6 DIFFERENT FORGING TECHNIQUES

Cold Work

Cold Working (FIA) — Permanent plastic deformation of a metal at a temperature below its
recrystallization point—low enough to produce strain hardening. Usually, but not necessarily, conducted
at room temperature. Also referred to as cold forming or cold forging. Contrast with hot working.
Cold Stamp (CDA): To restrike a forging cold in order to hold to closer tolerance, sharpen corners or
outlines, reduce section thickness, flatten some particular surface, increase hardness, or add lettering.

Cross-Grain Forge

Cross Forging (FIA) — Preliminary working of forging stock in alternate planes, usually on flat dies, to
develop mechanical properties, particularly in the center portions of heavy sections.

Hot Forge

Hot Forging (FIA) — Same as hot working—plastically deforming an alloy at a temperature above its
recrystallization point, i.e., high enough to avoid strain hardening.
Hot Press Forging (CDA): A method of forming parts by pressing a heated slug, cut from wrought
material, in a closed–impression die.

Upset & Cross-Grain Forge

This method of forging is a combination of Cross-Grain forging in that the work is done on alternate
plains, but also as in Upset Forging it is used to increase the cross-sectional area of a portion or all of the
stock.

Upset Forge

Upset Forging (FIA) — (1) A forging made by upsetting an appropriate length of bar, billet or bloom. (2)
Working metal to increase the cross-sectional area of a portion or all of the stock. (3) A forging formed by
heading or gathering the material by pressure upon hot or cold metal between dies operated in a
horizontal plane. This method is not used as frequently for copper alloys as it is for steels for example
due to the ability of copper to be easily extruded.

Warm Work

Warm Forging (FIA) — Deformation at elevated temperatures below the recrystallization temperature.
The flow stress and rate of strain hardening are reduced with increasing temperature; thus, lower forces
are required than in cold working. For steel, the temperatures range from about 1000° F to just below the
normal hot working range of 1900 to 2300° F. See also Cold Working and Hot Working.