Forging Terms and Definitions

Backward Extrusion

 

 Backward extrusion, another cold forging process, produces hollow parts. Here, the metal flows back around the descending ram in the opposite direction. 

 

Forward Extrusion

 

 Forward extrusion, a basic cold forging operation, reduces slug diameter while increasing length. Stepped shafts and cylinders are typical examples of this process

 

Forging Terms and Definitions

From Rough Machining to Wide tolerance
Courtesy of Forging Industry Association

Rough machining: an initial machining operation that leaves adequate stock for subsequent finish machining.

Saddle/mandrel forging: rolling and forging a pierced disc over a mandrel to yield a seamless ring or tube.

Slab: a flat-shaped semifinished, rolled metal ingot with a width not less than 10 in. and a cross-sectional area not less than 16 sq. in.

Standard tolerance: an established tolerance for a certain class of product; preferred over "commercial" or "published" tolerance.

Straightening: a finishing operation for correcting misalignment in a forging or between different sections of a forging.

Structural integrity: inherent microstructural soundness of forgings as a result of achieving 100% density, uniform metallurgical structure and grain size, as well as the absence of porosity, segregation, large inclusions and other non-forged part defects.

Swaging: reducing the size of forging stock; alternately, forging in semicontoured dies to lengthen a blank.

Target machining: incorporating a "target" (benchmark or gage point) on a forging to facilitate machining; coined locating surfaces and drilled centers are commonly used..

Cold-coined forging: the specified permissible deviation from a specified or nominal dimension; the permissible variation in the size of a part.

Trimming: performed hot or cold, the mechanical shearing of flash or excess material from a forging by use of a trimmer in a trim press.

Upset forging: one made by upset of an appropriate length of bar, billet or bloom; working metal to increase the cross-sectional area of a portion or all of the stock.

Upsetter (forging machine): a machine with horizontal action used to produce upset forgings.

Warm forging: forging of steel at temperatures ranging from about 1000 degrees F to just below the normal hot working range of 1900 to 2300 degrees F.

Web: a relatively flat, thin portion of a forging - generally parallel to the forging plane - that connects ribs and bosses.

Wide tolerance: any special tolerance wider than "standard"..

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