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Closed die forging

Forging process in which a workpiece by means of one or more strokes is deformed between two closed mold halves.

Illustration of Closed die forging

The process

A heated workpiece is placed in a stationary mold half [1]. The upper mold half [2] is pushed against the workpiece with an applied pressure force and deformed and shaped by the two mold halves. It often requires several strokes before the mold cavity is fully filled.

To ensure that such a material is sufficient to fill the mold the workpiece volume is slightly larger than the mold. The design allows for excess material to flow outside the required shape and is trimmed away in a subsequent operation. In some cases, the part is repositioned in the mold to apply further strokes to achieve final size and volume.

The method allows for Precision forging where ingot size is carefully controlled.