Model forging is a method in which metal is plastically deformed under the action of external force and fills the die cavity to obtain forgings.
Commonly used die forging equipment includes die forging hammer, hot die forging press, flat forging machine and friction press.
Compared with free forging, die forging has high dimensional accuracy, small machining allowance, and more reasonable distribution of fiber structure, which can further improve the service life of parts. Die forging has high productivity, simple operation, and easy mechanization and automation. However, the equipment investment is large, the forging die cost is high, the production preparation period is long, and the quality of the die forging is limited by the tonnage of the die forging equipment, so it is suitable for batch and mass production of medium and small forgings (generally <150 kg).
During free forging, the shape of the product is simple, and it is directly forged in a friction press. Only part of the metal surface is in contact with the tool or anvil, and the rest is a free deformation surface. Common dies and tools are used in free forging, which has high flexibility, low cost, and short production preparation cycle, and is suitable for single-piece and small-batch production. However, the productivity of free forging is low, the labor intensity of workers is high, the precision of forgings is poor, and the machining allowance is large. Therefore, the proportion of free forgings in the total forgings is decreasing with the advancement of production technology. Free forging is also the main production method for large forgings, and occupies an important position in the heavy metallurgical machinery, power machinery, mining machinery, crushing machinery, forging machinery, ships and locomotive manufacturing industries.