonly done using materials like cast iron, carbon steel, alloy steel, aluminum, brass, and bronze. The different materials can be used depending upon the conditions required, like conditions of work, loads, corrosion resistance, and dimensioning.

In an industrial manufacturing setting, casting would be preferred when the complexity of design, degree of dimensional accuracy, or surface finish is of more concern than maximum mechanical strength.

How the Casting Process Works

The casting process involves a series of carefully controlled steps to achieve accuracy. Although variations exist, some basic steps that apply to different types of casting processes have been identified.

Mold Preparation

The first stage is mold preparation. The material of molds can be sand, metal, ceramic, or composites, based on production levels. The form of the mold is designed to match the desired geometry of the part, including shrinkage during cooling.

Molten Metal Pouring

The metal is then heated in the furnace until it is molten. Once the desired composition is reached, the molten metal is poured into the mold cavity. The use of gravity or pressurized forces ensures that the liquid metal fills the cavity fully.

Cooling and Solidification

After pouring, the metal starts to cool and solidify. The rate of cooling determines the formation of the inner structure and surface finish of the final product. The mold is then removed, and the casting undergoes cleaning or finishing processes as needed after the metal is solidified.

Regarding manufacturing processes, these steps can be considered suitable for casting in order to create similar parts and shapes.

Where Casting Is Commonly Used

Casting has wide applications across various fields owing to its malleability in design and efficiency in production. It proves to be particularly effective in scenarios where:

• Complex shapes or cavities may be required
• Finely detailed surface features require accurate representation
• Near-net-shape production minimizes the amount of

Because of these properties, casting is often employed in the manufacturing of auto parts, pump housings, valves, machine bases, pipe fittings, hardware, and enclosures.

Casting has proven to be a quite efficient solution for many applications where the load acting on the structure is not very high. 

Casting vs Forging – Basic Difference

Both casting and forging belong to metal-forming processes, but they differ fundamentally in the very way the material is shaped.

• Castings are a method where molten metals are heated and cast into molds.
• Forging can be performed at elevated temperatures with compressive force to shape solid metal.
• From a structural point of view, forging usually gives a refined grain structure and higher mechanical strength, while casting allows greater freedom in design complexity.

For a detailed technical breakdown, see the full comparison here:

“Difference Between Cast and Forged Tools”

Why Casting Is Less Preferred for Load-Bearing Hand Tools

Casting retains value in many industrial applications, but as applied to professional hand tools subject to repeated mechanical stresses, it is limited.

Internal Defects

In casting, during solidification, internal porosity, shrinkage cavities, or microvoids may form. These internal defects need not necessarily be external but may compromise integrity when a structure is subjected to a load.

Lower Impact Resistance

Casting materials have a lower impact resistance property than forging materials. When it comes to actual use, tool usage can include impact loads, torsional loads, or cyclic loads to a tool, which requires a certain toughness of a tool material.

In terms of production, this means that, although casting could be applicable for some non-critical components, it might not be the most suitable option when it comes to those that function as tools and require a high degree of functionality during their use.

FAQs

1. What is casting in manufacturing?

Casting, in manufacturing, is a fabrication process by which a liquid material is poured into a mold and allowed to solidify into the shape of the mold.

2. How is casting different from forging?

While casting shapes the metal in a molten state using molds, forging forms solid metal through compressive force. Forged components normally possess higher strength and resistance to impact.

3. Is casting suitable for hand tools?

Casting is appropriate for tool components that are either non-load-bearing or very low-stress. For professional hand tools that will often see many cycles of mechanical stress, other manufacturing processes are generally preferred.

4. Why are professional tools usually forged instead of cast?

Professional tools are usually forged; this is because forging increases material strength, durability, and resistance to impact in real applications.

5. What materials are commonly used in casting?

The common materials that are used for casting include cast iron, steel, aluminum, brass, and bronze, their selection depending upon functional and environmental requirements.