Motor Information

Forging is the collective name for forging and stamping. It is a forming processing method that uses the hammer, anvil, and punch of a forging machine or a mold to exert pressure on the blank to cause plastic deformation to obtain parts of the required shape and size. .

In the forging process, the blank undergoes obvious plastic deformation as a whole, and there is a large amount of plastic flow; in the stamping process, the blank is mainly formed by changing the spatial position of each part area, and there is no large-distance plastic flow inside it. Forging is mainly used to process metal parts, and can also be used to process certain non-metals, such as engineering plastics, rubber, ceramic blanks, bricks, and the forming of composite materials.

Forging and rolling, drawing, etc. in the metallurgical industry are all plastic processing, or pressure processing, but forging is mainly used to produce metal parts, while rolling, drawing, etc. are mainly used to produce plates, strips, pipes, etc. General-purpose metal materials such as profiles and wires. Forging is the collective name of forging and stamping, just like industry and trade, also known as industry and trade.

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

hot forging

Hot forging is forging performed above the recrystallization temperature of the metal. Increasing the temperature can improve the plasticity of the metal, which is beneficial to improving the intrinsic quality of the workpiece and making it less likely to crack. High temperatures can also reduce the deformation resistance of metal and reduce the tonnage of required forging machinery. However, there are many hot forging processes, the workpiece precision is poor, the surface is not smooth, and the forgings are prone to oxidation, decarburization and burning damage. Hot forging is used when the workpiece is large and thick, and the material has high strength and low plasticity (such as roll bending of extra thick plates, drawing of high carbon steel rods, etc.). When the metal (such as lead, tin, zinc, copper, aluminum, etc.) has sufficient plasticity and the deformation is not large (such as in most stamping processes), or the total deformation is large and the forging process used (such as extrusion, When radial forging, etc.) is conducive to the plastic deformation of metal, hot forging is often not used, but cold forging is used instead. In order to complete as much forging work as possible in one heating, the temperature range between the initial forging temperature and the final forging temperature of hot forging should be as large as possible. However, if the initial forging temperature is too high, it will cause the metal grains to grow too large and cause overheating, which will reduce the quality of the forged parts. When the temperature is close to the melting point of the metal, melting of intergranular low-melting point substances and intergranular oxidation will occur, resulting in overburning. Overfired blanks tend to break during forging. Generally used hot forging temperatures are: carbon steel 800~1250℃; alloy structural steel 850~1150℃; high speed steel 900~1100℃; commonly used aluminum alloy 380~500℃; titanium alloy 850~1000℃; brass 700 ~900℃.

Cold forging

It is forging performed at a temperature lower than the recrystallization temperature of the metal. Generally speaking, cold forging refers to forging at normal temperature, while forging at a temperature higher than normal temperature but not exceeding the recrystallization temperature is called warm forging. Warm forging has higher precision, smoother surface and low deformation resistance.

Workpieces formed by cold forging at room temperature have high shape and dimensional accuracy, smooth surfaces, and few processing steps, making them easy for automated production. Many cold forged and cold stamped parts can be directly used as parts or products without the need for machining. However, during cold forging, due to the low plasticity of the metal, cracking is easy to occur during deformation and the deformation resistance is large, requiring large-tonnage forging machinery.

Warm forging

Forging at a temperature higher than normal temperature but not exceeding the recrystallization temperature is called warm forging. The metal is preheated, and the heating temperature is much lower than that of hot forging. Warm forging has higher precision, smoother surface and low deformation resistance.

Isothermal forging

The blank temperature remains constant 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 requires keeping the mold and blank at a constant temperature, which requires high costs and is only used for special forging processes, such as superplastic forming.