The forging operation that locally reduces diameters in hollow forgings.

A term frequently used to mean variations in thickness of a forging.

The reducing operation in which an ingot is worked into a billet by the use of a forging hammer or a forging press.

(1) A post-forging process—on hot or cold parts—used to attain closer tolerances or improved surfaces. (2) A closed-die squeezing operation in which all surfaces of a workpiece are confined or restrained, resulting in a well-defined imprint of the die on the work.

Dies in which the coining or sizing operation is performed.

Various forging processes conducted at or near ambient temperatures to produce metal components to close tolerances and net shape. These include bending, cold drawing, cold heading, coining, extrusion (forward or backward), punching, thread rolling and others.

Plastically deforming metal at ambient temperatures to increase the cross-sectional area of the stock (either solid bar or tubing) at one or more points along the longitudinal axis. See also Heading and Upsetting.

A flaw that results when a workpiece fails to fill the die cavity during the first forging. A seam is formed as subsequent dies force metal over this gap to leave a seam on the workpiece surface. See also Cold Shut.

Mechanical sawing machine used to produce cut pieces prior to the forging operation. Sawing is carried out on the material at ambient temperature.

Also known as lap or fold. A defect such as lap that forms whenever metal folds over itself during forging. This can occur where vertical and horizontal surfaces intersect.

Removing flash or excess metal from the forging in a trimming press when the forging is at room temperature.

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.

A forging that has been restruck cold in order to hold closer face distance tolerances, sharpen corners or outlines, reduce section thickness, flatten some particular surface, or, in non-heat-treatable alloys, increase hardness.

A concave condition applicable to the width of any flat surface.

Adherence of part features to a common center.

Cooling from an elevated temperature in a predetermined manner to avoid hardening, cracking, or excessive internal stresses, or to produce a desired microstructure.

A forging characterized by design complexity and tolerances that fall within the broad range of general forging practice.

One made by equipment incorporating two opposed rams, which simultaneously strike repeated blows on the workpiece.

A category of forging equipment in which two opposed rams are activated simultaneously, striking repeated blows on the workpiece at a midway point. Action is vertical or horizontal.

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

The removal of carbon from the surface of steel as a result of heating in a medium that reacts with the carbon. Decarburization is usually present to a slight extent in steel forgings. Excessive decarburization can result in defective products.

Also known as bolster, insert holder, can. Used to locate, clamp and support dies, die assemblies or die inserts.

The portion of the die surface that shapes the forging.

A material sprayed, swabbed, or otherwise applied during forging to reduce friction and/or provide thermal insulation between the workpiece and the dies. Lubricants also facilitate release of the part from the dies and provide thermal insulation. See also Lubricant.

Also known as mismatch. The alignment of the upper (moving) and lower (stationary) impression in the die.