Four types of forgings

According to the forming mechanism, forging can be divided into free forging, die forging, rolling ring, and special forging.

1. Free forging. Refers to a method of processing a forging that uses a simple universal tool or an external force directly applied to the blank between the upper and lower anvil of the forging equipment to deform the blank to obtain the desired geometry and internal quality. Forgings produced by the free forging method are called free forgings. Free forging is mainly for the production of forgings with small quantities, and forgings are processed by forging equipment such as forging hammers and hydraulic machines to obtain qualified forgings. The basic processes of free forging include upsetting, lengthening, punching, cutting, bending, twisting, misalignment and forging. Free forging is a hot forging method.

2, die forging. Die forging is divided into open die forging and closed die forging. The metal blank is subjected to compression deformation in a forging die having a certain shape to obtain a forged piece, and the die forging is generally used for producing a part having a small weight and a large batch size. Die forging can be divided into hot forging, warm forging and cold forging. Warm forging and cold forging are the future development directions of die forging, and also represent the level of forging technology.

According to the material, die forging can also be divided into black metal die forging, non-ferrous metal die forging and powder product forming. As the name implies, the materials are ferrous metals such as carbon steel, non-ferrous metals such as copper and aluminum, and powder metallurgy materials.

Extrusion should be attributed to die forging and can be divided into heavy metal extrusion and light metal extrusion.

Closed die forging and closed upset forging are two advanced processes for die forging. Since there is no flash, the material utilization rate is high. Finishing of complex forgings is possible with one or several processes. Since there is no flash, the area of force applied to the forging is reduced and the required load is also reduced. However, care should be taken not to completely limit the blank. To this end, the volume of the blank is strictly controlled, the relative position of the forging die is controlled, and the forging is measured to reduce the wear of the forging die.

3, grinding ring. Rolling ring refers to the production of ring-shaped parts of different diameters by special equipment grinding machine, and 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, etc. These methods are more suitable for the production of parts with special shapes. For example, roll forging can be used as an effective preforming process to significantly reduce subsequent forming pressures; cross wedge rolling can produce steel balls, drive shafts, etc.; radial forging can produce large forgings such as barrels and step shafts.