Definition and Classification of Forging

Forging is a processing method that uses forging machinery to apply pressure to metal blanks to produce plastic deformation to obtain forgings with certain mechanical properties, certain shapes and sizes. Forging (forging and stamping) is one of the two major components.

Classification of forging according to different production tools

According to different production tools, forging technology can be divided into free forging, modular forging, ring rolling and special forging.

Free forging: refers to the processing method of forgings that uses simple general-purpose tools or directly apply external force to the blank between the upper and lower anvils of the forging equipment to deform the blank to obtain the required geometric shape and internal quality.

Die forging: refers to the forging of metal blanks that are compressed and deformed in a forging die with a certain shape. Die forging can be divided into hot die forging, warm forging and cold forging.

Ring rolling: refers to the production of ring parts with different diameters through special equipment ring rolling machines, which are also used to produce wheel-shaped parts such as automobile hubs and train wheels.

Special forging: including roll forging, cross wedge rolling, radial forging, liquid die forging and other forging methods, these methods are more suitable for the production of some special shapes of parts.

Classification of forging according to the forging temperature

According to the forging temperature, the forging technology can be divided into hot forging, warm forging and cold forging.

The initial recrystallization temperature of steel is about 727°C, but 800°C is generally used as the dividing line, and the temperature higher than 800°C is hot forging; the temperature between 300 and 800°C is called warm forging or semi-hot forging, which is forged at room temperature. It is called cold forging. Forgings used in most industries are hot forging. Warm forging and cold forging are mainly used for forging parts of automobiles and general machinery. They can effectively save materials.

According to the movement mode of the forging die, forging can be divided into swing rolling, swing swivel forging, roll forging, cross wedge rolling, ring rolling and cross rolling.

Forging materials

The forging materials are mainly carbon steel and alloy steel with various compositions, followed by aluminum, magnesium, copper, titanium, etc. and their alloys. Iron-based superalloys, nickel-based superalloys, cobalt-based superalloys and deformed alloys are also completed by forging or rolling, but these alloys are relatively difficult to forge due to their relatively narrow plastic zone. The heating temperature, opening forging temperature and final forging temperature of different materials have strict requirements.