1.1 this specification covers thermoforming welding and seamless carbon steel square, circular, rectangular or special shaped structure tubes for bridge and building welding, riveting or bolt connection and general structural use.
1.2 square and rectangular pipes are from 1 to 10 inches (25.4 to 254 millimeters), and the plane wall thickness is 0.095 to 1000 inches (2.41 to 25.40 mm), depending on the size. The circular pipe is provided, including the nominal (average) wall thickness of 0.109 to 1 inches (2.77 to 25.40 milli meters), and the size depends on the size. As long as this pipe meets all other requirements of this specification, it can provide other sizes of pipes.
1.3 pipes can be equipped with hot dip galvanized coating.
1.4 the value expressed in inch pound units should be used as a standard.
Note in this standard, the dimensionless indicator NPS (nominal diameter) has been replaced by the traditional term "nominal diameter", "size" and "nominal size".
| Grade | Yield (min) | Tensile (min) | Elongation (min) |
| Grade A | 39,000 psi | 45,000 psi | Determined by wall |
| Grade B | 46,000 psi | 58,000 psi | Determined by wall |
| Grade C | 50,000 psi | 62,000 psi | Determined by wall |
Below are physical properties required to meet the three grades that we produce ASTM A501 round tubing to. A flattening test is also a standard requirement for round tubing produced to the A501 specification.
| Grade | Yield (min) | Tensile (min) | Elongation (min) |
| Grade A | 33,000 psi | 45,000 psi | Determined by wall |
| Grade B | 42,000 psi | 58,000 psi | Determined by wall |
| Grade C | 46,000 psi | 62,000 psi | Determined by wall |
