ASTM A501 Grade B Carbon Steel Structural Tubing

Jun 16, 2025

ASTM A501 Grade B is a hot-formed welded and seamless carbon steel pipe with a minimum tensile strength of 448 MPa (65,000 psi) suitable for a variety of structural applications.

ASTM A501 applies to the manufacture and performance of hot-formed welded and seamless carbon steel pipe for structural applications.
These steel pipes can be black (uncoated) or hot-dip galvanized, the latter of which has improved corrosion resistance through the galvanizing process, making it suitable for a variety of environmental conditions.
These steel pipes are widely used in bridges, buildings, and many other general structural applications.

ASTM A501 standard specification covers black and hot-dip galvanized carbon steel pipe, including square, round, rectangular, and special shapes, for welded, riveted, or bolted structures, commonly used in bridges, buildings, and general structural applications. Products include welded and seamless pipes for a variety of structural uses.

The pipes should be manufactured by seamless, furnace butt welding (continuous welding), electric resistance welding, or submerged arc welding processes.

Square and rectangular tubes are available in flat sizes from 1 to 16 inches (25 to 405 mm) with wall thicknesses from 0.095 to 1.0 inches (2.5 to 25 mm). Round tubes are available in diameters from 1 to 48 inches (25 to 1220 mm) with wall thicknesses from 0.095 to 4.00 inches (2.5 to 1220 mm).

ASTM A501 Steel Grade Classification
ASTM A501 classifies steel tubes into three grades: Grade A, Grade B, and Grade C.

Grade B is the most widely used of the three grades because it provides balanced properties for a wide range of structural applications.

Raw Materials

Steel should be produced using either the basic oxygen furnace or electric arc furnace steelmaking process.

Steel may be cast in ingots or continuously cast.

When different grades of steel are cast sequentially, the steel producer shall identify the transition material produced and remove it using established procedures to clearly distinguish the different grades.

ASTM A501 Manufacturing Process
The pipe shall be manufactured by one of the following processes: seamless; furnace butt welding (continuous welding); electric resistance welding (ERW) or submerged arc welding (SAW), and then reheated across the cross section and hot formed by reducing or shaping processes (or both).

The SAW welding process is subdivided into straight seam submerged arc welding (LSAW) and spiral submerged arc welding (HSAW).

The final shape shall be formed by hot forming processes.

Grade: B

Shape: Square, round, rectangular or special shape

Length: 25 to 800 mm

Outer diameter: 0.4-0.7 mm

Wall thickness: 2.5 to 75 mm (square and rectangular tubes), 2.8 to 25.4 mm (round tube wall thickness)

Coating: Hot-dip galvanized or other coatings as required.

Charpy V-notch impact test: Wall thickness greater than 8 mm (0.312 inches) is applicable to B grade.

Process:

Seamless;

Furnace butt welding (continuous welding);