Forging is one of the important methods for plastic forming of metal materials, and it occupies an important position in the current manufacturing industry. The internal structure of the forging is fine and uniform, the mechanical properties are good, and the service life of the parts is high. The forging production has the characteristics of high labor productivity, small machining allowance of the forged blank formed, high material utilization, and material saving. Cycling, aerospace, marine, military, instrumentation, electrical appliances, chemical, daily hardware and other industrial sectors.
According to the characteristics of metal plastic forming, metal plastic processing is generally divided into two types: volume forming and sheet forming. Each type of forming method includes various processing methods to form its own process area.
First, volume forming
In the process of volume forming, it is realized by the transfer and distribution of the blank volume during the plastic deformation process. This type of forming can be divided into primary processing and secondary processing.
1. One-time processing
Primary processing is a processing method used by the metallurgical industry to produce pipes, plates, rods, wires, and profiles. The main methods of plastic processing include rolling, extrusion, and drawing. In this type of forming process, the shape of the metal deformation zone is constant over time, which is a stable deformation process, which is suitable for mass production. Generally, the products of large steel mills are mainly processed at one time, and various shapes can be produced in one process.
2. Secondary processing
Second processing is a processing method that provides parts or blanks for the mechanical manufacturing industry. Such processing methods include free forging, die forging and special forging, which are generally referred to as forging, and mainly include the following forming methods.
Free forging. Free forging is the upsetting, drawing, punching, reaming of ingots or rods with simple tools such as hammers, anvils, anvils, plungers, punches, pads, etc. on a forging hammer or press. , Bending and other operations, processing methods to produce parts or blanks. Free forging is characterized by large machining allowance and low production efficiency. The mechanical properties and surface quality of forgings are greatly affected by the technical level of free forging operators. Free forging is suitable for forging of single piece, small batch and large forging. According to the quality of the forging, free forging equipment such as air hammer, steam · air hammer or hydraulic press can be used.
When free forging, it can also be forged with the help of a simple die, which is called tire die forging. Tire forging is a method of producing forgings using a movable die on a free forging equipment. It is a forging method between free forging and die forging. The shape and size of the forging are guaranteed by the tire mold. Therefore, the tire mold forging has high dimensional accuracy, uniform deformation, reasonable streamline distribution, high forging surface quality, and high forging efficiency. It can forge more complex forgings and tire mold segments. It is through manual mold removal and turning, and the labor intensity of the operator is greater during forging.
Die forging. Die forging is a processing method of placing a metal blank in a mold cavity with a certain shape and size on the forging machine to plastically deform it under the impact of a forging hammer or pressure to obtain a forging or part with the same shape and size as the cavity. The upper and lower modules of the forging die are respectively fastened on the hammer head and the anvil, and the machining allowance of the die forging is small, requiring only a small amount of machining or no machining. Die forging can be divided into open die forging and closed die forging. Because metal forming is formed in a certain cavity, the shape and size of the forging is high, the production efficiency is high, the internal structure of the forging is uniform, and the range of the performance change between the forging and the forging is small. The shape and size of the forging mainly depend on the mold. It is ensured that it is less affected by the technical level of the forging operator. The commonly used equipment for die forging include die forging hammer, crank press, hydraulic press, and flat forging machine. Die forging production must rely on two die forging equipment and molds. For die forging on crank presses and hydraulic presses, it is often necessary to configure equipment such as free forging or roll forging to make blanks. The investment cost of die forging equipment is large, it is not suitable for the production of single-piece and small batch forgings, and is suitable for the production of large-volume or mechanized forgings.
Special forging Some forgings can be greatly improved with special equipment forging, and the size, shape and performance of forgings can be better guaranteed. For example, the production of screws and bolts using a hoe and a thread rolling machine has doubled the production efficiency. Using swing rolling to produce discs or cups can save equipment tonnage. Rotating forging produces rods with high surface quality W, higher production efficiency and convenient operation. Special forging has certain limitations. Its forging equipment can only produce a certain type of product, so it is suitable for the production of large-scale forgings or parts.