1. isothermal forging is in the whole process of forming billet temperature to maintain a constant value. Isothermal forging is to make full use of the high plasticity of some metals at the same temperature, or to obtain specific microstructure and properties. Isothermal forging requires constant temperature of die and billet together, which requires high cost and is only used for special forging processes, such as superplastic forming.
2. forging can change the metal structure, improve the metal performance. After hot forging, the original cast loose, pores, micro-cracks and so on are compacted or welded; The original dendritic crystals are broken and the grains become fine. At the same time change the original carbide segregation and uneven distribution, make the structure uniform, so as to obtain the internal dense, uniform, fine, good comprehensive performance, reliable use of forging. After hot forging deformation, metal is fibrous tissue; After cold forging deformation, the metal crystals show order.
3. forging is to make the metal plastic flow and make the required shape of the workpiece. The volume of metal is constant after plastic flow caused by external force, and the metal always flows to the part with the least resistance. In production, the workpiece shape is often controlled according to these rules to realize upsetting drawing, hole expanding, bending, drawing and other deformation.

4. forging out of the workpiece size is accurate, conducive to mass production organization. Die forging, extrusion, stamping and other applications of mold forming size accurate, stable. High efficiency forging machinery and automatic forging production line can be used to organize professional mass production or mass production.
5. forging production process includes forging billet blanking, forging billet heating and pretreatment before forming; Heat treatment, cleaning, calibration and inspection of workpiece after forming. Commonly used forging machinery has forging hammer, hydraulic press and mechanical press. Forging hammer has a large impact speed, conducive to metal plastic flow, but will produce vibration; Hydraulic press with static forging, is conducive to forging through metal and improve the organization, stable work, but low productivity; Mechanical press stroke fixed, easy to realize mechanization and automation.
In the future, forging and pressing technology will develop to improve the internal quality of forging and pressing parts, develop precision forging and stamping technology, develop forging equipment and forging production line with higher productivity and automation, develop flexible forging and pressing system, develop new forging materials and forging processing methods. To improve the internal quality of forging parts is mainly to improve their mechanical properties (strength, plasticity, toughness, fatigue strength) and reliability. This requires a better application of metal plastic deformation theory; Application of intrinsically better quality materials; Correct pre-forging heating and forging heat treatment; More rigorous and extensive non - destructive testing of forging parts.