Glossary of tube terms used in the industry

A

ACID BRITTLENESS
The brittleness induced in steel, especially wire or sheet, when it is pickled in dilute acid to remove scale, or during electroplating. Commonly attributed to absorption of hydrogen.
ACID STEEL
Steel made in a furnace or converter lined with siliceous (acid) refractory material. In the open hearth and electric furnaces employing the acid process, the hearth or bottom consists of fritted ("burned in") silica sand. The acid bessemer converter usually is lined with a kind of sandstone called "firestone." Raw materials for acid steel Must be low in phosphorus and sulfur.
ADDITIONS
Materials which are added to the molten bath of steel or to the molten steel in the ladle to produce the chemical composition required for the specific steel order.
AGE HARDENING
A process of aging that increases hardness and strength and ordinarily decreases ductility. Age hardening usually follows rapid cooling or cold working.
AGING
The process by which steel changes in mechanical properties on long standing at ordinary room temperatures. Aging may change impact value, tensile strength, yield point, and behavior in certain forming operations.
AIRCRAFT QUALITY
Denotes material for important or highly stressed palls. of aircraft and for other similar purposes; such materials are of extremely high quality requiring closely controlled, restrictive and special practices in their manufacture.
ALLOY
A substance that has metallic properties and is composed of two or more chemical elements of which at least one is a metal.
ALLOY SCRAP
Scrap steel which contains one or more alloying metals, such as nickel, chromium, tungsten, molybdenum. Such scrap must be very carefully classified according to ' composition and kept separate from other kinds of scrap.
ALLOY STEEL
"Steel is classified as alloy when the maximum of the range given for the content of alloying elements exceeds one or more of the following: manganese, 1.65 pet; silicon, 0.60 pet; copper, 0.60 pct; or in which a definite range or a definite minimum quantity of any of the following elements is specified or required within the limits of the recognized field of constructional alloy steels: aluminum, boron, chromium up to 3.99 pet, cobalt, columbium, molybdenum, nickel, titanium, tungsten, vanadium, zirconium, or any other alloying element added to obtain a desired alloying effect."
ALLOYING ELEMENTS
Chemical elements added for improving the properties of the finished products. Chief alloying elements in medium alloy steels are: nickel, chromium, manganese, molybdenum, vanadium, silicon, copper.
ALPHA IRON
The form of iron that is stable below Ac3 (1670°F., e.g., the temperature at which a change in phase occurs). See also Austenite, Ferrite and Gamma Iron.
ANNEAL, DEOXIDIZING
A sub-critical anneal performed in an inert atmosphere in order to minimize oxidation, remove internal strains after cold reduction, decrease hardness and tensile strength and develop maximum ductility.
ANNEALING
A process involving heating and cooling, usually applied to induce softening. The term also refers to treatments intended to alter mechanical or physical properties, produce a definite microstructure, or remove gases.
ANNEALING (BRIGHT)
A process of annealing usually carried out in a controlled furnace atmosphere so that surface oxidation is reduced to a minimum and the surface remains relatively bright.
ANNEALING (FULL ANNEALING)
A softening process in which a ferrous alloy is heated to a temperature above the transformation range and after being held for a sufficient time at this temperature, is cooled slowly to a temperature below the transformation range. The alloy is ordinarily allowed to cool slowly in the furnace, although it may be removed and cooled in some medium that ensures a slow rate of cooling.
ANNEALING (GRAPHITIZING)
A heating and cooling process by which the combined carbon in cast iron or steel is transformed, wholly or partly, to graphitic or free carbon.
ANNEALING (MALLEABLIZING)
A process of annealing white cast iron in such a way that the combined carbon is wholly or partly transformed to graphitic or free carbon or, in some instances, part of the carbon is removed completely.
ANNEALING (NORMALIZING)
A process in which a ferrous alloy is heated to a suitable temperature above the transformation range and is subsequently cooled in still air at room temperature.
ANNEALING (PATENTING)
Heating iron-base alloys above the critical temperature range followed by cooling to below that range in air or in molten lead maintained at a temperature of about 700°P.
ANNEALING (PROCESS ANNEALING)
In the sheet and wire industries, a process by which a ferrous alloy is heated to a temperature close to, but below, the lower limit of the transformation range and is subsequently cooled. This process is applied in order to soften the alloy for further cold working.
ANNEALING (SPHEROIDIZING)
Any process of heating and cooling that produces a rounded or globular form of carbide in steel. Spheroidizing methods frequently used are:

            1. Prolonged holding at a temperature just below Ae1.

            2. Heating and cooling alternately between temperatures that are just above and j-List below Ae1.

            3. Heating to a temperature above Ae1 or Ae3 and then cooling very slowly in the furnace, or holding at a temperature just below Ae1.

            4. Cooling at a suitable rate from the minimum temperature at which all carbide is dissolved, to prevent the re-formation of a carbide network, and then reheating in accordance with method 1 or 2 above (applicable to hypereutectoid steel containing a carbide network).
ANNEALING (TEMPERING)
A process of reheating quench-hardened or normalized steel to a temperature below the transformation range, and then cooling at any rate desired.
AUSTENITE
A solid solution formed when carbon and certain alloying elements dissolve in gamma iron. Gamma iron is formed when carbon or constructional alloy steel is heated above the so-called critical range, and the ferrite (alpha iron, with a body-centered crystal structure) is transformed to a face-centered crystal structure. Austenite does not exit in most ordinary steels at room temperature.
AUSTENITIC GRAIN SIZE
As used in this publication, is the grain structure established by a standardized heat treatment procedure.
AUSTENITIC STEEL
A steel in which the iron is in the gamma form at room temperature and which does not undergo thermal transformations in heating or cooling.
AUSTENITIZING
The process of forming austenite by heating a ferrous alloy to temperatures in the transformation range (partial austenitizing) or above the transformation range (complete austenitizing).

B

BALLISTIC TEST
A test in which a projectile is fired at an armor plate. The armor plate or the projectile (whichever one is being tested) must meet certain requirements.
BANDED STRUCTURE
A segregated structure of nearly parallel bands aligned in the direction of working.
BASIC BOTTOM AND LINING
In a melting furnace, the inner lining and bottom composed of either crushed burned dolomite, magnesite, magnesite bricks or basic slag. These materials have a basic reaction in the melting process.
BASIC MATERIAL
A chemical expression meaning the opposite of acid. Basic and acid materials, when brought together so that they can react, neutralize each other, forming salts or slags. In such reactions, the base becomes the positive part of the salt and the acid the negative. Examples of basic materials; limestone (or lime, CaO), magnesite (MgO), dolomite (containing both CaO and MgO). Examples of acid materials; quartzite or silica (SiO2) and the various clays, oxides of sulfur, etc. In metallurgy, the terms, "bases" and "acids," are applied to refractories, fluxes, and slags. Slags are said to be basic when the bases in them are greater than the acids; or to be acid when the acids in them are greater than the bases.
BASIC STEEL
Steel melted in a furnace that has a basic bottom and lining, and under a slag that is dominantly basic.
BEADING
Raising or depressing a ridge, of specified contour, on a section of tubing.
BEAM
An important member of the structural steel family. There are three varieties —the standard H, I, and wide flange used for the weight supporting purposes.
BEND RADIUS
The radius corresponding to the curvature of a bent specimen or bent area of a formed part, and measured on the inside of a bend.
BEND TESTS
Tests used to determine the ductility and/or other characteristics of tubing. The number of bends and the radius and degree of bends are generally determined by f the applicable specifications.
BENDING ROLLS
Three staggered rolls adjusted to put the desired curvature in plate or used for coiling and uncoiling strip or wire.
BESSEMER PROCESS
A process for making steel by blowing air under pressure through molten pig iron contained in suitable vessel, whereby a portion of the iron, most of the silicon and manganese and practically all the carbon are eliminated by oxidation. See Converter.
BLOWHOLE
An internal cavity in steel produced during the solidification of the metal by evolved gas which, in failing to escape, is held in pockets.
BLUE BRITTLENESS
Brittleness occurring in plain carbon steel when heated in the temperature range of 400° to 650° F., or when cold after being worked within this temperature range.
BLUE PLATE
Black plate the surface of which has been oxidized at a suitable temperature with steam or air to produce a blue color.
BOX ANNEALING
A process of annealing a ferrous alloy in a suitable closed metal container with or without packing material in order to minimize oxidation. The charge is usually heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly. This process is also called "close annealing" or "pot annealing."
BRAZING
Joining metals by fusion of nonferrous alloys that have melting points above 800°F. but lower than those of the metals being joined. This may be accomplished by means of a torch (torch brazing), in a furnace (furnace brazing) or by dipping in a molten flux bath (dip or flux brazing). The filler metal is ordinarily in rod form in torch brazing; whereas in furnace and dip brazing the work material is first assembled and the filler metal may then be applied as wire, washers, clips, bands, or may be integrally bonded, as in brazing sheet.
BRAZING SHEET
A clad type of sheet product, coated on one or both surfaces with an alloy that has a melting point lower than the melting point of the core alloy. During brazing, only the coating melts and flows to form fillets in the preassembled article.
BRIGHT DIP
An acid solution into which articles are dipped to obtain a clean, bright surface.
BRITTLENESS
A tendency to fracture without appreciable deformation.
BULGING
Local expansion of tubes or shells by internal hydraulic pressure or by compression of a rubber cylinder.
BURNISHING
Plastic smearing such as may occur on metallic surfaces during buffing.
BURR
A rough or sharp edge left on metal by a cutting tool.
BUTT WELDING
Joining two edges or ends by placing one against the other and welding them.

C

CAMBER
A bend in a plate or other product of a rolling mill which results because one edge or side is longer than the other. Camber in plates is often caused by rolls which are closer together at one end than at the other, or by uneven temperatures in the slab. In rails and structural shapes, the camber is the "up or down" curvature, as distinguished from the sidewise curvature or "sweep."
CAMBER OF ROLLS
The increased diameter at the middle of rolls, designed to counter-balance the bending of the rolls when they are subjected to high pressures during rolling.
CAMBER OF SHEET
Curvature in the plane of rolled sheet or strip.
CAPPED STEEL
Capped steel, a variation of rimmed steel, is cast in a bottle top mold. The cap, placed in the neck of the mold soon after the mold has been filled to the proper level, stops the rimming action before it is completed by cooling the top metal. The product is an ingot having a thin rim relatively free of blowholes and with less segregation than is usual for a rimmed ingot of the same volume.
CARBIDE
A compound of carbon with one or more metallic elements.
CARBON STEEL
Steel which owes its properties chiefly to various percentages of carbon without substantial amounts of other alloying elements; also known as straight carbon steel, or plain carbon steel. Steel is classified as carbon steel when no minimum content of elements other than carbon is specified or required to obtain a desired alloying effect; when the specified minimum for copper does not exceed 0.40 pet; or the maximum content for the following does not exceed the percentages noted: manganese, 1.65; silicon, 0.60; copper, 0.60.
CARBONITRIDING
A process in which a ferrous alloy is case-hardened by first being heated in a gaseous atmosphere of such composition that the alloy absorbs carbon and nitrogen simultaneously, and then being cooled at a rate that will produce desired properties.
CARBURIZING
To introduce carbon: (1) while steel is molten by adding carbonaceous material, coke, coal, electrode scrap, etc.; (2) while steel is in the solid state by heating it in contact with carbonaceous matter below its melting point.
CASE-HARDENING
A process of hardening a ferrous alloy so that the surface layer or case is made substantially harder than the interior or core. Typical case-hardening processes are carburizing and quenching, cyaniding, carbonitriding, nitriding, induction hardening and flame hardening.
CHAMFER
To cut at an angle or bevel.
CHIPPING
A method for removing seams and other surface defects with chisel or gouge so that such defects will not be worked into the finished product. Chipping is often employed also to remove metal that is excessive but not defective. Removal of defects by gas cutting is known as ”deseaming" or "scarfing."
CHROME PICKLE
A chemical treatment for magnesium in a nitric acid, sodium dichromate solution. The treatment gives some protection against corrosion by producing a film that is also a base for paint.
CHROME-CARBIDE PRECIPITATION
A chemical reaction sometimes occurring in chrome-nickel steel, in which the chromium, near the boundaries of the grains, flows to the boundaries and unites with carbon, thus forming the chrome carbides and depleting the chromium supply in the metal near the grain boundaries. This makes the steel susceptible to intergranular corrosion when brought into contact with various acids or alkalis.
CHROMIUM
An alloying element added to alloy steel (in amounts up to around 1.50 pet) to increase hardenability. Chromium content of 5 pct or more confers special ability to resist corrosion. Steels containing more than 10.5 pet chromium are called "Stainless Steel."
CIRCULAR WELD
Safe end weld. A weld extending around a girth seam. Such welds are sometimes butted, but frequently are scarfed.
CLADDING
A process for covering one metal with another. In tubing this is accomplished by placing one tube within a thin-walled cladding tube and drawing down the cladding tube until it is firmly fastened to the inner tube.
COATING
The process of covering steel with another material, primarily for corrosion resistance.
COHESIVE STRENGTH
A term used with one of the following meanings:
1. The maximum stress required in order to cause tensile fracture in the absence of any deformation, when two of the three principal stresses equal zero; that is, with a notched bar. Sometimes called "initial cohesive strength."
2. The maximum principal stress required in order to cause tensile fracture when triaxial stresses are present; that is, by using a notched test bar. This is frequently called the "technical cohesive strength" and is variable, depending on the relative magnitude of the three principal stresses, the amount of plastic deformation preceding fracture, and the temperature and rate of straining.
COLD DRAWN
Refers to tubing drawn in the cold state through a hardened steel or carboloy die, either with or without a mandrel on the inside.
COLD HEADING
Cold heading consists in forcing metal to flow cold into dies to form thicker sections and more or less intricate shapes. The operation is performed to specialized machines where the metal, in the form of wire or bar stock, may be upset or headed in certain sections to a larger size and, if desired, may be extruded in other sections to a smaller diameter than the stock wire. Although cold heading was developed for the production of bolts, screws, and rivets and is used largely for these parts, the process is applicable to a wide variety of special parts that have somewhat similar form.
COLD HEADING QUALITY
Produced by closely controlled steelmaking practices including special melting, rolling, conditioning, inspection and testing, in order to be defect free and satisfactory for cold heading.
COLD ROLLED PRODUCTS
Flat-rolled products which have been finished by rolling the piece without heating (at approximately room temperature).
COLD SHUT
1. A discontinuity that appears on the surface of cast metal as a result of two streams of liquid meeting and failing to unite. Pouring the metal when it is too cold may cause such a discontinuity.
2. On a forging, a portion of the surface that is separated by oxide from the main body of metal.
COLD WORK
Plastic deformation at such temperatures and rates that substantial increases occur in the strength and hardness of the metal. Visible structural changes include changes in grain shape and, in some instances, mechanical twinning or banding.
COLD WORKING
Deforming a metal plastically at such a temperature and rate that strain hardening occurs. The upper limit of temperature for this process is the recrystallization temperature.
COLLAPSING PRESSURE
A pressure, which, when applied to the outside of a tube, causes it to cave in, or to fail by bending or buckling inwardly.
COLUMBIUM
A metal which may be added to chrome-nickel stainless steel to improve its welding qualities, by preventing carbide precipitation.
COMBINED CARBON
The carbon that is combined with iron or alloying elements to form carbide in cast iron or steel.
COMPRESSIVE TEST (TUBING)
Test made on a section of tube applying compressive force perpendicular to the axis of the tube.
CONCENTRICITY
AS reference to a tube, the center line of inside diameter is consistent with the center line of the outside diameter.
CONDUIT PIPE
Wrought pipe used as armor for electric wires.
CONSTANT-LOAD TEST
A stress-corrosion cracking or mechanical test in which the specimen is stressed by applying a dead load.
CONTROLLED COOLING
A process of cooling from an elevated temperature in a pre-determined manner, to avoid hardening, cracking or internal damage, or to produce a desired microstructure. This cooling usually follows the final hot forming operation.
COOLING STRESSES
Stresses developed by uneven contraction of external constraint of metal during cooling; also those stresses resulting from localized plastic deformation during cooling, and retained.
CORE
In a ferrous alloy, the interior portion that is substantially softer than the surface layer or case, after case hardening.
CORE
1. A body of sand or other material placed in a mold to produce a cavity of desired shape in a casting.
2. A tubular defect that comes from the surface of a billet and appears at the back end of extruded rod.
3. The center or base portion of a clad product.
CORE LOSS
That part of the electrical energy required to magnetize a core of magnetic material that is dissipated as heat generated within the core, as distinguished from the energy lost in the coil surrounding the core.
CORROSION
Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents.
CORROSION EMBRITTLEMENT
The embrittlement caused in certain alloys by exposure to a corrosive environment. Such material is usually susceptible to the intergranular type of corrosion attack.
CORROSION FATIGUE
The repeated cyclic stressing of a metal in a corrosive medium, resulting in more rapid deterioration of properties than would be encountered as a result of either cyclic stressing or of corrosion alone.
COUPLE
Two dissimilar conductors in electrical contact. An electromotive force is created under proper electrolytic influences or during heating.
COUPLING
A threaded sleeve used to connect two pipes. Commercial couplings are threaded inside to suit exterior thread of pipe.
CREEP
The flow or plastic deformation of metals held for long periods of time at stresses lower than the normal yield strength. The effect is particularly important if the temperature of stressing is in the vicinity of the recrystallization temperature of the metal.
CREEP LIMIT
The maximum stress that will result in creep at a rate lower than an assigned rate.
CREEP STRENGTH
All stressed metals slowly deform at elevated temperatures even under stresses below their short-time yield points. This deformation is called "creep." The creep strength is determined by loading specimens maintained at high temperatures for 1000 hours or more, noting the deformation, and then calculating the stress in polands per square inch required to produce one per cent elongation in 10,000 or in 100,000 hours.
CRITICAL STRAIN
The percentage strain at which, or immediately higher than which, large grain growth occurs during heating.
CROP
The end or ends of an ingot that contain the pipe or other defects to be cut off and discarded; also termed "crop end" and "discard."
CRUCIBLE
A ceramic pot or receptacle made of graphite and clay, or clay or other refractory material, used in the melting of metal.
CRUSHED TEST
Same as Compression Test.
CRYSTALLIZATION
The formation of crystals by the atoms assuming definite positions in a crystal lattice. This is what happens when a liquid metal solidifies. (Fatigue, the failure of metals under repeated stresses, is sometimes falsely attributed to crystallization.)
CUP FRACTURE
The type of fracture in which the exterior portion is extended and the interior is relatively depressed, resembling a cup. When only a part of the exterior is extended, the term "half-cupped" or "quarter-cupped" is used.
CYANIDING
A process of case hardening a ferrous alloy by heating in a molten cyanide, thus causing the alloy to absorb carbon and nitrogen simultaneously. Cyaniding is usually followed by quenching to produce a hard case.

D

DECAREURIZATION
The loss of carbon from the surface of a ferrous alloy as a result /Of heating in a medium that reacts with the carbon.
DEEP DRAWING
Forming shaped articles or shells by forcing sheet metal into a die.
DEEP ETCHING
Macro-etching; etching, for examination at a low magnification in a reagent that attacks the metal to a much greater extent than normal for microscopic examination. Gross features may be developed: Abnormal grain size segregation, cracks or grain flow.
DESCALING
The process of removing scale from the surface of steel. Scale forms most readily when the steel is hot by union of oxygen with iron. Common methods of descaling are:

1. Crack the scale by use of roughened rolls and remove by a forceful water spray,

Throw salt or wet sand or wet burlap on the steel just previous to its passage through the rolls.
DIFFERENTIAL HEATING
A heating process by which the temperature is varied within the object so that, after cooling, various parts may have different properties as desired.
DIFFUSION ZONE
In the clad type of products, the zone between coating and core, in which diffusion between the two has occurred.
DIMENSIONS
O.D. : — Outside Diameter. Specified in inches and fractions of an inch, or in inches and decimals of an inch.

I.D.: — Inside Diameter. Specified in same terms as the O.D.

WALL: —Wall thickness or Gage. Specified in either fractions of an inch, decimals of an inch or by a "Wire Gage" number. In the United States the standard wire gage used for tubing is the "Birmingham" iron wire gage, designated "B.W.G."
DIRECT QUENCHING
A process of quenching carburized parts directly from the carburizing operation.
DRAWING QUALITY
Flat-rolled products produced from either deep drawing rimmed steel or extra deep drawing aluminum killed steels. Special rolling and processing operations aid in producing a product which can stand extreme pressing, drawing, or forming, etc., without creating defects.
DRY CYANIDING
Synonymous with carbonitriding.
DUCTILITY
The property that permits permanent deformation before fracture by stress in tension.

E

ELASTIC AFTEREFFECT
A slight contraction that occurs slowly while metal is standing with no load, subsequent to plastic tensile flow and immediate elastic recovery. Microscopic stresses, acting in compression, are responsible for this as well as for the Bauschinger effect.
ELASTIC CONSTANTS
In the general form of Hookes Law, the elastic moduli, which vary in individual crystals with the direction of test. ELASTIC DEFORMATION—Temporary changes caused in dimensions by stress. The material returns to the original dimensions after removal of the stress.
ELASTIC HYSTERESIS
Energy absorbed by reversed deformation, represented by the closed loop of stress-strain curves in the elastic range, formed by curves for loading and unloading.
ELASTIC LIMIT
The maximum stress which a material is capable of sustaining without any measurable permanent extension remaining after complete release of the applied force.
ELECTROCHEMICAL CORROSION
Localized corrosion that results from exposure of an assembly of dissimilar metals in contact or coupled with one another; or of a metal containing macroscopic or microscopic areas dissimilar in composition or structure. The dissimilar elements form short-circuited electrodes, the corrosive medium is the electrolyte, and an electric current is induced, which results in the dissolution of the electrode that has the more anodic solution potential, while the other is unattacked. The same condition may result from local differences within the corroding medium.
ELONGATION
The amount of permanent extension in the vicinity of the fracture in the tension test; usually expressed as a percentage of the original gage length, as 25% in 2 in. Elongation may also refer to the amount of extension at any stage in any process that elongates a body continuously, as in rolling.
ENDURANCE LIMIT
The maximum Stress that a metal will withstand without failure during a specified large number of cycles of stress. If the term is employed without qualification, the cycles of stress are usually such as to produce complete reversal of flexural stress.
ENDURANCE RATIO
The ratio of the endurance limit for cycles of reversed flexural stress to the tensile strength.
EROSION
The abrasion of metal or other material by liquid or gas, usually accelerated by pressure of solid particles of matter in suspension, and sometimes by corrosion
ETCH TESTS
Tests used to detect inclusions in steel. A common method of making the test is to dip the sample into acid which reacts with the inclusions and discloses their presence.
ETCHING
In metallography, the process of revealing structural details by the preferential attack of reagents on a metal surface.
EXFOLIATION
A type of corrosion that progresses parallel to the outer surface of the metal, causing layers of the metal to be elevated by the formation of corrosion product.
EXPLOSIVE RIVET
A type of blind fastener in which a hollow-shank rivet is used, containing an explosive charge. The rivet shank is expanded by exploding the charge after the rivet has been inserted.
EXTRUSION
Shaping metal into a chosen continuous form by forcing it through a die of appropriate shape.

F

FABRICATOR, STEEL
One who forms, manufactures or builds. His operations are to punch, cut, shear, drill, bend, flange or weld plates and shapes.
FATIGUE
The tendency for a metal to break under conditions of repeated cyclic stressing considerably below the ultimate tensile strength.
FATIGUE CRACK OR FAILURE
A fracture starting from a nucleus where there is an abnormal concentration of cyclic stress and propagating through the metal. The surface is smooth and frequently shows concentric (sea shell) markings with a nucleus as a center.
FATIGUE LIMIT
The maximum stress that a metal will withstand without failure for a specified large number of cycles of stress. Usually synonymous with endurance limit.
FERRITE
A solid solution in which alpha iron is the solvent, and which is characterized by a body-centered cubic crystal structure.
See also Austenite, Alpha Iron, Gamma Iron.
FERROALLOY
An iron-bearing product, not within the range of those called steels, which contains a considerable amount of one or more alloying elements, such as manganese, silicon, phosphorus, vanadium, chromium. Some of the more common ones are ferrochromium, ferromanganese, ferrophosphorus, ferrosilicon, ferrovanadium. The chief use of these alloys is for making additions of their respective alloying elements to molten steel.
FERROCHROME
A finishing material which contains about 70 pct chromium. It is used when it is desired to add chromium to steel.
FERROMANGANESE
A product of the blast furnace, containing, besides iron, 78 to 82 pct of manganese and some silicon, phosphorus, sulphur and carbon. It is used as a deoxidizer and for the introduction of manganese into steel.
FERROPHOSPHORUS
A finishing material (see "finishing") which contains about 18 pet phosphorus. It is used when it is necessary to add phosphorus to steel.
FERROSILICON
A product of the blast furnace which contains 8 to 15 pet silicon. It is used as a deoxidizer and for adding silicon to steel.
FERROUS METALLURGY
That section of general metallurgy which embraces the science and knowledge applying to iron and steel products, their preparation and adaptation to their numerous uses.
FERROVANADIUM
A product which contains iron and about 38 pct vanadium. Used as a finisher for adding vanadium to steel.
FIBER STRESS
Local stress at a point OF line on a section over which stress is not uniform, such as on the cross section of a beam under a bending load.
FIBER, FIBRE
1.) A characteristic of wrought metal that indicates directional properties and is revealed by the etching of a longitudinal section or is manifested by the fibrous or woody appearance of a fracture. Fiber is caused chiefly by the extension of the constituents of the metal, both metallic and nonmetallic, in the direction of working.

2.) The pattern of preferred orientation of metal crystals after a given deformation process (usually wiredrawing).
FINISH
In the steel industry, refers to the type of surface condition desired or existing in the finished product.
FINISHED STEEL
Steel that is ready for the market without further work or treatment. Blooms, billets, slabs, sheet bars, and wire rods are termed "semifinished."
FINISHING TEMPERATURE
The temperature at Which hot mechanical working of metal is completed.
FLAME ANNEALING
A process of softening a metal by the application of heat from a high-temperature flame.
FLAME CUTTING
(1) Severing a piece of steel by burning a portion out by means of an oxyacetylene torch, or

(2) removing a part of the surface by means of the burning torch, as in conditioning. (More properly called "scarfing.")
FLAME HARDENING
A process of hardening a ferrous alloy by heating it above the transformation range by means of a high-temperature flame, and then cooling as required.
FLANGE
(1) A projection of metal on formed objects.

(2) The parts of a channel at right angles to the central section or web.
FLARE TEST
A tapered expansion over a cone having various degrees and of various lengths.
FLASH
A thin fin of metal formed at the sides of a forging or weld when a small portion of metal is forced out between the edges of the forging or welding dies.
FLATTENING
Standard commercial flatness is obtained by roller leveling. This consists in passing sheets singly or in packs through a machine having a series of small diameter rolls.
FLATTENING TEST
It is Customary to take a ring or crop end from the tube or pipe, position the weld either 0º or 90º to the applied force and flatten between paralleled plates, without cracking or showing flaws. Usually test specimens are flattened to 5 times the wall thickness.
FLOATING LOAD
A load carried on and attached to skids which are free to slide longitudinally under traffic shocks. Lateral movement is prevented by lumber fastened to the car floor.
FLOATING PLUG
A plug that locates itself inside a tube during drawing, in such a way that the tube is reduced in thickness between the plug and the die.
FLOW STRESS
The shear stress required to cause plastic deformation of solid metals.
FOG QUENCHING
A method of quenching in which a fine vapor or mist is used as the quenching medium.
FORMING
To shape or fashion with the hand or tools or by a shape or mold.
FORMING PROPERTIES
Those physical and mechanical properties that allow a steel to be formed without injury to the steel in the finished product.
FRACTURE STRESS
The maximum principal true stress (fracture load divided by fracture area.)
FRACTURE TEST
Breaking a piece of metal for the purpose of examining the fractured surface to determine the structure or carbon content of the metal or to detect the presence of internal defects.
FULL ANNEALING
A softening process in which a ferrous alloy is heated to a temperature above the transformation range and, after being held for a sufficient time at this temperature, is cooled slowly to a temperature below the transformation range. The alloy is ordinarily allowed to cool slowly in the furnace, although it may be removed and cooled in some medium that ensures a slow rate of cooling.
FUSION WELDING
A term which refers to the union of metals by fusion, using acetylene blow-pipe, electric current or the thermit reaction.

G

GAGE, WORKING
The gage used by the workman in inspecting the product. Tested periodically by the reference gage.
GAGES
A measurement of thickness. There are various standard gages such as United States Standard Gage (USS), Galvanized Sheet Gage (GSG), Birmingham Wire Gage (BWG).
GALVANIZING
The process of applying a coating of zinc to the finished tube. The coating is applied by hot dipping or electrolytic deposition.
GALVANNEALED
An extra tight coat of galvanizing metal (zinc) applied to a soft steel sheet, after which the sheet is passed through an oven at about 1200° F. The resulting coat is dull gray without spangle especially suited for subsequent painting.
GAS CUTTING
Cutting material with gas torch rather than by shearing. This operation may set up undesirable stresses in the material near the cut edges due to thermal effects; such stresses can be relieved by suitable heat treatment. Same as flame cutting.
GAS CYANIDING
Synonymous with carbonitriding.
GRAIN SIZE
In many nonferrous metals, particularly alpha brasses, grain size is expressed in millimeters average diameter and is determined by comparison with standards as 75 diameters in magnification. The grain size may also be expressed in terms of the number of grains per unit area or volume.
GRAINS
Individual crystals in metals.
GRAPHITIZING
A heating and cooling process by which the combined carbon in cast iron or steel is transformed, wholly or partly, to graphitic or free carbon.

H

HAND TIGHT
Couplings tightened by hand with such effort as an average man can continuously exert. It does not refer to such forcings as can be done by a man picked for his strength.
HARDENABILITY
In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.
HARDNESS
Defined in terms of the method of measurement.

            (1) Usually the resistance to indentation.

            (2) Stiffness of temper of wrought products.

            (3) Machinability characteristics.
HEAT TREATING FILM
A thin oxide coating or film formed on the surface of metals during thermal treatments.
HEAT TREATMENT
A combination of heating and cooling operation, timed and f applied to a metal or alloy in the solid state in a way that will produce desired properties. Heating for the sole purpose of hot working is excluded from the meaning of this definition.
HIGII STRENGTH STEEL
Low alloy steels forming a specific class in which enhanced mechanical properties and, in most cases, good resistance to atmospheric corrosion are obtained by the incorporation of moderate proportions of one or more alloying elements other than carbon. The preferred terminology is now "high-strength, low-alloy steels."
HOMOGENEOUS
Usually defined as having identical characteristics throughout. However, physical homogeneity may require only an identity of lattice type throughout while chemical homogeneity requires uniform distribution of alloying elements.
HOMOGENIZING TREATMENT
A heat treatment, usually for a long time at a high temperature, designed to make metal chemically homogeneous.
HOT FORMING
Working operations, such as bending and drawing sheet and plate, forging, pressing, and heading, performed on metal heated to temperatures above room temperature.
HOT QUENCHING
A process of quenching in a medium at a temperature substantially higher than atmospheric temperature.
HOT SHORTNESS
Brittleness in hot metal.
HOT WORKING
Plastic deformation of metal at such a temperature and rate that strain hardening does not occur. The lower limit of temperature for this process is the recrystallization temperature.

I

IMMERSION COATING
Coating a metal with a second metal by immersing the first in a solution containing ions of the second.
IMPACT EXTRUSION
A cold forming process in which the metal is forced by impact to flow around the punch, forming a tube with a solid bottom.
IMPACT TEST
A test to determine the energy absorbed in fracturing a test bar at high velocity. The test may be in tension or in bending, or it may properly be a notch test if a notch is present, creating multiaxial stresses.
INCLUSIONS
Particles of non-metallic impurities, usually oxides, sulphides, silicates, and such, which are mechanically held in steel during solidification.
INDENTATION HARDNESS
The resistance of a material to indentation. This is the usual type of hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load.
INDIRECT EXTRUSION (INVERTED)
An extrusion process in which the metal is forced back inside a hollow ram that pushes the die.
INDUCTION HARDENING
A process of hardening a ferrous alloy by heating it above the transformation range by means of electrical induction, and then cooling as required.
INDUCTION HEATING
A process of heating by electrical induction.
INITIAL CREEP
The early part of the time — elongation curve for creep, in which extrusion increases at a rapid rate.
INTERANGULAR CORROSION
A type of electrochemical corrosion that progresses preferentially along the grain boundaries of an alloy, usually because the grain boundary regions contain material anodic to the central regions of the grain.
INTERCRYSTALLINE CRACKING
Cracks of fractures that follow along grain boundaries in the microstructure of metals and alloys.
INTERNAL SOUNDNESS
Refers to condition of inside of material —lack of defects, pipe, segregation, non-uniformity of composition.
INTERRUPTED QUENCHING
A process of quenching in which the metal object being quenched is removed from the quenching medium while the object is at a temperature substantially higher than that of the quenching medium.
INTRACRYSTALLINE FAILURES
Fractures across the grains in metal.
ISOTHERMAL ANNEALING
A process in which a ferrous alloy is heated to produce a structure partly or wholly austenitic, and is then cooled to and held at a temperature that causes transformation of the austenite to a relatively soft ferrite-carbide aggregate.

K

KILLED STEEL
Steel deoxidized with a strong deoxidizing agent such as silicon or aluminum in order to reduce the oxygen content to a minimum so that no reaction occurs between carbon and oxygen during solidification.
KILLED, SEMI-KILLED, AND RIMMED STEEL
The factors governing steel ingot structures are influenced in degree or extent by various conditions singly or in combination, some of which are temperature and chemical composition of both metal and slag, rate of pouring, and size and shape of ingot molds. The control of such interrelated conditions has been the object of extended research and experimental work.

The manufacture of steel from raw materials is an oxidizing process, and the molten metal as it comes from the furnace contains more or less oxygen in the form of dissolved oxides, the amount varying with the composition desired, and with certain conditions of steel making.

If certain elements such as manganese, silicon or aluminum are added in sufficient amounts to molten metal in the furnace, in the ladle, or in the ingot mold, the metal will solidify quietly without evolution of gases.

L

LADLE ANALYSIS
The term applied to the chemical analysis representative of a heat blow of steel and is the analysis reported to the purchaser. It is determined by analyzing (for such elements as have been specified) a test ingot sample obtained from the first part or middle part of the heat or blow during the pouring of the steel from a ladle.
LAMINATIONS
Defects resulting from the presence of blisters, seams or foreign inclusions aligned parallel to the worked surface of a metal.
LAP
A surface defect appearing as a seam caused from folding over, during hot rolling, fins or sharp corners and then rolling or forging, but not welding, them into the surface.
LAP WELD
A term applied to a weld formed by lapping two pieces of metal and then pressing or hammering, and applied particularly to the longitudinal joint produced by a welding process for tubes or pipe, in which the edges of the skelp are beveled or scarfed so that when they are over-lapped they can be welded together.
LENGTHS
Tubular products are furnished

            (1) random lengths as produced on the mill,

            (2) in average lengths, falling between specified minimum and maximums,

            (3) in definite cut-lengths,

            (4) multiple lengths, each suitable for cutting into a definite number of short pieces, or

            (5) in welded double-lengths, meaning two lengths welded together, in order to produce desired long lengths.
LONGITUDINAL DIRECTION
The direction in a wrought metal product parallel to the direction of working (drawing, extruding, rolling).
LONGITUDINAL TEST
This term should be used only in connection with test specimens, both tension and bend, and to indicate that their longitudinal axis is parallel to the direction of greatest extension of the material from which they are cut. The stresses applied to both the tension and bend test specimens will be in the direction of their longitudinal axis. In speaking of bending flat-rolled products longitudinally, it is understood that the bend or fold runs parallel to the direction of greatest extension of the material in rolling (i.e., with the grain). This means, of course, that the direction of this bend is at right angles to the fold in a longitudinal bend specimen.

M

MACHINE STRAIGHTENING
The straightening of the material, which irregularities of the rolling and cooling often make necessary, is done in roll straighteners or machine straighteners, or by means of gag presses.
MACHINING
In general, the cutting away of the surface of a metal by means of power driven machinery. Specifically, a method of conditioning steel by machining away the surface. See Turning: Conditioning.
MACROETCH
A testing procedure for porosity, pipes, bursts, unsoundness, inclusions, segregations, carburization, flow lines from hot working, etc. Surface of the test piece should be reasonably smooth or even polished. After applying a suitable. etching solution, the structure developed by the action of the reagent may be observed.
MACROGRAPH
A photographic reproduction of any object that has not been magnified more than ten times.
MACROSCOPIC
Visible either with the naked eye or under low magnification (as great as about 10 diameters).
MACROSCOPIC DEEP ETCH TEST
Referred to as the porosity test. The test piece is heavily etched in HCI at 180 degrees F. and then closely examined under magnification for the detection of hammer bursts, pipe, seams, laps, checks, flakes. A light etch is employed to detect soft spots, depth of case, etc.
MACROSCOPIC STRESSES
Residual stresses of such scope that relatively large areas of the material or the whole specimen are involved. These stresses are accompanied by strain measurable with ordinary extensometers under appropriate test conditions.
MACROSTRUCTURE
The structure and internal condition of metals arc revealed on a ground or polished (and usually etched) sample, by either the naked eye or under low magnification (up to about 10 diameters).
MAGNAFLUX
An inspection given to important or highly stressed parts of aircraft quality steel using alloy. It consists in suitably magnetizing the material and applying a prepared magnetic powder which adheres to it along lines of flux leakage. It shows the existence of surface and subsurface nonuniformities.
MALLEABILITY
The property that determines the ease of deforming a metal when the metal is subjected to rolling or hammering. The more malleable metals can be hammered or rolled into thin sheet more easily than others.
MALLEABILIZING
A process of annealing white cast iron in such a way that the combined carbon is wholly or partly transformed to graphitic or free carbon or, in some instances, part of the carbon is removed completely.
MANDREL
(1) A rod used to retain the cavity in hollow metal products during working.

(2) A metal bar around which other metal may be cast, bent, formed or shaped.
MARTEMPERING
The process of quenching an austenitized ferrous alloy in a medium at a temperature in the upper portion of the temperature range of martensite formation, or slightly above that range, and holding in the medium until the temperature throughout the alloy is substantially uniform. The alloy is then allowed to cool in air through the temperature range of martensite formation.
MARTENSITE
An unstable constituent in quenched steel, formed without diffusion and only during cooling below a certain temperature. The structure is characterized by its acicular appearance on the surface of a polished and etched specimen. Martensite is the hardest of the transformation products of austentite. Tetragonality of the crystal structure is observed when the carbon content is greater than about 0.5 %.
MAXIMUM CORE LOSS
That part of the electrical energy required to magnetize a core of magnetic material that is dissipated as heat generated within the core, as distinguished from the energy lost in the coil surrounding the core. Core loss is made up of two components: hysteresis and eddy current losses.
MECHANICAL METALLURGY
The science concerned with the relationships among the measured mechanical properties of metals and their mechanical behavior in service, and with the way these properties and service characteristics vary with chemical composition, structure and temperature. The field also includes mechanical processing such as rolling, drawing and the like.
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; for example, the modulus of elasticity, tensile strength and fatigue limit. These properties have often been designated as "physical properties," but the term "mechanical properties" is much to be preferred.
MECHANICAL TUBING
Used for a variety of mechanical and structural purposes as opposed to pressure tubing which is used for the conduction of fluids under pressure. It is commonly manufactured to consumer specifications covering chemical analysis, physical properties and often to special dimensional tolerances. It is used for such a variety of purposes that it is impractical to subdivide it into classifications such as are used for other classes of tubing.
MECHANICAL WORKING
Subjecting metal to pressure exerted by rolls, dies, presses, or hammers, to change its form or to affect the structure and consequently the mechanical and physical properties.
METALLOGRAPHY
The science concerning the constitution and structure of metals and alloys as revealed by the microscope.
METALLURGY
The science which deals with the extraction of metals from their ores and the adaptation and application of these metals to the uses for which they are intended.
MICROCLEANLINESS
Refers to the extent or quantity of nonmetallic inclusions observed by examination under a microscope.
MICROSCOPIC TESTS
Tests used in studying inclusions, segregation and structure. Microscopic studies may be supplemental and coordinated with other tests.
MILL FINISH
A surface finish produced on sheet and plate, characteristic of the ground finish on the rolls used in fabrication.
MILLING
The mechanical treatment of material, as in a ball mill, to produce particles or alter their size or shape, or to coat one component of a powder mixture with another.
MODULUS OF ELASTICITY
The slope of the elastic portion of the stress-strain curve in mechanical testing. The stress is divided by the unit elongation. The tensile or compressive elastic modulus is called "Young's modulus"; the torsional elastic modulus is known as the "shear modulus"; or "modulus of rigidity."
MODULUS OF RIGIDITY
In a torsion test, the ratio of the unit shear stress to the displacement caused by its per unit ,length in the elastic range. This modulus corresponds to the modulus of elasticity in the tension test.
MODULUS OF RUPTURE
The ultimate strength or the breaking load per unit area of a specimen tested in torsion or in bending (flexure). In tension, it is the tensile strength.
MOLYBDENUM
A special alloying element commonly used to increase hardenability of steel. Molybdenum is sometimes added to stainless steel to enhance its corrosion resistance to certain chemicals. Molybdenum is commonly called "moly."
MOMENT OF INERTIA
It is not practical to provide an adequate definition of this term within the scope of this handbook. Reference to a recognized engineering handbook or textbook is suggested.

N

NECKING DOWN
The narrowing, or constricting to a smaller cross-sectional area, which occurs at a localized place on a tensile test piece while it is being pulled.
NITRIDING
A process of case hardening in which a ferrous alloy, usually of special composition, is heated in an atmosphere of ammonia or in contact with nitrogenous material to produce surface hardening by the absorption of nitrogen, without quenching.
NOMINAL SIZE
The diameter listed for the various sizes of pipe which, of course, is subject to variation either way as permitted in specification.
NORMALIZE
The normalizing process which is commonly applied to steel articles of heavy section consists of: heating to a temperature about 100° F. above the critical range and cooling in still air.
NOTCH BRITTLENESS
Susceptibility of a material to brittleness in areas containing a groove, scratch, sharp fillet or notch.
NOTCH SENSITIVITY
The reduction caused, in nominal strength, impact or static, by the presence of a stress concentration, usually expressed as the ratio of the notched to the unnotched strength.

O

OILED
Application of a suitable oil to final product to retard rusting. Where surface is a consideration, it is also desirable in reducing friction scratches that may develop in transit. The oil coating is not intended to serve as a lubricant for subsequent fabrication.
OPERATING STRESS
The stress to which a structural unit is subjected during service.
OVALITY
The difference between the maximum and minimum diameters of any one section of tube.
OVERBENDING
Allowance for spring-back when bending metal to a desired angle.
OVERHEATED
A term applied when, after exposure to an excessively high temperature, a metal develops an undesirably coarse grain structure but is not permanently damaged. Unlike a burnt structure, the structure produced by overheating can be corrected by suitable heat treatment, by mechanical work, or by a combination of the two.
OVERSTRESSING
Permanently deforming a metal by subjecting it to stresses that exceed the elastic limit.
OXIDE
Usually refers in the steel industry to oxide of iron, of which there are three principal ones: FeO, Fe3O4, Fe2O3. In addition, there are many mixtures of these oxides which form on the surface of steel at different temperatures and give the steel different colors, such as yellow, brown, purple, blue and red. Oxides must be thoroughly removed from the surface of steel objects which are to be coated with tin, zinc, or other metals. See Scale.

P

PACKAGE
A bundle or a number of bundles, secured into a single unit.
PACKAGING
Refers, in the steel industry, to most economical and safest method of grouping finished or semi-finished steel products for loading and transporting to the customer.
PASS
1. Movement of a piece of steel through a stand of rolls.

2. The open space between two grooved rolls through which is rolled the steel which is being processed.
PERMANENT SET
Inelastic deformation.
PERMEABILITY
1. Magnetic permeability, the ratio of the magnetic induction to the intensity of the magnetizing field.

2. In a mold, the porosity of foundry sands and the ability of trapped gases to escape through the sand.
PHOTOMICROGRAPH
A photographic reproduction of any object magnified more than 10 diameters. The term micrograph may be used.
PHYSICAL PROPERTIES
Those properties familiarly discussed in physics, exclusive of those described under mechanical properties; for example, density, electrical conductivity, coefficient of thermal expansion. This term has often been used to describe mechanical properties, but this usage is not recommended. See mechanical properties.
PHYSICAL TESTING
Testing methods by which physical properties are determined. This term is also used inadvisedly to mean the determination of the mechanical properties.
PICKLE
Chemical or electrochemical removal of surface oxides.
PIPE
A cavity formed by contraction in metal (especially ingots) during solidification of the last portion of liquid metal.
PIT
A sharp depression in the surface of metal.
PLASTIC DEFORMATION
Permanent distortion of a material under the action of applied stresses.
PLASTICITY
The ability of a metal to be deformed extensively without rupture.
PLUG
A rod or mandrel that fills a tube as it is drawn through a die.
POROSITY
Unsoundness caused in cast metals by the presence of blowh
PREHEATING
1. A general term used to describe heating applied as a preliminary to some further thermal or mechanical treatment.
2. A term applied specifically to tool steel to describe a process in which the steel is heated slowly and uniformly to a temperature below the hardening temperature and is then trans ferred to a furnace in which the temperature is substantially above the preheating temperature.
PRESSURE 'TUBES
As distinguished from pressure piping are used to conduct fluids under pressure or at elevated temperatures or both and are suitable for the external application of heat. Subdivisions of this classification include boiler tubes, super-heater tubes, oil-still tubes, heat exchanger and condenser tubes.
PRIMARY SCALE
Oxide of iron (Fe3O4) which is formed while the steel is being heated.
PRINCIPAL STRESSES
Normal stresses along rectilinear co-ordinates that are so chosen in direction that shearing stresses are zero.
PROCESS ANNEALING
In the sheet and wire industries, a process by which a ferrous alloy is heated to a temperature close to, but below, the lower limit of the transformation range and is subsequently cooled. This process is applied in order to soften the alloy for further cold working.
PROOF STRESS
In a test, stress that will cause a specified permanent deformation in a material, usually 0.01 pct or less.
PROOF TEST
Any type of test to indicate that the material or structure is suitable for the purpose intended.
PROPORTIONAL LIMIT
The greatest stress a material is capable of sustaining without a deviation from the law of proportionality of stress and strain. If the load is removed for any stress up to this point, the material will spring back, or assume its original dimensions.

Q

QUALITY
Refers to the suitableness of the steel for the purpose or purposes for which it is intended.
QUENCH HARDENING
A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and cooling at a rate sufficient to increase the hardness substantially. The process usually involves the formation of martensite.
QUENCHING
A process of rapid cooling from an elevated temperature by contact with liquids, gases or solids.
QUENCHING CRACK
A fracture resulting from thermal stresses_ induced during rapid cooling or quenching. Frequently encountered in alloys that have been overheated and liquated and are thus "hot short."

R

RADIOACTIVE METALS
A group of metals with high atomic weights and with atomic nuclei that decompose slowly, giving off continual radiations of positively charged alpha particles, which are relatively slow; negatively charged beta particles, which are faster and lighter; and gamma rays. The gamma rays are similar to X-rays but are more penetrating and are used for radiography of very thick sections. Bombardment by neutrons can make any metal radioactive and small concentrations of such metals are used as "tracers" in the study of diffusion and other phenomena.
RANGE
The term range as used in connection with chemical or physical properties, lengths, tolerances, etc., is the numerical difference between the maximum and minimum of the given limits. Thus carbon 0.15 to 0.25 per cent is considered to be a ten-point range
REAMED
Means having the burr from cutting-off tool removed from inside, at ends, by a slight countersinking.
RECESSED
Counterbored for a short distance when applied to couplings.
REDUCTION OF AREA
The difference between the original cross-sectional area and that of the smallest area at the point of rupture; usually stated as a percentage of the original area; also called "contraction of area."
REFINING TEMPERATURE
A temperature, usually just higher than the transformation range, employed in the heat treatment of steel to refine the structure, in particular, the grain size.
RESIDUAL STRESS
Macroscopic stresses that are set up within a metal as the result of non-uniform plastic deformation. This deformation may be caused by cold working or by drastic gradients of temperature from quenching or welding.
RESILIENCE
'The tendency of a material to return to its original shape after the removal of a stress that has produced elastic strain.
RESISTANCE WELDING
A type of welding process in which the work pieces are heated by the passage of an electric current through the contact. Such processes include spot welding, seam or line welding and percussion welding. Flash and butt welding are sometimes considered as resistance welding processes.
RIMMED STEEL
A low-carbon steel which (a) is effervescent when cast and during a considerable part of its solidification; (b) neither rises nor falls in the mold to any marked extent; (c) when completely solidified has no pipe, but has blowholes both centrally located and deep seated below the surface; (d) has been cleansed from some of the impurities and dirt because of their rising to the top during the agitation of the molten metal by the escaping gases; and (e) has a cross section divided into three fairly well defined zones:
1. A very clean thin outer layer of nearly the same chemical composition as when poured;
2. A central portion; and
3. An intermediate portion. The three zones are positively and negatively segregated with respect to metalloids.
NOTE: The term "rimmed" comes from the fact that during the gradual freezing inwards from the sides the molten portion at the top of the ingot becomes smaller and smaller and is said to "rim in" until finally the whole top is solidified.
ROLL FORMING
A process of coiling sheet into open cylinders (tubes).
ROLL TABLE
A conveyer-type table surface that contains a series of small rolls over which metal products pass during processing.
ROLLER STRAIGHTENING
A process involving a series of staggered rolls of small diameter, between which rod, tubing and shapes are passed for the purpose of straightening. The process consists of a series of bending operations.

S

SALT SPRAY TEST
An accelerated corrosion test in which the metal specimens are exposed to a fine mist of salt water solution either continuously or intermittently.
SAMPLING
The cutting or baring of samples for testing.
SCAB (SCABBY)
A blemish caused on a casting by eruption of gas from the mold face, or by uneven mold surfaces; or occurring where the skin from a blowhole has partly burned away and is not welded. They also result from splashing of molten metal on mold walls during teeming.
SCALE
An oxide of iron which forms on the surface of hot steel. Sometimes it forms in large sheets which fall off when the steel is rolled. See also Roll Scale.
SCARFING
Cutting surface areas of metal objects, ordinarily by using a gas torch. The operation permits surface defects to be cut from ingots, billets or the edges of plate that is to be beveled for butt welding. See Chipping.
SEAM
On the surface of metal, a crack that has been closed but not welded; usually produced by some defect either in casting or in working, such as blowholes that have become oxidized or folds and laps that have been formed during working. Seam also refers to lap joints, as in seam welding.
SEAM WELDING
An electric-resistance type of welding process, in which the lapped sheet is passed between electrodes of the roller type while a series of overlapping spot welds is made by the intermittent application of electric current.
SECONDARY HARDENING
Tempering certain alloy steel at certain temperatures so that a hardness is obtained greater than that resulting from the tempering of the same steel at some lower temperature for the same time.
SECTION MODULUS
It is not practical to provide an adequate definition of this term within the scope of this Handbook. Reference to a recognized engineering handbook or textbook is suggested.
SEGREGATION
The result of the natural phenomenon in the solidification of a steel ingot in which various components of the steel having the lowest freezing point are concentrated in parts of the ingot last to solidify.
SELECTIVE HEATING
A process by which only certain portions of an object are heated, in a way that will produce desired properties after cooling.
SELECTIVE QUENCHING
A process by which only certain portions of an object are quenched.
SEMI-KILLED STEEL
Steel incompletely deoxidized, to permit evolution of sufficient carbon monoxide to offset solidification shrinkage.
SHIELDED-ARC WELDING
Electric-arc welding in which the metal is protected from the air atmosphere. An inert gaseous atmosphere may be used or flux-coated electrodes.
SHORTNESS
Brittleness in metal.
SILVER SOLDERS
Alloys of silver, copper, zinc and other metals, melting between 600' and 1600°F. used for making strong joints that resist corrosion.
SINKING TUBING
Drawing tubing through a die without use of an interior tool.
SIZING
A final pressing of a sintered compact to secure the desired size.
SKELP
A plate of steel or wrought iron from which pipe or tubing is made by rolling the skelp into shape longitudinally and welding the edges together.
SLENDERNESS RATIO
Length of a test specimen divided by the square root of the cross-sectional area.
SOAK
To hold an ingot, slab, bloom, billet or other piece of steel in a hot chamber or pit to secure uniform temperature throughout. Freshly stripped ingots are hottest in the interior, whereas a cold object which is being heated is hottest at the surface. The term is used in connection with heating of steel whether for forging or rolling or for heat treatment.
SOLDERING
Joining metals by fusion of alloys that have relatively low melting points most commonly, lead-base or tin-base alloys, which are the soft solders. Hard solders are alloys that have silver, copper, or nickel bases and use of these alloys with melting points higher than 800° F. is generally termed brazing.
SOLUTION HEAT TREATMENT
A process in which an alloy is heated to a suitable temperature, is held at this temperature long enough to allow a certain constituent to enter into solid solution and is then cooled rapidly to hold the constituent in solution. The metal is left in a supersaturated, unstable state and may subsequently exhibit age hardening.
SPECTROGRAPH
An optical instrument for determining the presence or concentration of minor metallic constituents in a material by indicating the presence and intensity of specific wave lengths of radiation when the material is thermally or electrically excited.
SPRAY QUENCHING
After solution, a mode of quenching in which a spray of water is directed upon material just removed from the furnace. This method is more effective than fog quenching. Both methods are designed to reduce distortion that may attend water bath quenching.
STABILIZING ANNEAL
A treatment applied to austenitic stainless steels that contain titanium or columbium. This treatment consists of heating to a temperature below that of a full anneal in order to precipitate the maximum amount of carbon as titanium carbide or columbium carbide. This eliminates precipitation at lower temperatures, which might reduce the resistance of the steel to corrosion.
STABILIZING TREATMENT
A thermal treatment designed to precipitate material from solid solution, in order to improve the workability, to decrease the tendency of certain alloys to age harden at room temperature, or to obtain dimensional stability under service at slightly elevated temperatures.
STAINLESS
1. A trade name given to alloy steel that is corrosion and heat resistant. The chief alloying elements are chromium, nickel and silicon in various combinations with a possible small percentage of titanium, vanadium, etc.
2. By AISI definition, a steel is called "Stainless" when it contains 10.5 pct or more chromium.
STRAIGHTENING
The removal of sweep and camber by roller straightening or by use of the gag press.
STREAMLINE TUBING
Extruded or drawn tubing of which the cross section is shaped like a teardrop.
STRESS
The load per unit of area. Ordinarily stress-strain curves do not show the true stress (load divided by area at that moment) but a fictitious value obtained by using always the original area.
STRESS RELIEVING
A process of reducing residual stresses in a metal object by heating the object to a suitable temperature and holding for a sufficient time. This treatment may be applied to relieve stresses induced by casting, quenching, normalizing, machining, cold working or welding.
STRETCHER STRAIGHTENING
A process for straightening rod, tubing and shapes by the application of tension at the ends of the stock. The products are elongated a definite amount to remove warpage.
STRIPPING
Removing coated or electrolytically deposited metal or oxides from the base.
SURFACE CHECKING
General breaking and cracking of the surface, which may result from a variety of causes, such as overrolling, overforming, or atmospheric attack at grain boundaries.
SURFACE INSPECTION
The inspection of the surface of products for defects such as ingot cracks, scabs, seams, burned Steel, laps, twist, guide marks, etc.
SWAGED
Reduced in diameter by use of blacksmith's swages or swedges, hence the name. This is a hammering process, but the same result may be attained by press forging or spinning.

T

TEMPER
A condition produced in a metal or alloy by mechanical or thermal treatment and having characteristic structure and mechanical properties. A given alloy may he in the fully softened or annealed temper, or it may be cold worked to the hard temper, or further to spring temper. Intermediate tempers produced by cold working (rolling or drawing) are called "quarter-hard," "half-hard" and "three-quarters hard," and are determined by the amount of cold reduction and the resulting tensile properties. In addition to the annealed temper, conditions produced by thermal treatment are the solution heat treated temper and the heat treated and artificially aged temper. Other tempers involve a combination of mechanical and thermal treatments and include that temper produced by cold working after heat treating, and that produced by artificial aging of alloys that are as-cast, as-extruded, as-forged and heat treated, and worked.
TEMPERING
A process of reheating quench-hardened or normalized steel to a temperature below the transformation range, and then cooling at any rate desired.
TENSILE STRENGTH
The value obtained by dividing the maximum load observed during tensile straining until breakage occurs by the specimen cross-sectional area before straining. Also called "ultimate strength."
TERNARY ALLOY
An alloy that contains three principal elements.
TERNEPLATE
Steel sheet, hot dip coated with terne metal (10-15 pct tin; 85-90 pct lead).
THERMAL STRESSES
Stresses in metal, resulting from nonuniform distribution of temperature.
THERMAL TREATMENT
Any treatment listed under annealing or heat treating.
TITANIUM
A metal which is commonly added to chrome nickel stainless steel to improve its welding properties. So used, it is called a "stabilizer" or is said to prevent "carbide precipitation." The amount of titanium commonly used for this purpose is 5 to 7 times the carbon content.
TORSION
Strain created in a material by a twisting action. Correspondingly, the stress within the material resisting the twisting.
TRANSFORMATION RANGE OR TRANSFORMATION TEMPERATURE RANGE
The temperature interval within which austenite forms while ferrous alloys are being heated. Also the temperature interval within which austenite disappears while ferrous alloys are being cooled. The two ranges are distinct, sometimes overlapping but never coinciding. The limiting temperatures of the ranges depend on the composition of the alloy and on the rate of change of temperature, particularly during cooling.
TRANSFORMATION TEMPERATURE
The temperature at which a change in phase occurs. The term is sometimes used to denote the limiting temperature of a transformation range.
TRANSVERSE TEST
This term should be used only in connection with test specimens, both tension and bend, and to indicate that their longitudinal axis is perpendicular to the direction in which the material from which they are cut is most drawn out. Although the stress applied to the transverse specimens will be in the direction of their longitudinal axis, this stress is at the right angles to the longitudinal axis of the material. In speaking of bending flat-rolled products transversely it is understood that the bend or fold runs crosswise of the direction in which the material is most drawn out (i.e., across the grain).
TUBE REDUCER
A machine in which a pair of rolls is used for cold rolling tubing and rod. These rolls have a tapered groove around part of their surface, corresponding to the intended change in outside dimension of the tube or rod. The stock is rotated between working strokes. This process is somewhat different from the Pilger Process in that the stock moves in the same direction, as rolling proceeds; the axes of the rolls move back and forth parallel to the stock; and the direction of rotation of the rolls changes between the forward working stroke and the backward return stroke. A fixed mandrel is used in rolling tubing.
TUBING
Tubing can be defined as a tubular product generally manufactured to specified dimensions, tolerances, chemistry, mechanical properties and other specifications (including surface) required for definite applications in aircraft, sanitary, mechanical, pressure, ornamental or structural uses. It is generally specified to two dimensions, i.e., O.D. (Outside Diameter) and wall, I.D. (Inside Diameter) and wall, or O.D. and I.D. It is not primarily designed for use with standard threaded pipe couplings or for applications where standard or heavy wall pipe is normally used.

U

ULTIMATE STRENGTH
The greatest load per square inch of original cross-sectional area carried during a tension test to failure. The term "ultimate strength" is preferred to "tensile strength."
UPSET
The product of any cold or hot forming of material in which the metal is thickened by being forced back into itself. It is usually done at a red heat by hammering or press forging. Upset tubes are those whose ends have their walls so thickened for a short distance; usually to such an extent that the threading leaves as great a thickness of metal below roots of threads as in main body of tubes. Upset tubes are much used as stay tubes; they are sometimes called stove tubes.

V

VISCOSITY
The resistance of fluid substance to flowing, quantitatively characteristic for each individual substance at a given temperature and under other definite external conditions.

W

WELD BEAD
The built-up portion of a fusion weld, formed either from the filler metal or from the melting of the parent metal.
WELDING
A process used to join metals by the application of heat. Fusion welding, which includes gas, arc and resistance welding, requires that the parent metals be melted. This distinguishes fusion welding from brazing. In pressure welding, joining is accomplished by the use of heat and pressure without melting. The parts that are being welded are pressed together and heated simultaneously, so that recrystallization occurs across the interface.
WELDING STRESS
The stress resulting from localized heating and cooling of metal during welding.
WOODY FRACTURE
A descriptive term for fracture of sound, though dirty steel, frequently also reedy or conchoidal in appearance, and often containing discernible slag particles. Woody fractures sometimes contain many small slivery areas, too numerous and small to be correctly termed "flakes" and of a different nature.
WORK HARDNESS
Hardness developed in metal as a result of cold working. See Cold Working.
WORKABILITY
The characteristic or group of characteristics that determines the ease of forming a metal into desired shapes.
WROUGHT IRON
Hardness developed in metal resulting from mechanical working, particularly cold working.

Y

YIELD POINT
In mild or medium-carbon steel, the stress at which a marked increase in deformation occurs without increase in load. In other steels and in nonferrous metals this phenomenon is not observed. See Yield Strength.
YIELD STRENGTH
The stress at which a material exhibits a specified limiting deviation from proportionality of stress to strain. An offset of 0.2 pct is used for many metals such as aluminum base

Technical Reference Library

Glossary of Tube Terms

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B

C

D

E

F

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H

I

K

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M

N

O

P

Q

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U

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Y