ASTM A618 Structural Steel Pipe and Tubing


ASTM A618 pipe is a welded and seamless structural pipe made from high-strength low-alloy steel. It is produced in various diameter sizes with standard schedule wall thicknesses. Both black and galvanized surface finishes are available. View the specification table

Material Composition

ASTM A618 Chemical Requirements
Composition,   %Grade IaGrade IbGrade IIGrade III
Carbon, max0.150.180.2. . .
Manganese1.00 max1.04 max1.35 max1.40 max0.85–1.251.30 max1.35 maxA1.40 maxA
Phosphorus,   max0.150.160.0250.0350.0250.0350.0250.035
Sulfur, max0.0250.0450.0250.0350.0250.0350.0250.035
Silicon, max. . .. . .. . .. . .0.30.330.30.35
Copper, min0.20.180.20B0.18B0.20.18. . .. . .
Vanadium, min. . .. . .. . .. . .
Chemical Composition Table

Manufacturing Process

Seamless pipe is hot extruded while welded pipe uses high heat input welding techniques and 100% radiography to test joint quality. Proper welding procedures as per ASTM standards ensure joint strength.

Mechanical Properties

ASTM A618 Tensile Requirements
 Grades la, lb, and llGrade lll
 Walls 3⁄4  in.Walls over 3⁄4 to 11⁄2    in. 
 [19.0 mm][19.0 to 38.0mm], incl 
 and Under  
Tensile strength, min, ksi [MPa]A70[485]67[460]65[450]
Yield strength, min, ksi [MPa]A50[345]46[315]50[345]
Elongation in 2 in. or 50 mm, min, %22 22 20 
Elongation in 8 in. or 200 mm, min, %19 18 18
ASTM A618 Structural Steel Pipe and Tubing
ASTM A618 Structural Steel Pipe and Tubing


Common applications include structural supports, pilings, hand rails, sign posts where high strength is required. It is also used in power generation, construction and infrastructure projects due to strength, corrosion resistance and cost-effectiveness.


Higher strength-to-weight ratio allows smaller sizes and foundations. Resistance to weathering and corrosion improves durability. Forming and joining are easy due to consistent mechanical properties. Mill test reports certify quality.

Inspection and Testing

All pipes undergo hydrostatic and flattening tests as per ASTM A618. Mill test reports include chemical analysis, pressure test results and dimensional checks according per order requirements.

Additional Information

For queries related to technical data, application suitability, scheduling or procurement, please contact us. Our team of experts can assist and provide quotations for ASTM A618 structural pipe as per your requirements.

Quick Contact

Mail Me


+86 153 1871 5360

If any steel product meet your demand, please share with me material grade or other requirement.