Steel Tube and Pipe Glossary of Terms

Steel Tube and Pipe Glossary of Terms

 Steel tube term Description / meaning


This term describes the wall thickness of the steel tubes or pipes.



Hardness means resistance of the tube to deformation, usually measured in Rockwell or Vickers.

Heat Exchanger Tube

Tube used in applications where a fluid is passed through the tube and heated or cooled by fluid outside of the tube. The tube may be used in straigh lengths or "U" bends.


Heat Treatment

A process which involves heating and cooling through such as a furnace, to give enhanced ductility and surface finish.


Internal diameter of the steel tube or pipe.

Mechanical Properties

Consist usually of Yield, Tensile and Elongation values, and are dependant upon whether the tube is in the cold worked or heat treated condition.

Mechanical Tubing

Tube used for general purposes and maybe supplied cold drawn or heat treated dependant upon the application.


Refers to the heat treatment process carried out at a higher temperature than annealing.


Refers to the outside diameter of the steel tube.


The variation between maximum and minimum diameter giving a deviation from roundness.

Seamless steel tube/pipe

A hollow manufactured by piercing a billet and "stretching" to form a tube.


Wall thickness of the steel tube or pipe.

Welded steel tube/pipe

Tube or pipe manufactured from flat strip bent through a weld mill to form a tube and welded by using electrical resistance to heat up the strip edges prior to them being "pushed" together. The presence of the weld maybe visible.