ASTM A618 Steel Pipe

What is ASTM A618 steel pipe?

ASTM A618 steel pipe is a welded and seamless pipe produced from high strength low alloy (HSLA) steel. It offers enhanced mechanical properties over carbon steel for demanding service conditions.

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 A618 pipe is hot extruded while welded pipe joints are fusion welded using high heat input processes. Proper welding procedure and non-destructive testing ensures quality of welds meeting ASTM standards.

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
Mechanical Properties Table


A618 pipe finds applications in refineries, chemical plants and power generation industries for transportation of high pressure steam, hot/cold fluids and slurries due to its high yield strength, tensile strength and corrosion resistance.

Schedules and Sizes

It is available in various pipe schedules as per ASTM A106 with standard dimensions ranging from 1/2″ to 60″. The wall thickness varies as per different pressure ratings.View the specification table

Benefits over Carbon Steel

Higher strength allows thinner walls, reducing weight. Excellent toughness ensures safety against brittle failures. Resistance to cracking and corrosion also makes it suitable for demanding services.

Testing and Certification

Meets all hydrostatic and flattening tests as per ASTM A106. Mill test reports include chemical analysis and pressure tests conducted to certify the pipe quality.

A618 steel Pipe We Supply

Shangang Steel supplies A618 seamless pipes of different specifications to meet the different needs of customers. Please view the seamless pipe specification table we supply here. A618 seamless pipe lengths can be customized to meet the needs of your specific project.

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