Alloy Steel
Steel is commercially classified as alloy when it contains alloying elements of at least: 1.65% manganese; 0.60% copper; and 0.60% silicon.

Alloying Elements
Chemical elements, such as nickel, chromium, copper or others, added to improve properties of a finished product.

Heat treatment that alters the microstructure of a material, changing properties such as strength, hardness or ductility.

American Petroleum Institute – Corpac provides high-quality tubing designed to withstand the rigors of transporting oil and gas from the production zone to the surface.

American National Standards Institute. Formerly the ASA American Standards Association.

American Society of Mechanical Engineers

American Society for Testing Materials – ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards.

American Water Works Association


Barlow’s Formula
Equation showing the relationship of internal pressure to allowable stress, nominal thickness and diameter (P=2St/D).

Bend Test – Various tests used to determine ductility of sheet, plate or tubulars subjected to bending.

Bevel – Angle between prepared edge of the end of a pipe and the plane perpendicular to the surface of the member. Standard bevel for line pipe is 30 degrees to facilitate welding.

Billet – Solid, semi-finished round or square product that has been either directly cast from a strand caster or hot-worked by forging, rolling or extrusion.

Black – Term associated with pipe surface. Material ordered “black” is protected with varnish-type oil on the OD for temporary corrosion protection during transit and storage.

Black Bare – Term associated with pipe surface, in which pipe is not coated with mill spray oil; grease spots and cutting oil are removed by washing.

BOP or BOF – Basic oxygen process or basic oxygen furnace.

Burst Test – Destructive hydraulic test used to determine actual yield strength and ultimate strength of both seamless and welded pipe.

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Carbon Steel – Metal alloy formed by a combination of iron and carbon, where other elements are present in quantities too small to affect the properties. The only other alloying elements allowed in plain-carbon steel are: manganese (1.65% max), silicon (0.60% max), and copper (0.60% max). Steel with low carbon content has the same properties as iron – soft, but easily formed. As carbon content rises, the metal becomes harder and stronger but less ductile and more difficult to weld. Higher carbon content lowers steel’s melting point and its temperature resistance in general.

CE – Carbon Equivalent

Charpy Test – Method for measuring the amount of energy absorbed by a notched specimen during fracture as a result of an impact load.

Check Analysis – Chemical analysis of a metal after it has been rolled or forged into a semi-finished or finished form.

Chemical Properties – Minimum or maximum limits, normally associated with a limited number of chemical elements, are established in most ASTM and API specifications.

Coating – Process of covering steel with another material, primarily for corrosion resistance.

Columbium – Alloying element added to high-strength, low-alloy steels, which increases strength and retards grain growth and recrystallization during controlled rolling.

Conduit – Pipe serving as a duct for electrical wiring.

Continuous Casting – Process of pouring and solidification of steel heats in a continuous strand.

Coupling – Threaded sleeve used to connect two lengths of pipe.

Continuous Weld – Commonly used phrase for continuous butt weld. Furnace-welded pipe produced in continuous lengths from coiled skelp and subsequently cut into individual lengths, having its longitudinal butt joint forge welded by the chemical pressure developed in rolling the hot-formed skelp through a series of round-pass welding joints.

Crack, Hook – Metal separations resulting from imperfections at the edge of the plate or skelp, parallel to the surface, which turn toward the ID or OD surfaces when the edges are upset during welding.

Cut Length – Pipe cut to specific length as ordered.

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DN – Diameter Nominal – a dimensionless designator for traditional terms such as “nominal diameter,” “size,” and “nominal size”.

Double Extra Strong – Standard pipe weight designation (XXS), sometimes described as XXH (double extra heavy).

Double Jointed – Two standard-length pipe joints welded together to form a single joint or double length.

Dry – Term associated with pipe surface in which the pipe is not coated with a corrosion inhibitor and all grease spots and cutting oil are removed by washing.

DRL – Double Random Length (35′ minimum average or as defined in specifications)

Drop Weight Tear Test – Impact test used to determine the nil ductility transition temperature of ferric steel.

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Eddy Current Testing – Nondestructive testing method in which eddy current flow is included in the test object. Changes in flow caused by the specimen are reflected into a nearby coil/s for subsequent analysis by suitable instrumentation and techniques.

Elongation – In ensile testing, the increase in gage length measured after fracture of a specimen within the gage length, usually expressed as a percentage of the original gage length.

ERW – Electric Resistance Weld (see high-frequency welding).

Expanders – Mechanical device used to expand pipe to obtain increased transverse yield strength and the desired OD size.

Extra Strong – Standard pipe designation (XS), sometimes described as XH (extra heavy)

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Flattening Test – A quality test for tubing, where flattened between parallel plates closed to a specific height.

Fracture test – Breaking a piece of metal for purposes of examining the fractured surface to determine the structure or carbon content of the metal, or to detect the presence of internal defects.

Full Body Normalizing – Uniformly heating pipe to a temperature above the point at which grain structure is affected, followed by cooling in the still air. Produces uniform grain structure and hardness throughout the pipe.

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Galvanizing – Covering an iron or steel surface with a protective layer of zinc.

Grade – Designates divisions within different types based on carbon contents or mechanical properties; for example, “high-tensile grade structural steel”

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Hardenability – Property that determines the depth to which the steel will harden.

Hardness – Defined in terms of the method of measurement, usually (1) the resistance to indentation; (2) stiffness of temper of wrought products; and (3) machinability characteristics.

Heat – (1) Form of energy that raises the temperature of bodies into which it is absorbed; or (2) an individual bath of metals as it is melted in a furnace.

Heat Analysis – Term applied to the chemical analysis representative of a heat of steel, determined by analyzing a test sample obtained during the pouring of the steel from a ladle.

Heat Treatment – A combination of heating and cooling operations applied to a metal or alloy in its solid state to obtain desired conditions or properties.

HIC Test – (Hydrogen-Induced Cracking) is used to evaluate the resistance of pipeline and pressure-vessel plate steels to cracking caused by hydrogen absorption from aqueous sulfide corrosion. An unstressed test specimen is exposed to a solution at ambient temperature and pressure; after a specified time, the test specimen is removed and evaluated.

High Frequency Welding – Technique employed in manufacturing of electric resistance weld pipe. Typical radiofrequency power for welding is supplied at 450,000 cycles/sec.

High Strength Steel – Low alloy steels with moderate proportions of one or more alloying elements other than carbon that form a specific class with enhanced mechanical properties and, in most cases, good resistance to atmospheric corrosion. Preferred term is “High-strength low-alloy steels.”

Hydrostatic Test – Normal mill test whereby pipe ends are sealed and high-pressure water is introduced to predetermined pressures as required by specifications.

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ID – Inside diameter

Impact Test – A test to determine the energy absorbed in fracturing a test bar at high velocity. The test may be in tension or it may properly be a notch test is present, creating multiaxial stresses.

Inclusions – Non-metallic solid material entrapped in the weld deposit or between weld metal and base metal. Results from products of oxidation, material erosion or entrainment during the steel-making process.

ISO – International Organization for Standardization – ISO 9001:2008 certification is granted to organizations that adhere to international standards for quality management that ensure the organization fulfills and achieves continual improvement of its performance in pursuit of the customers’ requirements, applicable regulatory requirements and enhancement of customer satisfaction.

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Ladle – Large vessel into which molten metal or molten slag is received and handled or carried for short distances.

Ladle Analysis – Term applied to the chemical analysis reported to the purchaser, representative of a heat or blow of steel. Determined by analyzing a test ingot sample obtained from the first part or middle part of the heat or blow during the pouring of steel from a ladle.

Land – Face at pipe and between the bevel and the interior surface.

Lifts – Term associated with separated segments of pipe (banded or unbanned for ease of handling)

Line Pipe – Line pipe is generally manufactured for the conveyance of oil and gas in transmission lines, distribution main lines, and offshore pipeline systems.

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Magnaflux Test – Inspection given to important or highly stressed parts of pipe for critical applications. Consists of suitably magnetizing the material and applying a prepared magnetic powder which adheres to it along lines of flux leakage, showing the existence of surfaces, non-uniformities and electromagnetic current.

Magnetic Particle Inspection – Nondestructive testing method utilizing iron powder and electromagnetic current to detect cracks and other discontinuities at or near the surface in ferromagnetic materials.

MAOP– Maximum Allowable Operations Pressure

Mechanical Properties – Properties that describe how an object performs when a load or stress is applied to it. For example, stainless steel is classified as steel having a composition of at least 10% chromium, and further classified into magnetic and non-magnetic types, each with its own mechanical properties.

Metallurgy – Science pertaining to the extraction of metals from their ores and the adaption and application of these metals.

Mill Finish – Surface finish produced on sheet and plate, with characteristics of the ground finish on rolls used to fabrication.

Molybdenum – Hard substance used to alloy many specialty steels, it is softer and more ductile than tungsten. Molybdenum has a high elastic modulus, and only tungsten and tantalum have higher melting points. Other common uses for molybdenum are electrodes, furnace applications, nuclear energy and missile and aircraft parts.

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NDE – Nondestructive examination, or the utilization of nondestructive testing methods, primarily eddy current, liquid penetrant, magnetic particle, radiography and ultrasonic.

Nominal – Name given to standard pipe size designation.

Normalize – Process commonly applied to steel articles of heavy section consisting of heating to a temperature of 100 degrees F.

NPS – Nominal Pipe Size

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OCTG Pipe – Oil Country Tubular Goods – OCTG stands for Oil Country Tubular Goods, and includes pipe and steel tubing products used in petroleum industry, such as drill pipe, pipe casings, oil pipes.

OD – Outside Diameter

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PE – Plain End

PESC– Plain End Square Cut

Pickling – Pipe immersed into acid bath for removal of scale, oil, dirt, etc.

Piling – One of a group of piles made of timber, steel, or pre-stressed concrete set close together to resist lateral pressure, such as from earth or water.

Plate – Carbon steel plate or flat rolled finish steel products within a size limitation.

Product Analysis – Chemical analysis of the pipe.

Preheating – General term used to describe heating applied as preliminary to further thermal or mechanical treatment.

PSI – Pounds per Square Inch

PSIG – Pounds per Square Inch Gage

PSL – Product Specification Level

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QS– Quad Stencil

Quenching – Process of rapid-cooling from an elevated temperature by contact with liquids, gasses or solids.

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Random Lengths – Lengths that can be specified, but, if random lengths are permitted, cutters have a spread from 2 to 5 feet, depending on ordered length and size.

RDS – Rounds. For seamless tubular products, the round is heated and pierced to form a tube hollow.

Regular Mill Coat – Term associated with pipe surface whereby the pipe is coated with a corrosion inhibitor.

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SC– Square Cut

Scale – An oxide of iron that forms on the surface of hot steel.

Scarfing – Process of cutting surface areas of metal objects, typically using a gas torch. Permits surface defects to be cut from ingots, billets or the edges of plates that are to be beveled.

Schedule Numbers – ANSI numbers assigned to pipe depending upon wall thickness.

Seam Annealed – Heating a weld seam to a temperature slightly below the point at which grain structure is affected, thereby reducing weld hardness without changing the grain structure.

Skelp – 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.

Slab – Semi-finished block of steel cut from a rolled ingot.

SMLS – Seamless

SMTS– Specified Minimum Tensile Strength

SMYS– Specified Minimum Yield Strength

SRL – Single Random Lengths

Steel – General name given to a range of iron alloys. The three major types of steel are: carbon, alloy and stainless.

Stencil – Sprayed paint identification placed on a pipe.

STD – Standard

Straightening – Removal of sweep and camber by roller straightening or use of a gag press.

Stress – Load per unit of area. Typically, stress-strain curves do not show the true stress (load divided by area shows this).

Stress Relieving – Process of reducing residual stresses in a metal object by heating the object to a suitable temperature and holding it for a sufficient time, then cooling it slowly.

Stretch Reduction – Property of absorbing considerable energy before fracture; usually represented by the area under stress-strain curve, involving both ductility and strength.

Structural Steel – Structural steel is strong steel that is rolled into shapes that are used in construction.

Surface Inspection – Inspection of the surface of products for defects such as: seams, burned steel, scabs, laps, twist, guide marks, etc.

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TBE – Threaded Both Ends

T&C – Threaded and Coupled

Tensile Strength – Value obtained by dividing the maximum load observed during tensile straining until breakage occurs, by the specimen cross-sectional area prior to straining.

Toughness – Property of absorbing considerable energy before fracture.

TS – Triple Stencil

Tubing – Corpac’s line of Energy Tubulars includes carbon and alloy products for the energy industry for the upstream, midstream and downstream operations.

Turn – Work shift in the mill, usually 8 hours long.

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Ultrasonic (UT) – Nondestructive testing method of detecting, locating, and measuring both surface and subsurface defects in metals using high-frequency sound.

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Wall-Heavy – Wall thickness greater than the specified minimum wall thickness called for in the pipe standard.

Wall Thin – Wall thickness less than the specified minimum wall thickness called for in the pipe standard.

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XS – Extra Strong, standard pipe weight designation. Sometimes called XH (extra heavy).

XXS – Double Extra Strong, standard pipe weight designation. Sometimes referred to as XXH (double extra heavy).

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Yield Point – In mild or medium-carbon steel, the stress point at which a marked increase in deformation occurs without increase in load. This phenomenon is not observed in other steels or in nonferrous metals.

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