Classification of forging

Forging is mainly classified according to the forming method and deformation temperature.Jiahangaero can be divided into forging and stamping according to the forming method; forging can be divided into hot forging, cold forging, warm forging and isothermal forging according to the deformation temperature.

Hot forging is forging performed above the metal recrystallization temperature. Increasing the temperature can improve the plasticity of the metal, which is conducive to improving the internal quality of the workpiece and making it less likely to crack. High temperature can also reduce the deformation resistance of metal and reduce the tonnage of forging machinery required. However, there are many hot forging processes, the precision of the workpiece is poor, the surface is not smooth, and the forging is prone to oxidation, decarburization and burning.

Cold forging is a forging performed at a temperature lower than the metal recrystallization temperature. The so-called cold forging mostly refers to forging at normal temperature, and forging at a temperature higher than normal temperature but not exceeding the recrystallization temperature is called warm forging. Forging. The precision of warm forging is higher, the surface is smoother and the deformation resistance is not large.

The workpiece formed by cold forging at room temperature has high shape and dimensional accuracy, smooth surface, less processing steps, and is convenient for automatic production. Many cold forged and cold stamped parts can be directly used as parts or products without cutting. However, during cold forging, due to the low plasticity of the metal, it is easy to crack when deformed, and the deformation resistance is large, so a large-tonnage forging machine is required.

Isothermal forging is to keep the blank temperature at a constant value during the entire forming process. Isothermal forging is to make full use of the high plasticity of certain metals at the same temperature, or to obtain specific structures and properties. Isothermal forging needs to keep the mold and blank together at a constant temperature, which requires high costs and is only used for special forging processes, such as superplastic forming.

Forging can change metal structure and improve metal performance. After the ingot is hot forged, the original cast loose, pores, microcracks, etc. are compacted or welded; the original dendrites are broken to make the grains thinner; at the same time, the original carbide segregation and unevenness are changed. Distributed to make the structure uniform, so as to obtain forgings with dense, uniform, fine, good comprehensive performance and reliable use. After the forging is deformed by hot forging, the metal is a fibrous structure; after being deformed by cold forging, the metal crystals are orderly.

The production process of forging includes forging billet blanking, forging billet heating and pretreatment before forming; heat treatment, cleaning, calibration and inspection of workpiece after forming. Commonly used forging machines include forging hammers, hydraulic presses and mechanical presses. The forging hammer has a large impact velocity, which is beneficial to the plastic flow of metal, but it will generate vibration; the hydraulic press uses static forging, which is conducive to forging through the metal and improving the structure, and the work is stable, but the productivity is low; the stroke of the mechanical press is fixed, and it is easy to realize mechanization and automation.

Jiahangaero said that the forging process in the future will improve the intrinsic quality of forging parts, develop precision forging and precision stamping technology, develop forging equipment and forging production lines with higher productivity and automation, develop flexible forging forming systems, develop new forging materials and Forging processing methods and other aspects of development.