ASTM A500 Pipe


ASTM A500 Hollow Section

ASTM A500 is a specification established by the American Society for Testing and Materials (ASTM) for cold-formed welded and seamless carbon steel structural tubing in round, square, and rectangular shapes.

UNIACERO is proud to present the ASTM A500 structural steel tubing in a wide range of sizes and shapes. The ASTM A500 specification covers cold-formed welded and seamless carbon steel tubing, available in various forms:

  • Carbon Steel Round Tubing
  • Carbon Steel Square Tubing
  • Carbon Steel Rectangular Tubing
  • Special Carbon Steel Shapes

These products are ideal for welded, riveted, or bolted construction applications, as well as for general structural purposes.

ASTM A500 Carbon Steel Structural Tubing Specifications & Requirements

Our ASTM A500 specification covers cold-formed welded and seamless carbon steel structural tubing in round, square, rectangular, and “special” shapes for construction and general structural purposes. Here are the key aspects of the ASTM A500 specification:

Production StandardASTM A500
Manufacturing ProcessesERW (Electric Resistance Welding)
SSAW (Spirally Submerged Arc Welding)
LSAW (Longitudinal Submerged Arc Welding)
SMLS (Cold Drawn Seamless)
Outside Diameter13.7mm – 2235mm (1/4″ – 88″)
Wall Thickness1.65mm – 25.4mm
Pipe Length1.5 – 18 meters
Steel GradeASTM A500 Grade AASTM A500 Grade C
ASTM A500 Grade BASTM A500 Grade D
Corrosion PreventionLacquer, Varnish, Oiling, Galvanizing
End ProcessesSquare Cut, Bevelling, Threading, Grooving
Further ProcessingWelding, Bending, Hole Drilling, Punching, Swaging, Tapering, Flaring, Expanding

ASTM A500 Dimension Table


For round structural tubing, outside diameters of 1.900” (48.26mm) or smaller have a precise variation of ±0.5%, while those with nominal ODs of 2” (50.8mm) and larger have a variation of ±0.75%. Square and rectangular structural tubing dimensions are measured across the flats, and we ensure that specified dimensions adhere strictly to the given plus/minus allowances.

Besides, our commitment to accuracy extends to wall thickness, ensuring that it meets the specified standards for a diverse range of structural applications.

Below are dimension table for ASTM A500 structural tubing, outlining typical sizes and wall thicknesses available for round, square, and rectangular tubing.

Square Hollow Section Thickness: 1.000 in. [25.4 mm] or less
Size (mm)
20 x 2080 x 80180 x 180
25 x 2590 x 90200 x 200
30 x 30100 x 100225 x 225
38 x 38110 x 110240 x 240
40 x 40120 x 120250 x 250
50 x 50125 x 125300 x 300
60 x 60130 x 130350 x 350
65 x 65140 x 140400 x 400
70 x 70150 x 150450 x 450
75 x 75160 x 160500 x 500
Rectangular Hollow Section Thickness: 1.000 in. [25.4 mm] or less
Size (mm)
20 x 30120 x 40250 x 75
40 x 20120 x 50250 x 100
40 x 25120 x 60250 x 150
40 x 30120 x 80250 x 200
50 x 25120 x 100300 x 100
50 x 30140 x 60300 x 150
50 x 40140 x 80300 x 180
60 x 30150 x 50300 x 200
60 x 40150 x 75400 x 200
70 x 50150 x 100400 x 300
80 x 40160 x 60400 x 350
80 x 50160 x 80450 x 250
80 x 60180 x 120500 x 200
90 x 60180 x 140500 x 300
100 x 40200 x 50500 x 400
100 x 50200 x 60600 x 200
100 x 60200 x 80600 x 300
100 x 80200 x 100600 x 400
Steel Pipe Dimensions Chart ANSI B36. 10 & 36.19
Nominal Pipe SizeOutside Diameter (mm)Nominal Wall Thickness Schedule
1 1/43242.21.652.772.973.563.564.854.85
1 1/24048.31.652.773.183.683.685.085.08
2 1/265732.113.054.785.
3 1/290101.
Nominal Pipe SizeOutside Diameter (mm)Nominal Wall Thickness

Chemical Requirements of ASTM A500 Steel

When it comes to the composition of our ASTM A500 Carbon Steel Structural Tubing, we’re transparent and stringent. The chemical composition of our tubing aligns with the ASTM A500 standard. We use materials that primarily consist of iron, enhanced with added elements like carbon, manganese, phosphorus, sulfur, and copper. This combination guarantees the durability and performance of our products, making sure they are consistently up to the mark.

In addition, we utilize suitable measuring devices to ensure the accuracy of these components. This precision in chemical composition contributes to the reliability and suitability of our tubing for diverse structural applications, including bolted construction and seamless carbon steel structures.

Check out the chart below for exact A500 carbon steel chemical specifications.

Chemical Requirements
ElementComposition, %
Grades B and DGrade C
Carbon, maxA0.260.300.230.27
Manganese, maxA1.351.401.351.40
Phosphorus, max0.0350.0450.0350.045
Sulfur, max0.0350.0450.0350.045
Copper, minB0.
A  For each reduction of 0.01 percentage point below the specified maximum for carbon, an increase of 0.06 percentage point above the specified maximum for manganese is permitted, up to a maximum of 1.50 % by heat analysis and 1.60 % by product analysis. B  If copper-containing steel is specified in the purchase order.

A500 Carbon Steel Mechanical Properties

Mechanical strength defines the quality of any structural tubing. Our ASTM A500 Carbon Steel Structural Tubing boasts impressive tensile strength, showcasing its capability to withstand stretching stress effectively. The ultimate tensile strength of our product is derived from extensive testing and evaluations, ensuring that A500’s performance aligns with your project’s demands.

A500 carbon steel’s tensile strength is described in the chart below:

Tensile Requirements
Round, Square, Rectangular, and Special Tubular Shapes
Mechanical PropertiesGrade BGrade CGrade D
Tensile strength, min, psi [MPa]58 00062 00058 000
Yield strength, min, psi [MPa]46 00050 00036 000
Elongation in 2 in. [50 mm], min, %C23A21B23A

A   Applies to specified wall thicknesses (t ) equal to or greater than 0. 180 in. [4.57mm]. For lighter specified wall thicknesses, the minimum elongation values shall be  calculated  by the formula:  percent  elongation  in 2  in.  [50  mm]  =  61t +  12, rounded to the nearest percent. For A500M use the following formula: 2.4t + 12, rounded to the nearest percent.

B    Applies to specified wall thicknesses (t ) equal to or greater than 0. 120 in. [3.05mm]. For lighter specified wall thicknesses, the minimum elongation values shall be by agreement with the manufacturer.

C    The minimum elongation values specified apply only to tests performed prior to shipment of the tubing.

Steel Grades in ASTM A500 Tubing

UNIACERO’s ASTM A500 Carbon Steel Structural Tubing is available in various grades to cater to different requirements. Our tubing is available in four grades (Grade A, Grade B, Grade C, and Grade D), each with specific requirements, including minimum yield strength and outside dimensions. Grade A exhibits tensile strength of 45,000 psi and yield strength of 39,000 psi. For projects demanding more strength, Grade B, C, and D are available with their respective strengths and elongations. Each grade is meticulously crafted to serve specific needs, providing you with a robust and reliable solution for various structural applications.

ASTM A500 Grade A

  • Yield Strength: 39,000 psi minimum
  • Tensile Strength: 45,000 psi minimum
  • Elongation: 25% minimum in 2 inches
Grade A is typically used for general structural purposes where welding and bending are moderately stressful.

ASTM A500 Grade B

  • Yield Strength: 46,000 psi minimum
  • Tensile Strength: 58,000 psi minimum
  • Elongation: 23% minimum in 2 inches
Grade B is widely used for structural applications requiring more strength than Grade A, such as building columns and frames.

ASTM A500 Grade C

  • Yield Strength: 50,000 psi minimum
  • Tensile Strength: 62,000 psi minimum
  • Elongation: 21% minimum in 2 inches
Grade C offers higher strength compared to Grade B and is suitable for more demanding structural applications.

ASTM A500 Grade D

  • Yield Strength: 58,000 psi minimum
  • Tensile Strength: 67,000 psi minimum
  • Elongation: 21% minimum in 2 inches

Grade D provides the highest strength within ASTM A500 and is used in applications requiring superior load-bearing capacity.

Each grade of ASTM A500 carbon steel tubing is designed to meet specific mechanical and structural requirements, offering a range of options for engineers and designers in various construction and infrastructure projects. Understanding the properties and applications of each grade is crucial for selecting the appropriate material for your project needs. Always refer to the latest ASTM A500 standard for detailed specifications and requirements regarding steel grades and other considerations.

Production Tolerance of ASTM A500

Engineers often wonder why there are significantly fewer options for A53 pipes compared to A500 pipes.

A53 pipes are designated using a nominal pipe diameter in inches, along with one of three scheduled wall thicknesses. They are sized this way to accommodate A53 pipes’ intended purpose—transporting pressurized steam, air, or water—requiring compatibility with standardized fittings and valves.

Such requirements are not applicable to A500 tubes, allowing for more precise and efficient designation. A500 rounds include the outside diameter and wall thickness in inches, measured to three decimal places. For example, when using an A500 round for a building column, an HSS8.625×0.322 can be specified with an outside diameter (OD) tolerance of +/-0.75% and a wall tolerance of +/-10%. In contrast, the A53 equivalent, an 8-inch standard pipe, has an OD tolerance of +/-1% and a wall tolerance of -12.5%. This highlights that A500 rounds have superior OD and wall tolerances.

Choose A500 rounds for your structural tubing needs, benefiting from their superior tolerances and the flexibility they offer in meeting specific requirements for wall thickness and outside diameter

A500 Outside Dimensional Tolerances for Square & Rectangular Steel tubing

The chart below describes the exact outside dimensional tolerances for A500 carbon steel.
Outside Large Flat Dimension, in. (mm)Large Flat Dimension Tolerance, A plus and minus, in. (mm)
2 12 (63.5) or under0.020 (0.51)
Over 2 12 to 3 12 (63.5 to 88.9), incl.0.025 (0.64)
Over 3 12 to 5 12, inc.0.030 (0.76)
Over 5 12 (139.7)0.01 times large flat dimension

A500 Outside Dimensional Tolerances for Square & Rectangular Steel tubing

A500 Outside Dimensional Tolerances for Square Tubing

1. Outside Dimensions (Width and Height):

The outside dimensions (width and height) of square tubing are typically subject to the following tolerances:
Width and Height Tolerance: +/- 0.020″ (0.5 mm)

2. Squareness of Sides:
The difference between diagonals of the same cross-section must not exceed 1% of the nominal dimensions.

A500 Outside Dimensional Tolerances for Rectangular Tubing

1. Outside Dimensions (Width and Height):

The outside dimensions (width and height) of rectangular tubing are typically subject to the following tolerances:

  • Width Tolerance: +/- 0.020″ (0.5 mm)
  • Height Tolerance: +/- 0.010″ (0.25 mm)


2. Squareness of Sides:

The difference between diagonals of the same cross-section must not exceed 1% of the nominal dimensions.

If you have specific tolerance requirements for your project, it’s advisable to communicate these requirements clearly with UNIACERO’s engineer.

A500 Carbon Steel Twist Tolerances for Square & Rectangular Structural Tubing

ASTM A500 does not specifically provide twist tolerances for square and rectangular structural tubing. However, twist tolerance requirements can be derived from general industry standards and practices applicable to structural steel products.

Twist is typically defined as the rotation of one end of the tubing relative to the other end along the longitudinal axis. It is measured in degrees per unit length (e.g., degrees per foot).

  • Maximum Twist: The maximum twist allowable for square and rectangular tubing is often specified as a certain number of degrees per specified length (e.g., per foot).
  • Industry Standards: Industry standards such as ASTM A6/A6M, which covers general requirements for rolled structural steel bars, plates, shapes, and sheet piling, may provide guidance on allowable twist tolerances indirectly applicable to structural tubing.
  • Common Practice: In practice, twist tolerances for square and rectangular tubing can vary depending on the manufacturing method, size, and specific customer requirements.

Typically, twist tolerances are specified based on customer drawings, project specifications, or agreed-upon standards between the manufacturer and customer.

Manufacturing Process of ASTM A500 ERW Structural Pipe

ASTM A500 ERW Pipe Manufacturing Process

ASTM A500 Carbon Steel Structural Tubing Benefits

ASTM A500 carbon steel structural tubing combines strength, durability, and versatility, making it a preferred choice for engineers and architects in diverse construction and industrial applications.

  • High Strength: Designed to withstand significant loads and stresses, providing structural integrity and reliability.
  • Durability: Resistant to wear, abrasion, and environmental factors, ensuring long-term performance in various conditions.
  • Wide Range of Shapes: Available in round, square, rectangular, and special shapes, catering to diverse structural design requirements.
  • Various Sizes: Offers flexibility with a range of sizes and dimensions, accommodating different project needs.
  • Economical Production: Cold-formed manufacturing process is cost-effective compared to hot-rolled steel, without compromising quality or strength.
  • Weldability: Easily weldable using standard welding techniques, facilitating efficient fabrication and assembly.
  • Machinability: Can be cut, drilled, and machined to precise specifications, enhancing flexibility in construction.


For more information regarding premium ASTM A500 carbon steel structural tubing, contact UNIACERO at +86 (022) 8837 8999. Our team will gladly discuss the specific requirements of your next project.

Reference Resource

Our Advantages

  1. Over 25 years of experience in pipeline production and installation.
  2. Comprehensive inspection equipment.
  3. Independent product serial numbers for traceability.
  4. Advanced production equipment – Seamer high-frequency welding machine from the United States.
  5. Complete qualifications – API 5L/API 5CT/FM/UL fire pipe certification, etc.
  6. Wide range of products – independently developed solar torque tubes, highly favored in the European market.
  7. Customers spread across the globe.
  8. Excellent after-sales service and sense of responsibility.

Application Scenarios

Our steel pipes are engineered to withstand high temperatures, corrosive environments, and varying pressures, ensuring reliability and safety in the complex petrochemical processes. 

Whether it’s transferring crude oil, natural gas, or chemical intermediates, the robustness and versatility of steel pipes make them indispensable components of the plant’s infrastructure, contributing to efficient production and maintenance of stringent safety standards.

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