what is forging?
Die Forging is the process of plastically deforming solid metal (never molten) from one shape into another shape, between two dies, under very high pressure. During this process, the aluminum is forced to conform to the configuration of the cavity in the dies. The advantages of a forging over other methods of manufacturing include optimum grain structure and fatigue life, superior stress and inter-granular corrosion resistance, and the ability to efficiently achieve net and near-net configurations.
The forging process uses high pressure and temperature to change the non-directional, or one-directional grain structure of the aluminum starting material, into the high integrity multi-directional grain structure of forgings. The aluminum remains solid throughout the process as the forging dies come together and changes the shape of the starting stock.
The resulting directional orientation of the grain structure places the highest material strength in the same direction as the highest operating loads. The result is “premium strength”. The world’s leading aircraft and aerospace manufacturers use one-piece forgings for precisely this reason: superior performance in critical structural applications.
All of the forgings produced by Performance Forge have the additional benefit, when requested, of a polished mirror finish. This can be achieved because of the high integrity of the metallic structure produced by the forging process.
Other Frequently asked questions
Precision Forgings differ from Conventional Forgings in many ways. While Conventional forgings are typically machined on all surfaces, a Precision Forging is often characterized by very slight draft angles (0 to 1 degree), thin cross-sections, close tolerances, small radii, and excellent surface finishes.
While the tooling for a precision forging is typically more costly to produce and maintain, the advantages of precision forgings over conventional forgings pay multiple dividends. The net or near-net shape of the precision forging can greatly reduce machining times and produce a part that is nearly ready to put right into service. Additionally, the optimal grain structure of a precision forging increases fatigue life, and produces superior stress and inter-granular corrosion resistance.
- Forgings are stronger. A casting cannot obtain the strengthening effects that are produced in aluminum by hot working. The strength of a Forging surpasses that of a casting in all predictable strength properties.
- Forging refines grain structure. A casting has neither grain flow nor directional strength and the process cannot prevent formation of certain metallurgical defects. The hot working of forge stock produces a grain flow oriented in the directions that require maximum strength. Dendritic structures, alloy segregation’s and other casting imperfections are refined in forging.
- Forgings are more reliable, less costly. Because hot working refines grain pattern and imparts high strength, ductility and resistance properties, forged products perform more reliably and are more durable. As a result of their increased reliability and durability, their overall cost is often much less than a casting.
- Forgings have grain oriented to shape for greater strength. Machined bar and plate may be more susceptible to fatigue and stress corrosion because the machining process often cuts across the materials natural grain pattern. A well designed forging will yields a grain structure that is oriented to the part shape, resulting in optimum strength, ductility and resistance to impact and fatigue.
- Forgings yield lower scrap; greater, more cost-effective production. Forgings, especially near-net shapes, make better use of material and generate little scrap. In high-volume production runs, forgings have the decisive cost advantage.