Forging can be classified according to the following methods:

1. Classify according to the placement of forging tools and molds.

2. Classified by forging forming temperature.

3. Classify according to the relative motion mode of forging tools and workpieces.

The preparation before forging includes raw material selection, material calculation, cutting, heating, calculation of deformation force, equipment selection, and mold design. Before forging, it is necessary to choose a good lubrication method and lubricant.

Forging materials cover a wide range, including various grades of steel and high-temperature alloys, as well as non-ferrous metals such as aluminum, magnesium, and copper; There are both rods and profiles of different sizes processed once, as well as ingots of various specifications; In addition to extensively using domestically produced materials suitable for our country's resources, there are also materials from abroad. Most of the forged materials are already listed in national standards. There are also many new materials that have been developed, tested, and promoted. As is well known, the quality of products is often closely related to the quality of raw materials. Therefore, forging workers must have extensive and in-depth knowledge of materials and be good at selecting the most suitable materials according to process requirements.

Material calculation and cutting are important steps in improving material utilization and achieving refined blanks. Excessive material not only causes waste, but also exacerbates mold wear and energy consumption. If there is not a slight margin left during cutting, it will increase the difficulty of process adjustment and increase the scrap rate. In addition, the quality of the cutting end face also has an impact on the process and forging quality.

The purpose of heating is to reduce forging deformation force and improve metal plasticity. But heating also brings a series of problems, such as oxidation, decarburization, overheating, and overburning. Accurately controlling the initial and final forging temperatures has a significant impact on the microstructure and properties of the product. Flame furnace heating has the advantages of low cost and strong adaptability, but the heating time is long, which is prone to oxidation and decarburization, and the working conditions also need to be continuously improved. Induction heating has the advantages of rapid heating and minimal oxidation, but its adaptability to changes in product shape, size, and material is poor. The energy consumption of heating process plays a crucial role in the energy consumption of forging production and should be fully valued.

Forging is produced under external force. Therefore, the correct calculation of deformation force is the basis for selecting equipment and conducting mold verification. Conducting stress-strain analysis inside the deformed body is also essential for optimizing the process and controlling the microstructure and properties of forgings. There are four main methods for analyzing deformation force. Although the principal stress method is not very rigorous, it is relatively simple and intuitive. It can calculate the total pressure and stress distribution on the contact surface between the workpiece and the tool, and can intuitively see the influence of the aspect ratio and friction coefficient of the workpiece on it; The slip line method is strict for plane strain problems and provides a more intuitive solution for stress distribution in local deformation of workpieces. However, its applicability is narrow and has been rarely reported in recent literature; The upper bound method can provide overestimated loads, but from an academic perspective, it is not very rigorous and can provide much less information than the finite element method, so it has been rarely applied recently; The finite element method can not only provide external loads and changes in the shape of the workpiece, but also provide the internal stress-strain distribution and predict possible defects, making it a highly functional method. In the past few years, due to the long computation time required and the need for improvement in technical issues such as grid redrawing, the application scope was limited to universities and scientific research institutions. In recent years, with the popularity and rapid improvement of computers, as well as the increasingly sophisticated commercial software for finite element analysis, this method has become a basic analytical and computational tool.

Reducing friction can not only save energy, but also improve the lifespan of molds. One of the important measures to reduce friction is to use lubrication, which helps improve the microstructure and properties of the product due to its uniform deformation. Due to different forging methods and working temperatures, the lubricants used are also different. Glass lubricants are commonly used for forging high-temperature alloys and titanium alloys. For hot forging of steel, water-based graphite is a widely used lubricant. For cold forging, due to high pressure, phosphate or oxalate treatment is often required before forging.