Glossary

M-S

Machine forging (upsetter forging)

The process of forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. in a forging machineA type of forging equipment, related to the mechanical press, in which the main forming energy is applied horizontally to the workpiece, which is gripped and held by prior action of the grip dies. (upsetterA type of forging equipment, related to the mechanical press, in which the main forming energy is applied horizontally to the workpiece, which is gripped and held by prior action of the grip dies.), in which the metal is moved into the die impressionThe portion of the die surface that shapes the forging. by pressure applied in a horizontal direction by the moving dieThe machined recess in a die that gives the forging its shape. in the ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened..

Machining allowance

See Finish allowanceThe amount of stock left on the surface of the forging to be removed by subsequent machining. Also called "machining allowance" or "forging envelope.".

Macroetch

A testingA nondestructive method of inspection/testing for determining the existence and extent of possible defects in ferro-magnetic materials. The metal is magnetized, then iron powder is applied. The powder adheres to lines of flux leakage, revealing surface and near-surface discontinuities.... More procedure for conditions such as porosity, inclusionsParticles of nonmetallic compounds of metals and impurity elements that are present in ingots and are carried over in wrought products. The shape and distribution of inclusions are changed by plastic deformation and contribute to directionality in metals.... More, segregation, carburization, and flow linesPatterns in a forging resulting from the elongation of nonhomogeneous constituents and the grain structure of the material in the direction of working during forging; usually revealed by macroetching. See also Grain Flow. from hot workingThe plastic deformation of metal at such a temperature and strain rate that recrystallization takes place simultaneously with the deformation, thus avoiding any strain hardening. Also referred to as hot forging and hot forming. Contrast with cold working.... More. After applying a suitable etching solution to the polished metal surface, the structure revealed by the action of the reagent can be observed visually. See Etch testThe process of revealing the macrostructure of metals by preferential attack of a prepared surface by a suitable reagent..

Macrostructure

The structure and condition of metals as revealed on a suitably prepared and etched sample, and visible without the use of a microscope or under low magnification (up to 10 diameters).

Magnetic-particle inspection (testing)

A nondestructive method of inspection/testing for determining the existence and extent of possible defects in ferro-magnetic materials. The metal is magnetized, then iron powder is applied. The powder adheres to lines of flux leakage, revealing surface and near-surface discontinuitiesIncludes cracks, laps, folds, cold shuts, and flow-through, as well as internal defects such as inclusion, segregation, and porosity; internal discontinuities can be detected and evaluated using ultrasonic testing equipment..

Mandrel

A blunt-ended tool or rod used to retain or enlarge the cavityThe machined recess in a die that gives the forging its shape. in a hollow metal product during forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment..

Mandrel forging

The process of rolling and forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. a hollow blankRaw material or forging stock (also called a "slug" or "multiple") from which a forging is made. over a mandrelA blunt-ended tool or rod used to retain or enlarge the cavity in a hollow metal product during forging. in order to produce a weldless, seamless ring or tube. See Saddle/Mandrel Forging.

Manipulator

A mechanical device for handling an ingotA casting intended for subsequent rolling, forging, or extrusion. or a billetA semifinished, cogged, hot-rolled, or continuous-cast metal product of uniform section, usually rectangular with radiused corners. Billets are relatively larger than bars. See Bloom. during forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment..

Master

Wood, metal or plastic reproduction of a proposed forged shape, used to control cutters on tracer-controlled die sinkingThe process of machining impressions in die blocks. equipment.

Master block (or master holder)

A forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. dieThe machined recess in a die that gives the forging its shape. blockThe forging operation in which metal is progressively formed to general desired shape and contour by means of an impression die (used when only one block operation is scheduled). primarily used to hold insertA piece of steel that is tightly fixed in a die. The insert may be used to fill a cavity, to replace a portion of the die with a grade of steel that is better suited for service at that point, or to function as a small die with the impression fastened to a master die.... More diesThe metal blocks into which forging impressions are machined and from which forgings are produced..

Match

A condition in which a point in one dieThe machined recess in a die that gives the forging its shape. half is aligned properly with the corresponding point in the opposite dieThe machined recess in a die that gives the forging its shape. half within specified toleranceThe permissible deviation from a specification for any design characteristic..

Matching draft

Increased draftThe necessary taper on the side of a forging to allow removal from the dies; also applies to the die impression. Commonly expressed in degrees as the draft angle. As applied to open die forging, draft is the amount of relative movement of the dies toward each other through the metal in one application of power.... More used on the shallow side of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. to matchA condition in which a point in one die half is aligned properly with the corresponding point in the opposite die half within specified tolerance. its surface at the parting line(1) The line along the surface of a forging where the dies meet, usually at the largest cross section of the part. Flash is formed at the parting line. (2) The plane that divides the two forging die halves. with a similar surface of less draft on the deeper side.

Mechanical press

A forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine. with an inertia flywheel, a crank and clutch, or other mechanical device to operate the ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened..

Mechanical upsetter

A three-element forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine., with two gripper diesThe lateral or clamping dies used in a mechanical upsetter or forging machine. and a forming tool, for flanging or forming relatively deep recesses.

Metal discontinuities

See DiscontinuitiesIncludes cracks, laps, folds, cold shuts, and flow-through, as well as internal defects such as inclusion, segregation, and porosity; internal discontinuities can be detected and evaluated using ultrasonic testing equipment..

Microalloyed-steel forging

One made from a microalloyed steel requiring only controlled coolingCooling from an elevated temperature in a predetermined manner to avoid hardening, cracking, or excessive internal stresses, or to produce a desired microstructure. to reach optimum properties, in contrast to conventional quenched-and-tempered steels that require traditional heatAmount of forging stock placed in a batch-type furnace at one time. treatments to achieve the same results.

Microstructure

The structure and internal condition of metals as revealed on a ground and polished (and sometimes etched) surface when observed at high magnification (over 10 diameters).

Mill scale

The heavy oxide layer that forms during heating and forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. of steel.

Mismatch

The misalignment or error in register of a pair of forging diesForms for making forgings; they generally consist of a top and bottom die. The simplest will form a completed forging in a single impression; the most complex, consisting of several die inserts, may have a number of impressions for the progressive working of complicated shapes. Forging dies are usually in pairs, with part of the impression in one of the blocks and the rest of the impression in the other block.... More; also applied to the condition of the resulting forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment..

Mismatch allowance

An allowance for misalignment (or mismatchThe misalignment or error in register of a pair of forging dies; also applied to the condition of the resulting forging.) included in forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. tolerances.

Multiple

(1) Term used to describe a die impressionThe portion of the die surface that shapes the forging. designed to produce more than a single piece at a time. (2) A piece of stockThe material to be forged regardless of form. Also, an individual piece of metal used to produce a single forging. for forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. that is cut from barA section hot rolled from a billet to a form, such as round, hexagonal, octagonal, square, or rectangular, with sharp or rounded corners or edges, with a cross-sectional area of less than 16 sq in. (A solid section that is long in relation to its cross-sectional dimensions, having a completely symmetrical cross section and whose width or greatest distance between parallel faces is 3/8 in. or more).... More or billetA semifinished, cogged, hot-rolled, or continuous-cast metal product of uniform section, usually rectangular with radiused corners. Billets are relatively larger than bars. See Bloom. lengths to provide the exact amount of material needed for a single workpiece.

Natural draft

Taper on the sides of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment., due to its shape or position in the dieThe machined recess in a die that gives the forging its shape., that makes added draftThe necessary taper on the side of a forging to allow removal from the dies; also applies to the die impression. Commonly expressed in degrees as the draft angle. As applied to open die forging, draft is the amount of relative movement of the dies toward each other through the metal in one application of power.... More unnecessary.

Near-net-shape forging

ForgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. components as close as possible to the required dimensions of the finished part.

Nesting

The positioning of multiple(1) Term used to describe a die impression designed to produce more than a single piece at a time. (2) A piece of stock for forging that is cut from bar or billet lengths to provide the exact amount of material needed for a single workpiece. pieces in a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. dieThe machined recess in a die that gives the forging its shape. design.

Net-shape forging

(See also Precision forging(See also Net-shape forging) A forging produced to closer tolerances than normally considered standard by the industry.) ForgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. components on one or more sides to net shape requiring no further machining on at least one side. e.g. net forged gear with machined back face.

No-draft forging

A forged shape with extremely close tolerances and little or no draftThe necessary taper on the side of a forging to allow removal from the dies; also applies to the die impression. Commonly expressed in degrees as the draft angle. As applied to open die forging, draft is the amount of relative movement of the dies toward each other through the metal in one application of power.... More, requiring a minimum of machining to produce the final part. Mechanical properties can be enhanced by this closer control of grain flowFiber-like lines appearing on polished and etched sections of forgings that are caused by orientation of the constituents of the metal in the direction of working during forging. Grain flow produced by proper die design can improves the mechanical properties of forgings.... More and retention of surface material in the final component.

Nondestructive inspection

Any method of detection or measurement of the properties or performance capabilities of materials, parts, assemblies, or structures that does not impair the surface or internal integrity of the part.

Nonferrous

Metals or alloys that contain no appreciable quantity of iron; applied to such metals as aluminum, copper, magnesium, and their alloys.

Nonfill (underfill)

ForgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. condition that occurs when the finish(1) The forging operation in which the part is forged into its final shape in the finish die. If only one finish operation is scheduled to be performed in the finish die, this operation will be identified simply as finish; first, second, or third finish designations are so termed when one or more finish operations are to be performed in the same finish die. (2) The surface condition of a forging after machining. (3) The material machined off the surface of a forging to produce the finish machine component.... More die impressionThe portion of the die surface that shapes the forging. is not completely filled with metal. Some causes are: improper distribution of metal in preforming operations such as fulleringReducing the cross section of a forging between ends of stock., edgingThe forging operation of working a bar between contoured dies while turning it 90° between blows to produce a varying rectangular cross section., and blocking; excessive removal of material by chipping defects prior to finish forgingSee Conventional Forging.; improper lubrication of dieThe machined recess in a die that gives the forging its shape. impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging.; low forging pressure; rough or uneven dieThe machined recess in a die that gives the forging its shape. finish; inadequate hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. or press capacityThe rated force a press is designed to exert at a predetermined distance above the bottom of the stroke of the ram..

Nonmetallic inclusions

See InclusionsParticles of nonmetallic compounds of metals and impurity elements that are present in ingots and are carried over in wrought products. The shape and distribution of inclusions are changed by plastic deformation and contribute to directionality in metals.... More.

Offset

(1) A condition created in a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. when the diesThe metal blocks into which forging impressions are machined and from which forgings are produced. used in the forging operation do not align properly. (2) The alignment of the upper and lower diesThe metal blocks into which forging impressions are machined and from which forgings are produced. in the hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. or pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine..

Open die forging

ForgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. produced by working between flat or simply contoured diesThe metal blocks into which forging impressions are machined and from which forgings are produced. with unrestricted metal flow using repetitive strokes and continuous manipulation of the workpiece; sometimes called hand forging(See also Open Die Forging) (1) A forging made by hand on an anvil or under a power hammer without dies containing an exact finishing impression of the part. Such forgings approximate each other in size and shape but do not have the commercial exactness of production die forgings. Used where the quantity of forgings required does not warrant expenditure for special dies, or where the size or shape of the piece is such as to require means other than die forging. (2) A forging worked between flat or simply shaped dies by repeated strokes and manipulation of the piece. Also known as smith forging or flat die forging.... More.

Open dies

DiesThe metal blocks into which forging impressions are machined and from which forgings are produced. with flat surfaces that are used for preforming stockThe material to be forged regardless of form. Also, an individual piece of metal used to produce a single forging. or producing hand forgings.

Overetch

In the normal processing of aluminum forgings, a caustic etch operation is employed for the dual purpose of cleaningThe process of removing scale, oxides, or lubricant—acquired during heating for forging or heat treating—from the surface of the forging. (See also Blasting, Pickling, Tumbling.) parts and emphasizing defects to facilitate visual inspection. Immersion of parts for too long or use of too concentrated a solution will produce a rough, slightly pitted surface.

Overheated metal

Metal with an undesirable coarse grainAn individual crystal in a polycrystalline metal or alloy. structure due to exposure to an excessively high temperatureThe temperature of the forging stock just prior to forging.. Unlike a “burnt” structure, the metal is not permanently damaged but can be corrected by mechanical working.

Pancake forging

A rough forged shape, usually flat, that can be obtained quickly with minimal tooling. Considerable machining is usually required to attain the finish(1) The forging operation in which the part is forged into its final shape in the finish die. If only one finish operation is scheduled to be performed in the finish die, this operation will be identified simply as finish; first, second, or third finish designations are so termed when one or more finish operations are to be performed in the same finish die. (2) The surface condition of a forging after machining. (3) The material machined off the surface of a forging to produce the finish machine component.... More size.

Parting line

(1) The line along the surface of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. where the diesThe metal blocks into which forging impressions are machined and from which forgings are produced. meet, usually at the largest cross section of the part. FlashMetal in excess of that required to fill completely the blocking or finishing forging impression of a set of dies. Flash extends out from the body of the forging as a thin plate at the line where the dies meet and is subsequently removed by trimming. Because it cools faster than the body of the component during forging, flash can serve to restrict metal flow at the line where dies meet, thus ensuring complete filling of the impression. See also Closed-Die Forging.... More is formed at the parting line(1) The line along the surface of a forging where the dies meet, usually at the largest cross section of the part. Flash is formed at the parting line. (2) The plane that divides the two forging die halves.. (2) The plane that divides the two forging dieThe machined recess in a die that gives the forging its shape. halves.

Pick-up

Small particles of oxidized metal adhering to the surface of a mill product.

Pickling

The process of removing oxide scale from forgings by treating in a heated acid bath.

Pierce

In ring rolling, the process of providing a through hole in the center of an upset forging(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.... More using a tapered or cylindrical punch. See DriftingIn forging, the operation of forming or enlarging a hole by use of a tapered punch..

Plan view area

The area of the plan view of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment.; sometimes used to indicate the relative size of a forging.

Planishing

A finishing operation for the purpose of removing the trimThe removal of the excess metal or flash produced during the forging process. The operation takes place in tools produced to the peripheral shape of the component, the component being pushed through the female impression by the identically-shaped male punch. The operation may be carried out hot or at room temperature.... More line of forgings or of obtaining closer tolerances. Usually done by rolling, pressing or hammering, hot or coldFaults produced in a forging by incorrect tool design or incorrect flow of steel that results in the formation of a crack in the forging surface..

Plaster cast

See Lead ProofA reproduction in lead, or a lead alloy, of the die impression, obtained by clamping the two dies together in alignment and pouring molten metal into the finish impression..

Platter

The entire mass of metal upon which the hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. performs work, including the flashMetal in excess of that required to fill completely the blocking or finishing forging impression of a set of dies. Flash extends out from the body of the forging as a thin plate at the line where the dies meet and is subsequently removed by trimming. Because it cools faster than the body of the component during forging, flash can serve to restrict metal flow at the line where dies meet, thus ensuring complete filling of the impression. See also Closed-Die Forging.... More, sprueA portion of the die that has been removed by machining and permits the bar or tongs to be closer to the impression without being smashed., tonghold, and as many forgings as are made at one time.

Plug

(1) A protruding portion of a die impressionThe portion of the die surface that shapes the forging. for forming a corresponding recess in the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment.. (2) A false bottom in a dieThe machined recess in a die that gives the forging its shape..

Poisson’s ratio

The ratio of strain in the longitudinal direction to that in the transverse direction. Typical values range from 0.28 to 0.33 for most forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. alloys.

Powder forging

The plastic deformation of a powder metallurgy compact or preform(1) The forging operation in which stock is preformed or shaped to a predetermined size and contour prior to subsequent die forging operations. When a preform operation is required, it will precede a forging operation and will be performed in conjunction with the forging operation and in the same heat. (2) Ring blanks of a specific shape for profile (contour) ring rolling. (3) The initially pressed powder metallurgy compact to be subjected to repressing.... More into a fully dense finished shape by using compressive force; usually done hot and within closed diesThe metal blocks into which forging impressions are machined and from which forgings are produced..

Power rolls

Power-driven rolls used in preforming barA section hot rolled from a billet to a form, such as round, hexagonal, octagonal, square, or rectangular, with sharp or rounded corners or edges, with a cross-sectional area of less than 16 sq in. (A solid section that is long in relation to its cross-sectional dimensions, having a completely symmetrical cross section and whose width or greatest distance between parallel faces is 3/8 in. or more).... More or billetA semifinished, cogged, hot-rolled, or continuous-cast metal product of uniform section, usually rectangular with radiused corners. Billets are relatively larger than bars. See Bloom. stockThe material to be forged regardless of form. Also, an individual piece of metal used to produce a single forging. that have shaped contours and notches for introduction of the work.

Power-driven hammer

A forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. with a steam or air cylinder for raising the ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. and augmenting its downward blow.

Pre-pierce

(1) In ring rolling, a vertically mounted piercing (punching) tool used for preparation of ring blanks on the ring blankRaw material or forging stock (also called a "slug" or "multiple") from which a forging is made. pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine.. (2) A tapered tool of various diameters and lengths.

Precision forging

(See also Net-shape forging(See also Precision forging) Forging components on one or more sides to net shape requiring no further machining on at least one side. e.g. net forged gear with machined back face.) A forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. produced to closer tolerances than normally considered standard by the industry.

Preform

(1) The forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. operation in which stockThe material to be forged regardless of form. Also, an individual piece of metal used to produce a single forging. is preformed or shaped to a predetermined size and contour prior to subsequent dieThe machined recess in a die that gives the forging its shape. forging operations. When a preform(1) The forging operation in which stock is preformed or shaped to a predetermined size and contour prior to subsequent die forging operations. When a preform operation is required, it will precede a forging operation and will be performed in conjunction with the forging operation and in the same heat. (2) Ring blanks of a specific shape for profile (contour) ring rolling. (3) The initially pressed powder metallurgy compact to be subjected to repressing.... More operation is required, it will precede a forging operation and will be performed in conjunction with the forging operation and in the same heatAmount of forging stock placed in a batch-type furnace at one time.. (2) Ring blanks of a specific shape for profile (contour) ring rolling. (3) The initially pressed powder metallurgy compact to be subjected to repressing.

Preform impression

Any one or a combination of preliminary dieThe machined recess in a die that gives the forging its shape. impressions used in producing a preform(1) The forging operation in which stock is preformed or shaped to a predetermined size and contour prior to subsequent die forging operations. When a preform operation is required, it will precede a forging operation and will be performed in conjunction with the forging operation and in the same heat. (2) Ring blanks of a specific shape for profile (contour) ring rolling. (3) The initially pressed powder metallurgy compact to be subjected to repressing.... More. Also known as blocker, buster, scalebreak, and extrusionThe process of forcing metal to flow through a die orifice in the same direction in which energy is being applied (forward extrusion); or in the reverse direction (backward extrusion), in which case the metal usually follows the contour of the punch or moving forming tool. The extrusion principle is used in many impression die forging applications.... More.

Preheating

(1) A preliminary heating of ingots, billets, or forgings to reduce the hazards of thermal shock upon subsequent heating to higher temperatures. (2) A high-temperature soaking treatment used to change the metallurgical structure in preparation for a subsequent operation, usually applied to the ingotA casting intended for subsequent rolling, forging, or extrusion..

Preparation charge

A one-time charge covering the cost of sinkingThe operation of machining the impression of a desired forging into die blocks. diesThe metal blocks into which forging impressions are machined and from which forgings are produced. and preparing required auxiliary tooling for producing forgings to a particular design. In usual practice, this charge conveys to the customer the exclusive right to purchase forgings produced on this tooling. The diesThe metal blocks into which forging impressions are machined and from which forgings are produced. themselves are the property of the forger, who also has the responsibility for maintaining and replacing the dies as required for satisfactory production of forgings.

Press

A machine tool with a stationary bed and a slide or ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. that has reciprocating motion at right angles to the bed surface; the ram is guided in the frameThe main structure of a press. of the machine.

Press capacity

The rated force a pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine. is designed to exert at a predetermined distance above the bottom of the strokeThe vertical movement of a ram during half of the cycle, from the full open to the full closed position or vice versa. of the ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened..

Press forging

The shaping of metal between diesThe metal blocks into which forging impressions are machined and from which forgings are produced. on a mechanical or hydraulic pressA forging press with a hydraulically operated ram.. The action is that of kneading the metal by relatively slow application of force as compared with the action of hammering.

Pressure profile

A tabulation of the change in pressures across a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. section, usually in graphical form.

Profile (contour) rolling

In ring rolling a process to produce seamless rolled rings with a predesigned shape either on the outside or the inside diameter, requiring less volume of material and less machining to produce finished parts.

Progressives

A collection of sample forgings taken following the first and subsequent blows of the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. sequence. Also known as a progression.

Prolongation

An extra portion of metal added in a mutually agreeable location of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. to permit removal and subsequent testingA nondestructive method of inspection/testing for determining the existence and extent of possible defects in ferro-magnetic materials. The metal is magnetized, then iron powder is applied. The powder adheres to lines of flux leakage, revealing surface and near-surface discontinuities.... More without destroying the forging. Generally applies to open dieThe machined recess in a die that gives the forging its shape. and some large rolled rings.

Proof

Any reproduction of a die impressionThe portion of the die surface that shapes the forging. in any material. See also Lead ProofA reproduction in lead, or a lead alloy, of the die impression, obtained by clamping the two dies together in alignment and pouring molten metal into the finish impression..

Punchout

Metal removed when punching a hole in a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment..

Ram

The main reciprocating member of a pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine., guided in the press frameThe main structure of a press., to which the punch or upper dieThe machined recess in a die that gives the forging its shape. is fastened.

Ram adjustment

The distance that a pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine. ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. position can be altered to change the shut heightFor a press, the distance from the top of the bed to the bottom of the ram with the stroke down and adjustment up. In general, it is the maximum die height that can be accommodated for normal operation, taking the bolster plate into consideration. of the dieThe machined recess in a die that gives the forging its shape. space. The adjustment can be made by hand or by power mechanism.

Rib

A relatively flat (but generally with draftThe necessary taper on the side of a forging to allow removal from the dies; also applies to the die impression. Commonly expressed in degrees as the draft angle. As applied to open die forging, draft is the amount of relative movement of the dies toward each other through the metal in one application of power.... More) thin portion of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment., generally perpendicular to the forging planeThe plane that includes the principal die face and is perpendicular to the direction of ram travel. When parting surfaces of the dies are flat, the forging plane coincides with the parting line..

Sadden

To forge an ingotA casting intended for subsequent rolling, forging, or extrusion. lightly in the initial forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. operation in order to break up and refine coarse, as-cast structure at the surface.

Shoe

A holder used as a support for the stationary portions of forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. and trimming diesThe metal blocks into which forging impressions are machined and from which forgings are produced..

Shot blasting

A process of cleaningThe process of removing scale, oxides, or lubricant—acquired during heating for forging or heat treating—from the surface of the forging. (See also Blasting, Pickling, Tumbling.) forgings by propelling metal shot at high velocity by air pressure or centrifugal force at the surface of the forgings. See also Blast cleaningA process for cleaning or finishing metal objects by use of an air jet or centrifugal wheel that propels abrasive particles (grit, sand, or shot) against the surfaces of the workpiece at high velocity..

Shrink scale

A measuring scale or rule, used in dieThe machined recess in a die that gives the forging its shape. layout(1) Transferring drawing or sketch dimensions to templates or dies for use in sinking dies. (2) A detailed inspection operation in which significant dimensions of a forging are checked against blueprint specifications., on which graduations are expanded to compensate for thermal contraction (shrinkageThe contraction of metal during cooling after hot forging. Die impressions are made oversize according to precise shrinkage scales to allow the forgings to shrink to design dimensions and tolerances.) of the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. during cooling.

Shrinkage

The contraction of metal during cooling after hot forgingSame as hot working—plastically deforming an alloy at a temperature above its recrystallization point, i.e, high enough to avoid strain hardening.. DieThe machined recess in a die that gives the forging its shape. impressions are made oversize according to precise shrinkageThe contraction of metal during cooling after hot forging. Die impressions are made oversize according to precise shrinkage scales to allow the forgings to shrink to design dimensions and tolerances. scales to allow the forgings to shrink to design dimensions and tolerances.

Shut height

For a pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine., the distance from the top of the bed to the bottom of the ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. with the stroke downThe vertical movement of a ram during half of the cycle, from the full open to the full closed position or vice versa. and adjustment up. In general, it is the maximum dieThe machined recess in a die that gives the forging its shape. height that can be accommodated for normal operation, taking the bolster plateA plate to which dies can be fastened; the assembly is secured to the top surface of a press bed. In press forging, such a plate may also be attached to the ram. into consideration.

Shuts (cold)

Faults produced in a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. by incorrect tool design or incorrect flow of steel that results in the formation of a crack in the forging surface.

Side thrust

Lateral force exerted between the diesThe metal blocks into which forging impressions are machined and from which forgings are produced. by reaction of the forged piece on the dieThe machined recess in a die that gives the forging its shape. impressions.

Side thrust

Lateral force exerted between the diesThe metal blocks into which forging impressions are machined and from which forgings are produced. by reaction of the forged piece on the dieThe machined recess in a die that gives the forging its shape. impressions.

Sinking

The operation of machining the impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging. of a desired forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. into die blocksThe metal blocks into which forging impressions are machined and from which forgings are produced..

Sizing

Secondary forming or squeezing operations needed to square up, set down, flatten, or otherwise correct surfaces to produce specified dimensions and tolerances. Often accomplished with a coining(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.... More pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine.. See Coining.

Sliver

A slender fragment or splinter that is a part of the material, but that is incompletely attached. A torn fiberA characteristic of wrought metal, including forgings, indicated by a fibrous or woody structure of a polished and etched section, and indicating directional properties. Fiber is chiefly due to the extension of the constituents of the metal synonymous with flow lines and grain flow in the direction of working.... More of metal forced into the surface of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment..

Slot furnace

A common batch-type forge furnace where stockThe material to be forged regardless of form. Also, an individual piece of metal used to produce a single forging. is charged and removed through a slot or opening.

Slug

(1) Forging stockA wrought rod, bar, or other section suitable for subsequent change in cross section by forging. for one workpiece cut to length. See also BlankRaw material or forging stock (also called a "slug" or "multiple") from which a forging is made.. (2) Metal removed when punching a hole in a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. (also termed “punchout”).

Smith

The blacksmith, forger, or pressman.

Smith forging

See Flat die forgingForging worked between flat or simple contour dies by repeated strokes and manipulation of the workpiece. Also known as "hand" or "smith" forging. See Open-Die Forging., Hand forging(See also Open Die Forging) (1) A forging made by hand on an anvil or under a power hammer without dies containing an exact finishing impression of the part. Such forgings approximate each other in size and shape but do not have the commercial exactness of production die forgings. Used where the quantity of forgings required does not warrant expenditure for special dies, or where the size or shape of the piece is such as to require means other than die forging. (2) A forging worked between flat or simply shaped dies by repeated strokes and manipulation of the piece. Also known as smith forging or flat die forging.... More.

Smith hammer

Any power hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. where impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging. diesThe metal blocks into which forging impressions are machined and from which forgings are produced. are not used for the reproduction of commercially exact forgings.

Snag grinding (snagging)

The process of removing portions of forgings not desired in the finished product, by grinding.

Sow block

A blockThe forging operation in which metal is progressively formed to general desired shape and contour by means of an impression die (used when only one block operation is scheduled). of heat-treated steel placed between a hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. anvil and a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. dieThe machined recess in a die that gives the forging its shape. to prevent undue wear to the anvil. Sow blocks are occasionally used to hold insertA piece of steel that is tightly fixed in a die. The insert may be used to fill a cavity, to replace a portion of the die with a grade of steel that is better suited for service at that point, or to function as a small die with the impression fastened to a master die.... More diesThe metal blocks into which forging impressions are machined and from which forgings are produced.. Also called Anvil cap.

Split die

A dieThe machined recess in a die that gives the forging its shape. made of parts that can be separated for ready removal of the workpiece. Also known as segment dieThe machined recess in a die that gives the forging its shape..

Splitter impression

(1) A dieThe machined recess in a die that gives the forging its shape. cavityThe machined recess in a die that gives the forging its shape. used to divide laterally or split the material being worked so that it better covers the impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging. and reduces forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. load; (2) A dieThe machined recess in a die that gives the forging its shape. cavityThe machined recess in a die that gives the forging its shape. used to cut the material apart in the desired section by means of a shearing action.

Springback

(1) The elastic recovery of metal after stressing. (2) The extent to which metal tends to return to its original shape or contour after undergoing a forming operation. This is compensated for by overbending or by a secondary operation of restriking.

Stainless steels

Steels that are corrosion and heatAmount of forging stock placed in a batch-type furnace at one time. resistant and contain a minimum of 10% to 12% chromium. Other alloying elements are often present.

Stamp (marking)

An operation performed to identify the particular forgings as specified or requested by the customer.

Station

A regular stopping place in the dieThe machined recess in a die that gives the forging its shape. during the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. sequence.

Steam hammer

A type of drop hammerA term generally applied to forging hammers wherein energy for forging is provided by gravity, steam, or compressed air. See also Air-Lift Hammer, Board Hammer, Steam Hammer. where the ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. is raised for each strokeThe vertical movement of a ram during half of the cycle, from the full open to the full closed position or vice versa. by a double-action steam cylinder and the energy delivered to the workpiece is supplied by the velocity and weight of the ram and attached upper dieThe machined recess in a die that gives the forging its shape. driven downward by steam pressure. Energy delivered during each stroke may be varied.

Stock

The material to be forged regardless of form. Also, an individual piece of metal used to produce a single forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment..

Stock marks

In cutting forging stockA wrought rod, bar, or other section suitable for subsequent change in cross section by forging. to specified length for a die-forged part, the ends of the barA section hot rolled from a billet to a form, such as round, hexagonal, octagonal, square, or rectangular, with sharp or rounded corners or edges, with a cross-sectional area of less than 16 sq in. (A solid section that is long in relation to its cross-sectional dimensions, having a completely symmetrical cross section and whose width or greatest distance between parallel faces is 3/8 in. or more).... More always contain surface imperfections caused by the cutting tool; these are often retained on the surface of the finished part. If pronounced, such marks are removed by light grinding. On parts where repeated indications of stock marksIn cutting forging stock to specified length for a die-forged part, the ends of the bar always contain surface imperfections caused by the cutting tool; these are often retained on the surface of the finished part. If pronounced, such marks are removed by light grinding. On parts where repeated indications of stock marks are encountered, efforts are usually made to eliminate them by conditioning the stock ends prior to forging by polishing the cut ends and beveling the edge of the cut.... More are encountered, efforts are usually made to eliminate them by conditioning the stockThe material to be forged regardless of form. Also, an individual piece of metal used to produce a single forging. ends prior to forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. by polishing the cut ends and beveling the edge of the cut.

Straighten

Finishing operation for correcting misalignment in a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. or between different sections of a forging. Straightening may be done by hand, with simple tools, or in a dieThe machined recess in a die that gives the forging its shape. in forging equipment.

Straighten, coin

A combination coining(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.... More and straightening operation performed in special cavityThe machined recess in a die that gives the forging its shape. diesThe metal blocks into which forging impressions are machined and from which forgings are produced. designed to impart a specific amount of working in specified areas of the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. to relieve stresses set up during heat treatmentA sequence of controlled heating and cooling operations applied to a solid metal to impart desired properties..

Straighten, die

A straightening operation performed in either a hammerA machine that applies a sharp blow to the work area through the fall of a ram onto an anvil. The ram can be driven by gravity or power. See also Gravity Hammer and Power-Driven Hammer. or a pressA machine tool with a stationary bed and a slide or ram that has reciprocating motion at right angles to the bed surface; the ram is guided in the frame of the machine. using flat or cavityThe machined recess in a die that gives the forging its shape. diesThe metal blocks into which forging impressions are machined and from which forgings are produced. to remove undesired deformation and bring the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. within straightness toleranceThe permissible deviation from a specification for any design characteristic..

Straighten, hand

A straightening operation performed on a surface plate to bring a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. within straightness toleranceThe permissible deviation from a specification for any design characteristic.. Frequently, a bottom dieThe machined recess in a die that gives the forging its shape. from a set of finish(1) The forging operation in which the part is forged into its final shape in the finish die. If only one finish operation is scheduled to be performed in the finish die, this operation will be identified simply as finish; first, second, or third finish designations are so termed when one or more finish operations are to be performed in the same finish die. (2) The surface condition of a forging after machining. (3) The material machined off the surface of a forging to produce the finish machine component.... More diesThe metal blocks into which forging impressions are machined and from which forgings are produced. is used instead of a surface plate; hand tools used include mallets, sledges, blocks, jacks, and oil gear presses, in addition to regular inspection tools.

Strain hardening

An increase in hardness and strength caused by plastic deformation at temperatures below the recrystallization range. Also known as work hardening.

Stripper

A lug or ring on the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. or an impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging. in the diesThe metal blocks into which forging impressions are machined and from which forgings are produced. of a mechanical upsetterA three-element forging press, with two gripper dies and a forming tool, for flanging or forming relatively deep recesses. to ensure firm clamping of the workpiece in the gripper diesThe lateral or clamping dies used in a mechanical upsetter or forging machine..

Stripper punch

A punch that serves as the top or bottom of the dieThe machined recess in a die that gives the forging its shape. cavityThe machined recess in a die that gives the forging its shape. and later moves farther into the dieThe machined recess in a die that gives the forging its shape. to eject the part or compact. See also EjectorAlso known as knockout. Heat treated steel rods located within the dies and operated by the press action to remove a completed forging after the forging cycle. and KnockoutA mechanism for releasing workpieces from a die..

Stroke (up or down)

The vertical movement of a ramThe main reciprocating member of a press, guided in the press frame, to which the punch or upper die is fastened. during half of the cycle, from the full open to the full closed position or vice versa.

Structural integrity

Inherent microstructural soundness of forgings as a result of achieving 100% density, uniform metallurgical structure and grain sizeAn expression that rates the number of grains per unit area of cross section as determined by metallographic examination., as well as the absence of porosity, segregation, large inclusionsParticles of nonmetallic compounds of metals and impurity elements that are present in ingots and are carried over in wrought products. The shape and distribution of inclusions are changed by plastic deformation and contribute to directionality in metals.... More, and other non-forged part defects.

Sub-sow block (die holder)

A blockThe forging operation in which metal is progressively formed to general desired shape and contour by means of an impression die (used when only one block operation is scheduled). used as an adapter in order to permit the use of forging diesForms for making forgings; they generally consist of a top and bottom die. The simplest will form a completed forging in a single impression; the most complex, consisting of several die inserts, may have a number of impressions for the progressive working of complicated shapes. Forging dies are usually in pairs, with part of the impression in one of the blocks and the rest of the impression in the other block.... More that otherwise would not have sufficient height to be used in the particular unit or to permit the use of diesThe metal blocks into which forging impressions are machined and from which forgings are produced. in a unit where the shank sizes are different.

Suck-in

A defect caused by the “sucking in” of one face of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. to fill a projection on the opposite side.

Superalloys

A term broadly applied to iron-base, nickel-base, and cobalt-base alloys, often quite complex, that exhibit high elevated-temperature mechanical properties and oxidation resistance.

Superplasticity

The ability of certain metals to develop extremely high tensile elongations at elevated temperatures and under controlled rates of deformation.

Swaging

(1) Reducing the diameter of or rounding out a section of a forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. by a series of blows, tapering the forging lengthwise until the entire section attains the smaller dimension of the taper. (2) Tapering forging stockA wrought rod, bar, or other section suitable for subsequent change in cross section by forging. by forging, hammering, or squeezing.