Forging Terminology & Literature

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Literature

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Forging Takes Flight - Space Travel is Redefined

NASA's Curiosity Lands on Mars. Scot Forge Provides Traction

Scot Forge: NASA's Spaceflight Partner

Steel Bars Combine Forging and Rolling

Forging Raises the Bar on Magnesium Die Casting

Unusual Shaped Forging Breaks Ground - Literally

Raising the Roof in A Fault Zone

ABS Certified Forging Facility

New State of the Art 90MN Press for North American Forgemasters

Capabilities Brochure

Forging Solutions Brochure

Forge Industry Terms

Alloy Steel

Steel that, in addition to carbon, contains one or more elements in sufficient amounts to appreciably alter properties compared with those of carbon steel. Materials are alloyed to enhance physical and mechanical properties such as strength, ductility, and hardenability.

Annealing

A heat treating operation wherein metal is heated to a temperature above its critical range, held at that temperature long enough to allow full recrystallization, then slowly cooled through the critical range. Annealing removes working strains, reduces hardness, and increases ductility.

Austenitic Steels

Steels containing such proportion of an alloying element or elements that the austenitic structure is retained at room temperature.

Camel Back

A rectangular step-down bar that has the high point near the center.

Carbon Steel

Steel that owes its properties chiefly to various percentages of carbon with only residual amounts of alloying elements (except those added for composition control such as silicon and manganese).

Casting

Process of pouring molten metal into a prepared mold cavity of a desired shape and allowing the metal to solidify.

Centrifugal Casting

Casting process that consists of pouring molten metal into the cavity of a rotating mold, which can be made of various materials.

Charpy Impact Test

An impact test in which a specially V-notched specimen is broken by the impact of a falling pendulum. The energy absorbed in fracture is a measure of the impact strength or notch toughness of the sample.

Closed-Die Forging

Also called Impression Die Forging. A forging that is formed to the required shape and size by machined impressions in specially prepared dies that exert three-dimensional control on the workpiece.

Cogging

The reducing operation in working the ingots into a billet or bloom by the use of forging hammer or a forging press.

Concentric

Objects or part features having a common center.

Contour Torch Cutting

Torch cutting or flame cutting a part to achieve a specific shape or contour.

Billet

Also often called a bloom. A semifinished product of square, rectangular, or even round cross-section, hot rolled or forged. Producing billets or blooms from ingots by forging is called cogging, while by rolling it is called blooming.

Blank

A disc-type forging is produced by upsetting and rounding starting stock.

Boring

Machining a hole or enlarging an existing one with the objective of producing a more accurate hole than by drilling.

Bottom Poured Ingot

An ingot is produced by pouring molten steel into a vertical trumpet where the steel flows down the trumpet, through runners, and then enters the ingot mold from the bottom. This method provides substantially improved surface quality and internal soundness, as well as ingot yield advantages, over top-poured ingots.

Brinell Hardness

A measurement of a metal hardness (or ability to resist penetration). A steel ball is forced into the surface of the material tested under a specific load. The diameter of the depression is measured, and the hardness is the ratio of load to spherical area of the impression.

Fabrication

A part produced by any of a number of fabricating processes such as forming, rolling, punching or welding, but especially associated with weldments, the joining of two or more individual pieces by welding.

Fatigue Resistance

The ability of a metal to withstand repeated and varying loads without weakening.

Ferrous

Metals that contain iron as the major alloying element.

Flat Bar

A forged bar with a rectangular cross-section and the four corners are at right angles (90°).

Flat Head Spindle

A spindle with a rectangular head(s).

Forging

Process of working metal to the desired shape by impact or pressure from hammers, presses or forging machines. The metal object so produced is termed a forging.

Flanged (hollow)

A hollow forging with one or more protruding ribs or flanges on the outside diameter.

Hammer Forging

The mechanical forming of metal by means of a hammer. The action of the hammer is that of an instantaneous application of pressure in the form of a sudden blow.

Hardness

The ability of a metal to resist penetration, is defined in terms of the measurement (Brinell, Rockwell, etc.).

Hardness Test

A test used to determine the relative resistance to indentation or displacement of metals by pressure, or by resistance to abrasion. Common methods of testing include Brinell, Rockwell, and Vickers tests.

Head

Largest point of a forging.

Heat Treatment

An operation or combination of operations involving the heating and cooling of a metal or alloy in the solid state to attain certain desired microstructure or properties.

Hub

Part that has been upset forged using loose tools. This process produces a shape with a smaller diameter projection from either one or both sides of the major diameter of the part.

Hub

Part that has been upset forged using loose tools. This process produces a shape with a smaller diameter projection from either one or both sides of the major diameter of the part.

Machining

Process to remove excess or unwanted stock by the use of machine tools for rough or finish turning, boring, drilling, or milling.

Magnetic Particle Inspection

A nondestructive method of inspection for determining the existence and extent of possible defects in ferro-magnetic materials. Finely divided magnetic particles, applied to the magnetized part, are attracted to and outline the pattern of any magnetic leakage fields created by discontinuities.

Mandrel

A bar used to retain the cavity or enlarge the bore during hollow forging.

Manipulator

A mechanical device for handling an ingot or a billet during forging.

Mechanical Properties

Those properties of a material that reveal the elastic and inelastic reaction when force is applied, or that involve the relationship between stress and strain. Mechanical properties are dependent on chemical composition, forging, and heat treatment.

Metallographic Examination

Study of the microscopic features of material surfaces that have been specially prepared by cutting, grinding, polishing, and etching.

Metallurgical

Science of metals and alloys devoted to the study of engineering materials.

Microhardness Testing

Testing technique used for measuring the hardness of the constituents in the microstructure of a metal.

Milling

The process of producing machined surfaces by progressively removing a predetermined amount of material from the work piece which is fed to a rotating milling cutter.

Neck

Transition point when going from one size to another in a forging.

Necking

Refers to the operation of cutting a groove of predetermined depth in a work piece.

Nondestructive Testing

Any type of testing performed on an object that leaves it unchanged.

Non-ferrous

Metals that do not contain iron as the major alloying element.

Normalizing

Commonly used heat treatment that decreases pearlite interlamellar spacing and refines grain size. The process consists of heating steels above the transformation temperature range, holding at temperature, and then cooling in air.

Peeled Bar

A round bar that has been centerless machined to remove its outer surface. The peeling process takes less than one-fourth the time of conventional lathe-turning operations.

Planishing

A finishing operation used to obtain closer tolerances and a smoother surface on a round workpiece.

Planishing Mill, Bar

A custom-designed, computer controlled GFM single-stand bar mill. After an initial forging process, bars are sent through a series of reversing passes on the planishing mill where they are rolled to a smooth surface in less than five minutes.

Pneumatic Hammer

A forging hammer that uses compressed air both to drive the hammer down for a working blow to the workpiece and reposition it for the next blow.

Press Forging

Mechanical forming of metals by means of a press. The action is that of kneading the metal by relatively slow application of force as compared with the action of hammering.

Profiled Rolled Ring

A forged rolled ring with a contoured or profiled cross section achieved during the rolling process.

Ring Mill

Equipment used to produce forged rolled rings. A metal ring preform is rolled between two rolls that move toward each other to form a continuously reducing gap.

Ring Preform

Material that has been upset and pierced to form a hollow "donut." This is the starting stock needed to produce a rolled ring.

Rolled Ring

A forged seamless ring produced on a ring mill.

Rough Machining

A machining operation that allows stock for subsequent finish machining.

Saw Cutting

Metalworking process used to cut starting ingot or billet stock to length in preparation for the forging process and also to trim forged parts to size.

Scale

Oxidation that forms on the outside of hot metal and forms a crust. The appearance and amount of scale is depended on the grade of steel and the time it is in the furnace before processing.

Secondary Processing

As used in this reference, all metalworking processes that follow the forging process. Typical secondary processes are heat treating, rough machining, trimming, torch cutting, and testing.

Shot Blasting

A metal cleaning or finishing process in which a fluid blast blows abrasive steel balls against the surface.

Spectrochemical Analysis

Test performed to verify a material chemistry

Spindle

Also referred to as a stepdown shaft. A longitudinal bar-type product with more than one diameter or cross section size.

Square Bars

A forging that has four equal sides and the four corners are at right angles (90°).

Step-down Shaft

Also referred to as a spindle. A longitudinal bar-type product with more than one diameter or cross section size.

Stock

Stock is the amount of additional material above the rough turn print sizes. The more stock, the greater the chance the work piece will still be acceptable even with surface defects in present.

Tartan Bars®

Round bars 6" to 16" diameter with a forged center and rolled bar surface produced only by Scot Forge.

Thermocouple

A device consisting of two different conductors (usually metal alloys, termed “bi-metallic”) that produce a voltage proportional to a temperature difference, between either end of the two conductors. Thermocouples are a widely used type of temperature sensor for measurement and control.

Temper

Heat treat process performed after quenching or normalizing. The forging is heated to a temperature below the critical temperatures and cooled at a suitable rate. Tempering steel after hardening to relieve quenching stresses ensures dimensional stability and obtains specified mechanical properties.

Forging Terminology & Literature

Thank You For Your Interest In Forging

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Forge Industry Terms