American Petroleum Institute – issues standards for all industry

American Society for Testing Materials – issues standards for line pipe

ASTM grades of carbon steel pipe

Denotes lacquered OD finish (as opposed to bare or galvanized)

Hardness testing system which measures indentation of the surface using a standard weight, shaped point

Internal pressure at which a tube will yield – often tested hydrostatically

Pipe or tubing which is pulled through a die to reduce diameter and wall.  This process usually produces close tolerances and higher strength.

Minimum ID clearance verified by pulling a mandrel size through a length of pipe

Electromagnetic inspection – a method of determining thickness and detecting imperfections in steel tubes.

Electric resistance weld–most common form of mandrel for pipe in sizes from 2 3/8–22” OD

Inside diameter

Pipe size or wall thickness as specified (not actual) refer to approximate ID, even though OD is the fixed dimension

Outside diameter

Relative resistance of a metal to indenation by a dimond expressed in hardness scale units (A, B, C or G)

Submerged are weld – a method of producing very large pipe

Colled strips of plate steel used to produce welded

Rating of steel’s resistance to being pulled apart.

Specified allowance (plus or minus) of the given dimension finished product due to inaccuracies in manufacturing; usually small (thousands of an inch or very small percentage) an part of a standard such as ASTM or API.

Tensile stress required to produce permanent elongation of a steel tube.