Heavy forgings are objects in which metal is pressed to shape the required shape or suitable compression force through plastic deformation. Strength is typically achieved by the use of a hammer or pressure. The casting process creates a refined granular structure and improves the physical properties of the metal.
According to the definition of large castings and forgings by China Forging and Pressing Association, large forgings refer to free forgings forged by hydraulic presses of more than 1000 tons and free forging hammers of more than 5 tons, and forgings produced by hot die forging equipment of more than 6000 tons and die forging hammers of more than 10 tons. Products with high comprehensive performance requirements, complex processes and special customization are mainly used to manufacture key and important parts of major equipment, such as steam turbine spindles and rotors, marine forgings and metallurgical rolls.
Large forgings are divided into large die forgings, large free forgings, rings and large diameter thick wall seamless pipe fittings. The free forgings produced with a 1000 ton or more free forging hydraulic press or a 3 ton or more free forging hammer are large free forgings. The die forgings produced by more than 6000 tons of die forging presses, more than 8000 tons of die forging hydraulic presses or more than 10 tons of die forging hammers are large die forgings. Large forgings have strict requirements for internal quality, and the production technology is difficult.
