Compare Casting vs Forging

Compare and contrast casting to forging – in terms of part strength, prevention of defects, reliability of production, response to heat treatment, and adaption to production demand.

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Casting

Forging

Strength: Casting cannot obtain the strengthening effects of hot and cold working. Whether open or closed die forging is used, the forging process surpasses casting in predictable strength properties - producing superior strength that is assured, part to part.
Prevention of defects through pre-working: A casting has neither grain flow nor directional strength, and the casting process cannot prevent formation of certain metallurgical defects. Preworking forge stock produces a grain flow oriented in directions requiring maximum strength. Dendritic structures, alloy segregations and like imperfections are refined in forging.
 Reliability of Production: Casting defects occur in a variety of forms through the production process, requiring tight process controls and inspections to ensure a reliable final product. Because hot forging refines grain pattern and imparts high strength, ductility and resistance properties, forged products are both more reliable and free of the added costs for tighter process controls and inspection that are required for casting.
Response to heat treatment: Castings require close control of melting and cooling processes because alloy segregation may occur, which results in non-uniform heat-treatment response that can affect straightness of finished parts. Forgings respond more predictably to heat treatment and offer better dimensional stability.
Flexibility of production to demand: Some castings, such as special performance castings, require expensive materials and process controls, as well as longer lead times. Open die forging processes adapt to various production run lengths and enable shortened lead times.


For more information about forgings compared to castings, visit the Forging Industry Association (FIA) website.