- Age Hardening
See heat treatment.
- Air Frame Tubing
This tubing is produced for aircraft structural parts. This
tubing is made to special surface quality, mechanical properties
and other characteristics required by Military Specifications
(MIL-T...) and SAE Aeronautical Materials Specifications (AMS
- Air Hardening
See heat treatment.
- Aircraft Quality
Is a steel which has a special cleanliness rating determined by
magnetic particle testing. The terms Aircraft Quality and Magnaflux
Quality are considered synonymous.
- Alloy Steel
All steels contain carbon and small amounts of silicon, sulfur,
manganese and phosphorus. Steels which contain intentional
additions of elements other than these, or in which silicon and
manganese are present in large amounts for the express purpose of
improving or altering any of the physical or mechanical properties
of the steel, are termed alloy steels.
Heating and holding to a suitable temperature and then cooling
at a suitable rate, for such purposes as reducing hardness,
improving machinability, facilitating cold working, producing a
desired microstructure, or obtaining desired mechanical, physical
or other properties. See also heat treatment.
- Austenitic Stainless Steel
Low carbon, iron-chromium-nickel stainless alloys containing
more than 16% chromium, and 4 to 22% nickel to provide an
austenitic structure at normal temperatures. These alloys cannot be
hardened by heat treatment, but can be hardened by cold working.
They are normally non-magnetic in the annealed condition, but can
become slightly magnetic after cold working depending upon
- Average Wall
- Bearing Quality Steels
Steels suitable for use in balls, rollers and races of high
quality anti-friction bearings.
An angular cut on the I.D. or OD of a tube
As used in the manufacture of seamless tubes, a round bar with
dimensions and other characteristics suitable for piercing into
A semi-finished piece of steel, resulting from the rolling or
forging of an ingot. A bloom is square and not more than twice as
wide as thick; usually not less than 36 sq. in. in cross-sectional
An optical device used for inspecting under low magnification
the inside surface of tubes.
- Bright Anneal
See heat treatment.
- Brinell Hardness
The amount of curvature or deviation from exact straightness
over any specified length of tubing.
- Capped Steel
Semi-killed steel that has characteristics similar to those of
rimmed steels but to a degree intermediate between rimmed and
killed steel. The capping operation limits the time of gas
evolution and prevents the formation of an excessive number of gas
voids within the ingot.
A compound consisting of carbon and other elements.
- Carbide Precipitation
The phenomenon of carbides coming out of a solid solution,
occurring in stainless steel when heated into the range of 800-1600
- Carbon Steel
A steel consisting of essentially iron, carbon, manganese, and
silicon. Carbon steel has no minimum content required for aluminum,
chromium, cobalt, columbium, molybdenum, nickel, titanium,
tungsten, vanadium, zirconium or any other element added to obtain
alloying effect. Small quantities of certain residual elements are
Adding carbon to the surface of iron-base alloys by heating the
metal below its melting point in contact with carbonaceous solids,
liquids or gases. Desired hardness and toughness properties are
developed in the high carbon case by quenching and tempering.
- Case Hardening
A heat treatment in which the surface (case) of an iron-base
alloy is made harder than the interior (core). Any of the following
methods may be employed: flame hardening, induction hardening,
carburizing, cyaniding or nitriding.
(1) A beveled surface to eliminate an otherwise sharp corner.
(2) A relieved angular cutting edge at a tooth corner.
Impact Test A pendulum-type single blow impact test in which the
specimen, usually notched, is supported at both ends as a simple
beam and broken by a falling pendulum. The energy absorbed, as
determined by the subsequent rise of the pendulum, is a measure of
impact strength or notch toughness. See also impact testing.
- Check Analysis
An analysis of the metal after it has been rolled or forged into
semi-finished or finished forms. It is not a check on the ladle
analysis, but is a check against the chemistry ordered.
- Chloride Stress Cracking
See Stress Corrosion Cracking.
The amount of metal removal required to obtain desired
dimensions and complete removal of inherent surface
- Coefficient of Thermal Expansion
A physical property value representing the change in length per
unit length, the change in area per unit area or the change in
volume per unit volume per one degree increase in temperature.
- Cold Drawing
A process in which tubing is drawn at room temperature through a
die and over a mandrel to achieve its final size and to provide
better surface finish, closer tolerances, lighter walls, smaller
diameters, longer lengths, or a different combination of mechanical
properties from those possible through hot finishing or direct
- Cold Reduction
The reduction of sectional dimensions of a tube by any of a
number of types of cold-working operations.
- Cold Sinking
Similar to cold drawing, except that the tube is drawn through a
die, but without an internal mandrel, Usually used only for making
heavy wall or small tubing, where drawing over a mandrel is
impractical. Only outside diameter is closely controlled.
- Cold Working
Permanent plastic deformation of a metal below its
The removal of surface defects (seams, laps, pits, etc from
steel. Conditioning is usually done when the steel is in
semi-finished condition (bloom, billet, slab). It may be
accomplished, after an inspection, by chipping, scarfing, grinding,
Chemical or electrochemical deterioration of a metal or
- Corrosion (Galvanic)
Corrosion associated with the presence of two dissimilar metals
in a solution (electrolyte). In principle, it is similar to
bath-type plating in the sense that the anode surface has lost
- Corrosion (Intergranular)
Corrosion which occurs preferentially along the grain boundaries
of the alloy.
- Corrosion (Pitting)
Non-uniform corrosion usually forming small cavities in the
- Corrosion Resistance
The ability to resist attack by corrosion.
- Creep Strength
The constant nominal stress that will cause a specified quantity
of creep in a given time at a constant temperature. It is a measure
of a tube's ability to withstand prolonged stress or load without
significant continuous deformation. In steels it is an important
factor only at elevated temperatures.
Crown, in plates, sheet, or strips; characterized by a greater
thickness in the middle than at the edges. It may be caused by a
deflecting (bending) of the rolls or by worn rolls,
- Cut Length
Refers to tubing ordered to a specified length and permitting a
tolerance of a standardized fraction of an inch over but nothing
under the specified length.
A process in which an iron-base alloy is heated in contact with
a cyanide salt so that the surface absorbs carbon and nitrogen.
Cyaniding is followed by quenching and tempering to produce a case
with a desired combination of hardness and toughness.
The loss of carbon from the surface of an iron-base alloy as the
result of heating in an environment which removes the carbon. In
medium or high carbon steels, decarburization leads to a pronounced
lowering of the fatigue limit.
The mass per unit volume of a substance, usually expressed in
the tubing industry in pounds per cubic inch.
- OD - Outside Diameter. Specified in inches and fractions of an
inch, or inches and decimals of an inch. OD = (2 * Wall) + ID
- ID - Inside Diameter. Specified in the same units as the OD. ID
= OD (2 x Wall)
- Wall - Wall Thickness or Gage. Specified in either fractions or
decimals of an inch or by a wire gage number. In the United States,
the most common gage used for tubing is the Birmingham iron wire
gage, designated BWG. Wall = (OD*ID) / 2
- Nominal - The theoretical or stated value of the OD, ID or wall
dimension as specified by the customer.
- Maximum and Minimum - The dimensions resulting after applying
the proper tolerances to the nominal dimensions.
- Minimum Wall - Generally, the lightest wall permitted within
specified tolerances. A minimum wall tube is one whose wall
thickness is not permitted to fall below the specified nominal
- Average Wall - A tube whose wall thickness is permitted to
range over or under the specified nominal wall measurement within
certain defined tolerances.
- Duplex Stainless Steels
Contains a mix of austenite and ferrite that yields
significantly higher yield strength and improved stress corrosion
cracking resistance vs. T 304. Duplex stainless steels are
The ability of a tube to deform plastically. Frequently,
elongation during tensile testing is used as a measurement of this
- Dye Penetrant Inspection
Non-destructive test employing dye or fluorescent chemical and
sometimes black light to detect surface defects.
The displacement of the ID of the tube with respect to its OD
Eccentricity results in the variation of wall thickness.
- Eddy Current
Non-destructive testing method using eddy current flow for the
purpose of recognizing a discontinuity in the piece being
- Elastic Limit
A measure of the maximum stress that may be applied to a tube
without leaving a permanent deformation or strain after the stress
- Electric Furnace Process
One of the common methods used for melting and refining
stainless and some alloy steels. It involves the use of electric
power as the sole source of heat, thereby preventing contamination
of the steel by impurities in the fuel as in other melting
- Electric Resistance Welded Tubing Carbon steel tubing made from
strip by electric resistance heating and pressure, the strip being
part of the electrical circuit. The electric current, which may be
introduced into the strip through electrodes or by induction,
generates the welding heat through the electrical resistance of the
- As Welded Hot Rolled - ERW tubing exhibiting the pickled
surface of hot rolled strip.
- As Welded Cold RoIled - ERW tubing exhibiting the surface of
cold rolled strip.
- As Drawn tubing is unheat-treated, cold drawn tubing and has a
scale free cold drawn surface.
- Bright Annealed - Welded tubing normalized in a controlled
atmosphere furnace and which exhibits a bright surface.
- Pickled tubing has had the scale from hot fabrication or heat
treatment removed by one of several types of acid solutions.
- Gun Metal Finish - Welded tubing normalized, annealed, or
stress relieved in a controlled atmosphere furnace that exhibits a
gun metal finish. Flash-In tubing is welded tubing which still
retains the ID bead or flash formed during the welding operation.
It can be furnished in either the as-welded, sunk or heat-treated
- Flash-Removed - Welded tubing from which the ID flash formed
during the welding operation has been removed by some mechanical
method. It can be furnished in either the as-welded, sunk or
- Special Smooth ID - A cold drawn tube in which special
attention is paid to the internal surface. Depth of pits and scores
in ID are guaranteed to be below published maximum depths.
Microinch finish is guaranteed in ERW tubes.
The amount of permanent stretch, usually referring to a
measurement of a specimen after fracture in a tensile test. It is
expressed as a percentage of the original gage length.
- Endurance Limit
The maximum stress below which a material can presumably endure
an infinite number of stress cycles.
- Etch Test
Exposure of a specimen to acid attack for the purpose of
disclosing the presence of foreign matter, defects, segregation
pattern, or flow lines.
Production process in which steel is forced by compression
through a die into solids (round or special shape) or through a die
and over a mandrel to form a tubular shape.
- Fatigue Limit
Synonymous with Endurance Limit.
- Ferritic Stainless Steels
The designation used for certain high chromium content steels
that exhibit microstructures consisting mainly of ferrite at
ordinary temperatures. Ferritic stainless steels are divided into
two classifications: hardenable, and non-hardenable. When rapidly
cooled from elevated temperatures the non-hardenable grades
(ferritic) have a ferritic microstructure. The hardenable grades
(martensitic) will exhibit a martensitic micro-structure when
rapidly cooled. Ferritic and martensitic stainless steel alloys are
magnetic in all conditions.
In the steel industry, refers to the type of surface condition
desired or existing in the finished product.
- Finish Anneal
See heat treatment.
- Finish Machine Size
Normally specified in terms of the maximum machined OD and the
minimum machined ID as applied to tubular parts. Finish machine
size represents the size of the part as it comes from the final
machining operation. From this size the tube mill can calculate a
tube size which will be guaranteed to cleanup upon machining.
- Flame Hardening
A process of heating the surface layer of an iron-base alloy
above the transformation temperature range by means of the flame of
a high temperature torch, followed by quenching.
- Flanged End
In a flanged end the tube has been belied or expanded and a
flange turned over until the wall of the tube end is at right
angles to the wall of the tube.
- Flare Test
A test applied to tube, involving a tapered expansion over a
cone. Similar to a pin-expansion test.
- Flash-In Tubing
See Electric Resistance Welded Tubing.
- Flash Removed
See Electric Resistance Welded Tubing,
Used as a general term to describe the roiling, pressing or
hammering of steel which displaces the metal under compression by a
locally applied force, usually at hot working temperatures.
- Fracture Strength
As usually related to the tensile test, fracture strength or
true breaking strength is defined as the load on the specimen at
the time of fracture.
- Full Anneal
See heat treatment.
- Gages, Gauges
A measurement of thickness. There are various standard gages
such as United States Standard Gage (USS), Galvanized Sheet Gage
(GSG), Birmingham Wire Gage (BWG).
- Grain Size
A measure of the size of individual metallic crystals usually
expressed as an average. Grain size is reported as a number in
accordance with procedures described in ASTM grain size
The property in steel that determines the depth and distribution
of hardness induced by cooling from a suitable elevated
temperature. The hardness can vary with the cooling rate.
A measure of the degree of a materials resistance to
indentation. It is usually determined by measuring resistance to
penetration, by such tests as Brinell, Rockwell, and Vickers.
- Heat Exchanger Tube
A tube for use in apparatus in which fluid inside the tube will
be heated or cooled by fluid outside the tube. The term usually is
not applied to coiled tubes or to tubes for use in refrigerators or
- Heat Treatment
A combination of heating and cooling operations applied to a
metal or alloy in the solid state to obtain desired conditions or
properties. Heating for the sole purpose of hot working is excluded
from the meaning of this definition. See various types below.
- Age Hardening - Hardening by aging, usually after rapid cooling
or cold working. Hardening is a result of a precipitation process,
often submicroscopic, which occurs when a supersaturated solid
solution is naturally aged at atmospheric temperature or
artificially aged in some specific range of elevated temperature.
Aging occurs more rapidly at higher temperatures. (Synonymous with
- Air Hardening - Heating a suitable grade of steel with high
hardenability above the critical temperature range and then cooling
in air for the purpose of hardening.
- Annealing - Annealing is a heat treatment process that usually
involves a relatively slow cooling after holding the material for
some time at the annealing temperature. The purpose of the
annealing treatment may include the following: (a) to induce
softness; (b) to remove internal stresses; (c) to refine the grain
size; (d) to modify physical and or mechanical properties; (e) to
produce a definite microstructure; (f) to improve machinability. It
is generally desirable to use more specific terms in describing the
heat treatment to be used, e.g., finish anneal, full anneal or
medium anneal, as applicable
- Bright Anneal - Carried out in a controlled furnace atmosphere,
so that surface oxidation is reduced to a minimum and the tube
surface remains relatively bright.
- Dead Soft - A heat treatment applied to achieve maximum
softness and ductility.
- Drawing - Synonymous with Tempering, which is preferable.
- Finish Anneal - Heating of cold-worked tubing to a temperature
below the lower critical, usually 950 Degree. Generally this
treatment will relieve peak stresses without altering hardness to
- Full Anneal - Heating to a temperature above the upper critical
and slow cooling below the lower critical.
- Isothermal Anneal - Austenitizing a heat treatable alloy and
cooling to and holding at a temperature at which austenite
transforms to a relatively soft ferrite-carbide aggregate.
- Medium Anneal - Subjecting tubing to a subcritical temperature
to obtain specific mechanical properties.
- Normalize - Heating a ferrous metal to a temperature
approximately 100 Degree F. above the upper critical temperature
and cooling in still air.
- Quenching - A process of rapid cooling from an elevated
temperature, by contact with liquids or gases.
- Soft Anneal - A high temperature stress relieving anneal
usually performed in the temperature range of 1250 to 1350 Degree
F. This anneal reduces hardness and strength of a cold worked steel
to achieve near maximum softness.
- Solution Anneal - Heating steel into a temperature range
wherein certain elements or compounds dissolve, followed by cooling
at a rate sufficient to maintain these elements in solution at room
temperature. The expression is normally applied to stainless and
other special steels.
- Spheroidizing Anneal - A general term which refers to heat
treatments, that promote spheroidal or globular forms of carbide in
carbon or alloy steels.
- Stabilizing Anneal - A treatment applied to austenitic
stainless steels wherein carbides of various forms are deliberately
precipitated. Sufficient additional time is provided at the
elevated temperature to diffuse chromium into the areas adjacent to
the carbides (usually grain boundaries). This treatment is intended
to lessen the chance of intergranular corrosion.
- Stress Relieving - A heat treatment which reduces internal
residual stresses that have been induced in metals by casting,
quenching, welding, cold working, etc. The metal is soaked at a
suitable temperature for a sufficient time to allow readjustment of
stresses. The temperature of stress relieving is always below the
transformation range. Finish anneal, medium anneal and soft anneal
(sub-critical) describe specific types of stress relief
- Tempering - Reheating quenched or normalized steel to a
temperature below the transformation range (lower critical)
followed by any desired rate of cooling.
- Hot Finished Seamless Tubing
Tubing produced by rotary piercing, extrusion, and other hot
working processes without subsequent cold finishing operations.
- Hot Rolled ERW Tubing
As welded electric resistance welded tubing made from hot rolled
strip or sheet.
- Hot Shortness (Red Shortness)
A condition encountered in some metals wherein ductility is
lessened at hot working temperatures.
- Hot Working
The mechanical working of metal above the recrystallization
- Huey Test
A corrosion test for stainless steels. The weight loss per unit
area is measured after each of five 48-hour boils in 65 % nitric
acid (per ASTM A 262 Practice C). The test results are calculated
to and reported as the average corrosive rate of the five boils in
inches per month (1pm) corrosion rates. The test is used to
determine the suitability of a material for nitric acid service.
Since most of the weight loss is due to intergranular attack, the
Huey test is commonly used as an indication of the resistance of a
stainless steel to intergranular corrosion.
- Hydrostatic Test
A test in which a liquid, usually water, under pressure, is used
internally to detect and locate leaks in a tube of a fabricated
- Impact Testing
There are several methods of determining the toughness of a
steel, but the Izod and Charpy notched-bar tests are used quite
widely. In both tests, the samples are cooled or heated to the
desired test temperature, then struck once with a pendulum that
fractures the specimen. The energy required to fracture the
specimen, the impact strength, is measured in foot-pounds.
Particles of nonmetallic impurities, usually oxides, sulphides,
silicates, which are mechanically held in metals and alloys during
- Induction Heating
A process of heating by electrical induction.
A cast metal shape suitable for subsequent rolling or forging.
Ingot Mold - A mold in which ingots are cast. Molds may be
circular, square, or rectangular in shape, with walls of various
thickness. Some molds are of larger cross section at the bottom;
others are larger at the top.
- Integral Finned Tubing
Tubing with raised surface fins formed from the wall of the tube
- Intergranular 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.
- Internal Soundness
Refers to condition of inside of materiallack of defects, pipe,
segregation, non-uniformity of composition.
- Isothermal Anneal
See heat treatment.
- Izod Impact Test
See Impact Strength Testing.
- Jominy Test
Hardenability test performed usually on alloy steels to
determine depth and degree of hardness resulting from a standard
end quenching method with cold water.
- Killed Steel
Steel deoxidized with an agent such as silicon or aluminum to
reduce the free oxygen content so that no harmful reaction occurs
between carbon and oxygen during solidification.
A large vessel into which molten steel or molten slag is
received and handled.
- Ladle Analysis
Chemical analysis obtained from a sample taken during the
pouring of the steel.
Defects resulting from the presence of blisters, seams or
foreign inclusions aligned parallel to the worked surface of a
A surface defect caused from folding the surface of an ingot,
bloom or bar during hot rolling operations and then rolling or
forging the fold into the surface.
A measure of the relative ease with which steel may be machined.
Adding sulphur, phosphorous or selenium to a heat of steel can
improve the metals machinability.
The deliberate removal of metal by one or more of several
A testing procedure for locating and identifying 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 without a microscope.
- Magnaflux Test
This test is conducted by suitably magnetizing the material and
applying a prepared wet or dry magnetic powder or fluid which
adheres to it along lines of flux leakage. It shows the existence
of surface and slightly subsurface non-uniformities.
The property that determines the ease of deforming a metal when
the material is subjected to rolling or hammering. The more
malleable metals can be hammered or rolled into thin sheet more
easily than others.
(1) A device 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.
A process of improving the mechanical strength of certain
ferrous alloys. The name was derived from two hardening reactions:
martensite and aging. The maraging strengthening mechanism is based
on the age hardening (precipitation hardening) of extra-low carbon
A constituent in quenched steel formed without diffusion and
only during rapid cooling below the martensitic start (Ms)
temperature. Martensite is the hardest of the transformation
products of austenite.
- McQuaid-Ehn Test
A special test for revealing the austenitic grain size of
ferritic steels when the steel is heated to 1700 Degree F. and
carburized. There are eight standard McQuaid-Ehn grain sizessizes 5
to 8 are considered fine grain and sizes under 5 are considered
- Mechanical Properties
Those properties of a material that reveal the elastic and
in-elastic reaction when force is applied, or that involve the
relationship between stress and strain; for example, the modulus of
elasticity hardness, tensile strength and fatigue limit. These
properties have often been referred to as physical properties, but
the term mechanical properties is correct.
- Mechanical Tubing
Used for a variety of mechanical and structural purposes, as
opposed to pressure tubing, which is used to contain or conduct
fluids or gases under pressure. It is used for the starting stock
for machined or formed parts of industrial, automotive,
agricultural aircraft, transportation, material handling and
household equipment. It may be hot finished or cold drawn. It is
commonly manufactured to consumer specifications covering chemical
analysis and mechanical properties. It is made to exact OD and wall
thickness dimensions and custom produced to end-use applications in
seamless and welded condition.
The science dealing with the constitution, and structure of
metals and alloys as revealed by the unaided eye or by such tools
as low powered magnification, optical microscope, electron
microscope and diffraction or X-ray techniques.
Refers to the extent or quality of nonmetallic inclusions
observed by examination under a microscope.
Micro-etching is used for the examination of a sample under a
microscope. Etching solutions tend to reveal structural details
because of preferential chemical attack on the polished
- Minimum Wall
Any wall having tolerances specified all on the plus side.
- Modulus of Elasticity
The ratio of stress applied to a material and the resulting
strain occurring at the stresses below the elastic limit.
A process of case hardening in which a ferrous alloy, usually of
special composition, is heated in an atmosphere of cracked ammonia
or in contact with nitrogenous material to produce surface
hardening without quenching by the absorption of nitrogen.
Nitriding is normally conducted in a range from 900 to 1000 degrees
- Non-Destructive Testing
Methods of detecting defects without destroying or permanently
changing the material being tested. Test methods include
ultrasonic, eddy current, magnetic particle, liquid, penetrant, and
- Notch Brittleness
Susceptibility of a material to brittle fracture at points of
- Notch Sensitivity
A measure of the reduction in strength of a metal caused by the
presence of stress concentration.
- Open Hearth Furnace
A reverberatory melting furnace with a shallow hearth and a low
roof. The flame passes over the charge in the hearth, causing the
charge to be heated both by direct flame and radiation from the
roof and sidewalls of the furnace.
The difference between the maximum and minimum outside diameters
of any one cross section of a tube. It is a measure of deviation
In its simplest terms, oxidation means the combination of any
substance with oxygen. Scale developed during heat treatment is a
form of oxidation.
A compound consisting of oxygen and one or more metallic
The changing of the chemically active surface of a metal to a
much less active state by the application of the proper chemical
treatment or by applying an induced electrical current and voltage
for cathodic or anodic protection from corrosion. An example of
chemically passivating stainless steel would be to immerse
stainless in a hot solution of approximately 10 to 20 per cent by
volume nitric acid and water.
A photographic reproduction of an object magnified more than ten
times used to show microstructure characteristics of steel.
- Physical Properties
Those properties not specifically related to reaction to
external forces. These include such properties as density,
electrical resistance, coefficient of thermal conductivity.
Use of solutions, usually acids, to remove surface oxides from a
tube, may also be used to produce a desired surface finish.
A seamless tubemaking method in which a hot billet is gripped
and rotated by rolls or cones and directed over a piercer point
which is held on the end of a mandrel bar.
A sharp, usually small, depression in the surface of metal.
Pitting is forming small sharp cavities in a metal surface by
nonuniform electro-deposition or by corrosion.
Unsoundness caused in cast metals by the presence of blowholes
or shrinkage cavities.
- Pressure Tubing
Tubing produced for the purpose of containing or conducting
fluids or gases under pressure. It is produced to exact diameters
and decimal wall thicknesses to ASTM or ASME specifications for
boiler, heat exchanger, condenser tubes, etc. Made by both seamless
and welded processes in carbon, alloy, and stainless steels.
An instrument used for measuring surface finish. The vertical
movements of a stylus as it traverses the surface are amplified
electromagnetically and recorded (or indicated) as the surface
- Proof Stress
The load per square inch of the original cross-sectional area
which, when removed, has caused a permanent elongation not
exceeding a defined amount (usually 0.0001 per inch of gage
length). A test of this type is more commonly used in Europe than
in this country, where it largely has been replaced by yield
An instrument of any of various types used for measuring
- Quench Cracking
Cracking resulting from stresses produced during the austenite
to martensite transformation during heat treating (quench and
tempering). Any condition that concentrates the stresses
encountered in quenching will promote the formation of quench
cracks (e.g. corners, hoves, or keyways; too fast a quench medium;
excessive time delay from quench to temper).
- Quench Hardening
Hardening a ferrous alloy by austenitizing and then cooling
rapidly enough so that some or all of the austenite transforms to
See heat treatment.
The reversion of distorted cold worked microstructure to a new,
strain-free structure during annealing.
- Reduction of Area
A measure of ductility determined in a tensile test. It is the
maximum reduction, at the fracture, of the cross section area of a
specimen, as compared with its original cross section area.
- Residual Stress
Stress present in a body that is free of external forces or
- Rimmed Steel
A steel that forms a relatively clean outer layer (rim) during
solidification. Sheet and strip made from such steel has good
surface quality and is frequently used for ERW tubing.
- Rockwell Hardness
- Roto-Rock (Tube Reducing or Rockrite)
A method of cold finishing tubing in which a machine rolls or
rocks a split die over a tube. The tube is supported on the inside
by a tapered mandrel.
An oxide of iron that forms on the surface of hot steel.
A tight, but unwelded imperfection on the surface of a wrought
Non-uniform distribution of alloying elements, impurities or
- Semi-Killed Steel
Steel that is incompletely deoxidized to permit the evolution of
carbon monoxide, thereby offsetting solidification shrinkage.
Sensitization of stainless steel is defined as a susceptibility
to preferential grain boundary attack. Material that exhibits grain
boundary carbide precipitation may or may not be sensitized.
To hold an ingot, slab, bloom, billet or other piece of steel in
a hot furnace, pit or chamber to secure uniform temperature.
- Soaking Pit
A furnace or pit for the heating of ingots of steel to make
their temperature uniform prior to rolling or forging.
- Soft Anneal
See heat treatment.
- Spark Test
is a method of determining the
materials. It normally entails taking a piece of metal,
usually scrap, and applying it to a grinding wheel in
order to observe the sparks emitted.
- Special Smooth I.D. (SSID)
See Electric Resistance Welding Tubing.
A document defining the measurements, tests, and other
requirements to which a product must conformtypically covering
chemistry, mechanical properties, tolerances, finish, reports,
marking and packaging.
- Spheroidize Anneal
See heat treatment.
A type of forming (hot or cold) which involves rotating a tube
at high speed against fixed or rolling tools for the purpose of
altering shape, size, etc.
- Stabilizing Anneal
See heat treatment.
- Stainless Steel
Steel containing 10.5% or more chromium. Invented in 1903,
metallurgists discovered that adding chromium to carbon steels
imparted much improved corrosion resistance. Other major alloying
elements include nickel, manganese, molybdenum, silicon and
- Stress Corrosion Cracking
Cracking of metals under combined action of temperature,
corrosion and stress. The stress can be either applied or residual.
Austenitic stainless steels are especially susceptible to cracking
in chloride containing environments.
- Stress Relief Anneal
See heat treatment.
- Stretch Straightening
A process for straightening rod, tube, and shapes by the
application of tension at the ends of the stock.
A flat-rolled steel product that serves as the raw material for
- Sunk or Sink Drawn
Tubing drawn through a die with no inside mandrel to control
I.D. or wall thickness.
A mechanical reduction of the cross sectional area of a metal,
performed hot or cold by forging, pressing or hammering.
The act of pouring molten metal from a furnace into a ladle.
Act of pouring molten metal from a ladle into an ingot mold.
See heat treatment.
- Tensile Strength
The maximum load per square inch of original cross-sectional
area carried during a tension test to failure of the specimen. This
term is preferred over the formerly used ultimate strength.
- Thermal Conductivity
A measure of the ease with which heat is transmitted through a
- Tungsten Inert Gas Welding TIG
welding process used for stainless steel and stainless
A twisting action resulting in shear stresses and strains.
A measure of ability to absorb energy and deform plastically
- Transformation Temperature
The temperature at which a change in phase occurs in steels. The
term is sometimes used to denote the limiting temperature of a
- Transverse Tension Test
A tension test for evaluating mechanical properties of a
material in a direction transverse to that of rolling.
A method for removing the surface from a work piece by bringing
the cutting edge of a tool against it while the piece or tool is
- Ultimate Strength
See tensile strength.
- Ultrasonic Testing
The method of detecting defects in tubes or welds by passing
high frequency sound waves into a material then monitoring and
evaluating the reflected signals.
A metalworking operation similar to forging, generally used to
thicken the ends of tubes prior to threading.
- Vickers Hardness Test
- Work Hardening
Hardness developed in metal as a result of cold working. See
- Yield Point
The first stress in a material measured as load per unit of
original cross-sectional area at which an increase in strain occurs
without an increase in stress.
- Yield Strength
The stress at which a material exhibits a specified deviation
from proportionality of stress and strain. An offset of 0.2 is most