open-die forging

Open-die forging is a metalworking process used in metallurgy to shape metal and enhance its strength by hammering or pressing. Unlike closed-die forging, it typically involves hammering a workpiece between flat dies. This method is often used for large parts that are impractical to form in a closed die, or when only a few items are needed, making the cost of a custom die uneconomical.123

The process can involve hydraulic presses exerting significant force, or air- and steam-driven hammers for greater control over the impact. The workpiece is manipulated and turned between blows to achieve the desired shape. For large ingots, heating can take many hours, and reheating may be necessary multiple times during the forging operation. This technique is crucial for producing large components like power-generating rotors or sleeves for pressure vessels.32