Glossary of Terms

Not Sure What Something Means?  Check Out Our Glossary Of Terms For More Information.

Metals can be confusing and the industry loves to use abbreviations.  If you’re trying to “decode” what a vendor or customer means give our glossary of terms a shot.

ANNEALING
The process of heating and cooling a metal to achieve a reduction in hardness, remove stress, and to homogenize material.

AISI STEELS
Steels of the American Iron and Steel Institute. Common and alloy steels have been numbered in a system essentially the same as the SAE.

ASME (American Society of Mechanical Engineers)
An organization of engineers dedicated to the preparation of design code requirements, and material and testing standards. Adopts, sometimes with minor changes, specifications prepared by ASTM. The adopted specifications are those approved for use under the ASME Boiler and Pressure Code and are published by ASME in Section II of the ASME Code.

ASTM (American Society for Testing and Materials)
A body of industry professionals involved in writing universally accepted steel material and test specifications and standards.

AUSTENITIC
These grades of stainless steels (300 Series plus some 200) have chromium (roughly 18% to 30%) and nickel (roughly 6% to 20%) as their major alloying additions. They have excellent ductility and formability, at all temperatures, excellent corrosion resistance and good weldability. In the annealed condition they are nonmagnetic. These grades are usually non-magnetic and are used for applications requiring good general corrosion resistance such as food processing, chemical processing, kitchen utensils, pots and pans, brewery tanks, sinks, wheel covers and hypodermic needles.

BILLET
A solid semi-finished round or square product that has been hot worked by forging, rolling, or extrusion.

BRIGHT ANNEALING
A heat treat process performed in a carefully controlled furnace atmosphere resulting in a clean, smooth, scale free metal surface. During typical annealing, the heated steel combines with oxygen in the air to form an oxide layer on the steels surface. In bright annealing, the steel is heated in a furnace filled with gases, such as hydrogen or nitrogen, or in a vacuum, to prevent oxide scale formation.

BURST PRESSURE
The internal pressure that will cause a piece of tubing to fail by exceeding the plastic limit and tensile strength of the material from which the tube is fabricated.

CENTRIFUGAL CASTING
A casting made by pouring metal into a mold that is rotated or revolved.

CONCENTRICITY
Used to describe tubing where the center of its inside diameter is consistent with the center of its outside diameter resulting in no variation of wall thickness. 

DEBURRING
A method whereby the raw slit edge of metal is removed by rolling or filing.

DUPLEX STAINLESS STEELS
Stainless Steels exhibiting both austenitic and ferritic characteristics

EDDY CURRENT TESTING
A nondestructive testing procedure which is a continuous process performed on the tubular products during fabrication and in final inspection. It is by nature an electrical test that utilizes fluctuations in magnetic field strength to check tubing for possible defects.

ELECTROPOLISHING
An electro-chemical method of surface finish enhancement in which the metal to be polished is exposed to a suitable electrolyte, typically an acid solution, while carefully controlled current is passed between the object and a cathode.

HYDROSTATIC TESTING
A nondestructive test procedure that checks for holes, cracks or porosity. Tubing is pressurized internally with water to a high pressure, but does not exceed material yield strength.

ID
Inside diameter of a tubular or pipe product

INTERGRANULAR CORROSION
Corrosion that occurs at the grain boundaries in austenitic stainless steels that have been heated to and held at temperatures between 850° F and 1450° F. 

OD
Outside diameter of a tubular product.

OVALITY
A quantitative measurement of how ‘round’ a tube is by comparing width to height. Limits are specified by the specification of a product.

PASSIVATION
A protective layer of oxides on the surface of a metal, which resists corrosion. This passive oxide layer is the chief reason why stainless steels have such good corrosion resistant properties.

SCHEDULE, PIPE
A means of indicating the wall thickness of pipe sizes, as set forth in ASME B36.1 and ASTM A530 and B775. Commonly available pipe schedules are Schedules 5, 10, 20, 40, and 80. The actual wall thickness of a schedule number varies with the nominal pipe size or diameter (e.g.: 0.5″ Sch 40 = 0.109″ while 2″ Sch 40 = 0.154″). A higher number schedule indicates a thicker wall for a particular pipe diameter.

SEAMLESS TUBING
Tubular product that is made by piercing or hot extrusion to form the tube hollows. Further reduction of the tube hollows is accomplished by cold drawing or tube reducing to the final finish and size.

TENSILE STRENGTH
The maximum load per unit area that a material is capable of withstanding before it fails (pulls apart). Units are in psi.

ULTRASONIC TESTING
The scanning of material with an ultrasonic beam, during which reflections from faults in the material can be detected.

YIELD STRENGTH
The load per unit area that a material can withstand before permanent deformation (nonelastic) occurs.