Free Forging

Free forging, a kind of forging, utilizes impact force or pressure to make metal deformed freely in any direction between the upper and lower anvil face, without any restriction to obtain the desired shape and size as well as a certain mechanical properties. Metal parts are worked above their recrystallization temperatures, ranging from 1900°F to 2400°F for steel, and gradually shaped into the desired configuration through the skillful hammering or pressing of the work piece.
Especially for large forgings, open die forging is the only way, but is only suitable for simple shape forgings. When designing and selecting the machined parts, the free forging equipment and processes should be fully considered in order to ensure the using performance.
Free forging is divided into smith forging and mechanical hammer forging. The hand forging depends on waving hammer to forge metal into shape, while the mechanical open die forging is conducted on the basis of forging hammer or hydraulic press.

Features of Free Forging
1. The open die forging has the advantages of larger flexibility, low cost and shorter cycle production preparation.
2. Hammer forging uses universal moulds and tools, suitable for single piece and small batch production.

Application of Free Forging
Open die forging is the major production method for large forgings. This is because the hammer forging can break thick cast structure of steel ingot, forge internal porosity, shrinkage and cavities, and achieve rational distribution.

Basic Process of Free Forging
1. Swaging, also called stretching, is a forging procedure which makes the blank cross-sectional area reduced and the length increased.
2. Upsetting is to decrease the length of the semi-finished product and enlarge the cross-sectional area.
3. Punching uses plunger chip to make holes on the upsetting materials.
4. Bending adopts a tool to make the blank bent into the required shape.

Images Information

Material: C-422
Technology: Free forging
Application: 600MW subcritical reheat condensing steam turbine

Material: C-422
Technology: Open die forging
Application: 600MW subcritical steam turbine high-pressure filter-permanent filter

Material: F 91
Technology: Hammer forging
Application: High temperature and high pressure steam pipe

Material: X12CrMoWVNbN10
Technology: Free forging
Application: Subcritical steam turbine valve rod


Material: NiCr20TiAl
Technology: Open die forging
Application: 1000MW (TWCR) supercritical reheat condensing steam turbine, seal ring of high temperature and high pressure parts in main steam valve regulating

Material: C-422
Technology: Hammer forging
Application: 330MW imported subcritical reheat condensing steam turbine, high temperature and pressure regulator valve of reheat regulating valve, adjusting the air inflow to prevent overspeed operation and ensure the safe operation.

Material: NiCr20TiAl
Technology: Free forging
Application: 1000MW domestic supercritical reheat condensing steam turbine, high pressure loaded parts in main steam valve regulating


YiNuo Casting Co., Ltd. is a professional free forging manufacturer and supplier in China. Besides open die forging, we mainly offer sand casting, gravity casting, low pressure casting, centrifugal casting, ferrous metal casting and precision machined products. Our products like hammer forging process involve in many fields, such as military, high-speed rail, shipbuilding, engineering machinery, pump industry, semiconductor equipment, wind power, power station and electrical equipment.

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