Dimensional tolerance of ERW steel pipe

For standard pipe, except as provided for thin-wall pipe, the tolerances of diameter shall be in accordance with the following table:

Tolerance of outside diameter
 Out Diameter  Tolerance of Pipe End  Tolerance of Pipe Body
 219.1-273.1  +1.6mm, -0.4mm   ±0.75% 
 274.0-320  +2.4mm, -0.8mm  ±0.75% 
 323.9-457  +2.4mm, -0.8mm  ±0.75% 
 508  +2.4mm, -0.8mm  ±0.75% 
 559-610  +2.4mm, -0.8mm  ±0.75% 
Tolerance of wall thickness
 Grade  Out Diameter  Wall Thickness
 /  219.1-457  +15%, -12.5%
 B  508-610  +17.5%, -12.5% 
 X42-X80  508-610  +19.5%, -8%

Weled steel pipe specification, Standard and identification

Welded steel pipe (steel pipe manufactured with a weld) is a tubular product made out of flat plates, known as skelp, that are formed, bent and prepared for welding.