Types of Forging Process

Forging can be divided into free forging, die forging, rolling ring, special forging.

1. Free forging. Refers to the processing method of forgings that use simple universal tools or directly apply force to the billet between the upper and lower anvils of the forging equipment to deform the billet to obtain the desired geometry and internal quality. Forgings produced by free forging are called free forgings. Free forging is mainly based on forgings with a small production volume. Forging equipment such as forging hammers and hydraulic presses are used to form the blanks to obtain qualified forgings. The basic processes of free forging include upsetting, lengthening, punching, cutting, bending, twisting, shifting and forging. Free forging adopts hot forging method.

2. Die forging. Die forging is divided into open die forging and closed die forging. The metal blank is compressed and deformed in a forging die cavity with a certain shape to obtain a forging. Die forging is generally used to produce parts with small weight and large batches. Die forging can be divided into hot die forging, warm forging and cold forging. Warm forging and cold forging are the future development direction of die forging, and also represent the level of forging technology.

Extrusion should belong to die forging, which can be divided into heavy metal extrusion and light metal extrusion.

Closed die forging and closed upsetting are two advanced processes of die forging. Since there is no flash, the material utilization rate is high. With one process or several processes, it is possible to finish the finishing of complex forgings. Since there is no flash, the bearing area of the forging is reduced, and the required load is also reduced. However, it should be noted that the blank cannot be completely restricted. For this reason, the volume of the blank should be strictly controlled, the relative position of the forging die and the measurement of the forgings should be controlled to reduce the wear of the forging die.

3. Grinding ring. Rolling ring refers to the production of ring parts of different diameters by special equipment ring rolling machine, and is also used to produce wheel-shaped parts such as automobile wheels and train wheels.

4. Special forging. Special forging includes roll forging, cross wedge rolling, radial forging, liquid die forging and other forging methods. These methods are more suitable for the production of parts with special shapes. For example, roll forging can be used as an effective pre-forming process to greatly reduce the subsequent forming pressure; cross wedge rolling can produce steel balls, transmission shafts and other parts; radial forging can produce large forgings such as barrels and step shafts.