1. Process principle 

Casting is a process in which metal is melted into liquid and then solidified in a mold of a specific shape by casting, solidification, cooling and other means. During the casting process, the fluidity of the molten metal allows it to fill every corner of the mold, thus forming a complex shape. In addition, casting can also adjust the composition and temperature of the molten metal, as well as the material and shape of the mold, to achieve the regulation of product performance.

Forging is a processing method that uses a forging machine to apply pressure to the metal billet to cause it to undergo plastic deformation to obtain forgings with certain mechanical properties, shapes and sizes. During the forging process, the grain structure of the metal billet changes under the hammering or pressure of the forging machine, thereby improving the density and mechanical properties of the metal. Compared with casting, forging can make the metal reach its optimal mechanical properties.

2. Product performance

The advantage of cast products is that they can form complex shapes and have relatively low production costs. However, due to the solidification shrinkage of the molten metal during the casting process and the limitations of the mold, cast products often have defects such as shrinkage cavities, shrinkage porosity, and pores. In addition, the mechanical properties of cast products are usually lower than those of forged products because their internal grain structure is coarse and uneven.

In contrast, forged products have higher mechanical properties and more uniform internal organization. The plastic deformation of the metal during forging can eliminate its internal defects, while refining the grains and increasing its density. Therefore, forged products usually have higher strength, toughness and wear resistance. However, the shape of forged products is relatively simple and the production cost is relatively high.

3. Application fields

Casting and forging also differ in their application fields. Casting is widely used in the manufacture of complex parts such as automobile engine blocks, machine tool beds, pipeline valves, etc. due to its ability to form complex shapes. In addition, casting also plays an important role in the manufacture of artworks and jewelry.

Forging is more suitable for the manufacture of parts that withstand high loads and high impact forces, such as turbine blades for aircraft engines, axles for high-speed trains, propellers for large ships, etc. These parts have extremely high requirements on the mechanical properties and internal organization of the material, so forging has become the preferred processing technology.

4. Environmental protection and resource utilization

In terms of environmental protection and resource utilization, casting and forging also have their own advantages and disadvantages. A large amount of waste slag and waste gas will be generated during the casting process, causing certain pollution to the environment. However, with the continuous advancement of environmental protection technology and the improvement of casting technology, modern casting has achieved effective treatment and recycling of waste slag and waste gas.

Although no waste slag and waste gas will be generated during the forging process, its utilization rate of metal raw materials is relatively low. In order to improve resource utilization and reduce costs, modern forging technology is constantly exploring and optimizing the shape and size of the billet and the performance and parameters of the forging machinery.

In summary, casting and forging, as the two core technologies of metal processing, have significant differences in process principles, product performance, and application areas. Understanding these differences will help us better select and use these two technologies to meet different production needs and social needs.