Forging is a processing method that uses forging machinery to apply pressure to metal blanks to produce plastic deformation to obtain forgings with certain mechanical properties, certain shapes and sizes. Forging (forging and stamping) is one of the two major components. Forging can eliminate the defects such as loose casting in the smelting process and optimize the microstructure. At the same time, due to the preservation of the complete metal flow line, the mechanical properties of forgings are generally better than castings of the same material. Related machinery in high load, severe working conditions of important parts, in addition to the shape of a relatively simple available rolling plates, profiles or weldments, the use of forgings.

1. Deformation temperature

The beginning of the recrystallization temperature of steel is about 727 ℃, but commonly used 800 ℃ as a dividing line, higher than 800 ℃ is hot forging; between 300~800 ℃ is called warm forging or semi-hot forging, forging at room temperature is called cold forging. Forgings used in most industries are hot forging, warm forging and cold forging are mainly used for automobile, general machinery and other parts of the forging, warm forging and cold forging can effectively save material.

2. Forging category

As mentioned above, according to the forging temperature, it can be divided into hot forging, warm forging and cold forging. According to the forming mechanism, forging can be divided into free forging, die forging, grinding ring, special forging.

1) Free forging

Refers to the processing method of forging parts that use simple universal tools or directly apply external force to the blank between the upper and lower anvils of the forging equipment to deform the blank to obtain the required geometric shape and internal quality. Forgings produced by the free forging method are called free forgings. Free forging is based on the production of small quantities of forgings, the use of forging hammers, hydraulic presses and other forging equipment for the blank forming processing, to obtain qualified forgings. The basic processes of free forging include upsetting, drawing, punching, cutting, bending, twisting, shifting and forging. Free forging is hot forging.