ASTM A513 Rectangular Tube Sizes

ASTM A513 rectangular tubes are available in a wide range of sizes to meet different mechanical and fabrication requirements. Although ASTM A513 does not specify a fixed dimensional chart, it covers electric resistance welded (ERW) mechanical tubing manufactured in various outside dimensions and wall thicknesses. Standard rectangular tube sizes typically range from 1 × 1.5 in. to 4 × 6 in. for stock products, while custom sizes can extend from 10 × 15 mm to 800 × 1100 mm, depending on the manufacturing process and mill capabilities. Wall thicknesses generally range from 0.020 in. (0.5 mm) to 1.000 in. (25 mm).For dimensions across multiple international standards and materials, see our Standard Rectangular Tube Size Table.

ASTM A513 is the standard specification for electric resistance welded (ERW) carbon and alloy steel mechanical tubing, including round, square, and rectangular shapes. Compared with ASTM A500 structural tubing, ASTM A513 places greater emphasis on dimensional accuracy, surface finish, and machinability, making it widely used in automotive components, machinery, agricultural equipment, conveyor systems, furniture, and other precision fabrication applications.

This guide provides standard ASTM A513 rectangular tube sizes, wall thicknesses, dimensions, specifications, and a comparison with ASTM A500 to help engineers, fabricators, and buyers select the right mechanical tubing for their applications.

ASTM A513 Rectangular Tube Sizes Chart

ASTM A513 rectangular tubing is manufactured in a wide range of outside dimensions and wall thicknesses. The standard itself specifies manufacturing requirements and tolerances rather than fixed dimensions, so available sizes may vary by manufacturer.
The following table lists some of the most commonly supplied ASTM A513 rectangular tube sizes.

Outside Dimensions (in.)	Wall Thickness (in.)	Approx. Weight (lb/ft)
1 × 1/2	0.065	0.7
1-1/2 × 1/2	0.065	0.82
1-1/2 × 3/4	0.065	0.94
1-1/2 × 3/4	0.083	1.18
1-1/2 × 1	0.065	1.05
1-1/2 × 1	0.083	1.32
2 × 1	0.065	1.3
2 × 1	0.12	2.25
2 × 2	0.12	2.93
2 × 3	0.12	3.53
2 × 4	0.188	7.35
2 × 6	0.25	11
3 × 4	0.25	13.2
4 × 6	0.25	16.9

Note: Manufacturers can also produce custom dimensions and wall thicknesses to meet specific fabrication or OEM requirements.

Standard Wall Thickness of ASTM A513 Rectangular Tubes

ASTM A513 rectangular tubes are available in multiple wall thicknesses to satisfy different mechanical and fabrication requirements. Thinner walls help reduce weight and material costs, while heavier walls provide greater rigidity and load resistance for demanding applications.
Common wall thicknesses include:

Gauge	Wall Thickness
16 Gauge	0.065 in
14 Gauge	0.083 in
11 Gauge	0.120 in
3/16 in	0.188 in
1/4 in	0.250 in
5/16 in	0.313 in
3/8 in	0.375 in

For most mechanical fabrication projects, wall thicknesses between 0.065 in and 0.120 in are the most commonly used because they offer an excellent balance between strength, weight, and ease of machining. Heavier wall sections are typically selected for equipment frames, trailers, and industrial machinery that require additional stiffness.

ASTM A513 Size Range

One common misconception is that ASTM A513 defines a fixed list of tube sizes. In fact, the specification focuses on manufacturing quality, dimensional tolerances, and material requirements rather than prescribing standard dimensions.
Most steel service centers stock rectangular tubing in sizes ranging from 1 × 1/2 inch up to 4 × 6 inches, while mills can manufacture significantly larger custom sections depending on production capabilities and order quantities.
When specifying ASTM A513 tubing, engineers generally identify four key dimensions:
Outside height (H)
Outside width (W)
Wall thickness (T)
Tube length (L)
For example:
2 × 4 × 0.188 × 20 ft ASTM A513 Rectangular Tube
This designation describes a tube with a 2-inch height, 4-inch width, 0.188-inch wall thickness, and a total length of 20 feet.

ASTM A513 Specifications

ASTM A513 covers electric-resistance-welded (ERW) carbon and alloy steel mechanical tubing intended for applications that require precise dimensions, a smooth surface finish, and consistent mechanical performance. Unlike structural tubing specifications that focus on load-bearing capacity, ASTM A513 is designed for components that will be machined, fabricated, bent, or assembled into mechanical equipment.
The specification includes several manufacturing types, with Type 1 (As-Welded) and Type 5 (Drawn Over Mandrel, DOM) being the most widely used in industry.
Typical ASTM A513 rectangular tubing features include:

Specification	Description
Manufacturing Process	Electric Resistance Welded (ERW)
Product Shape	Rectangular, Square, Round, Special Shapes
Material	Carbon Steel / Low Alloy Steel
Surface Finish	Mill Finish or Light Oil Coating
Dimensional Accuracy	High
Weldability	Excellent
Machinability	Excellent
Formability	Good

One important point to understand is that ASTM A513 does not prescribe a fixed strength level for every tube. Mechanical properties depend on the steel grade and manufacturing type selected. For example, DOM tubing generally offers higher strength and better dimensional consistency than standard as-welded tubing.

ASTM A513 vs ASTM A500: What's the Difference?

Although ASTM A513 and ASTM A500 are both commonly manufactured using the ERW process, they are designed for different purposes. Choosing the correct specification depends on whether your project requires precision or structural performance.

Feature	ASTM A513	ASTM A500
Primary Use	Mechanical Tubing	Structural Tubing
Main Priority	Dimensional Accuracy	Structural Strength
Manufacturing	ERW	ERW
Surface Finish	Smooth	Standard Mill Finish
Dimensional Tolerance	Tight	Standard
Typical Applications	Machinery, Automotive, Equipment	Buildings, Bridges, Steel Structures

In practical applications, ASTM A513 is often selected when accurate outside dimensions are essential, such as for machine frames, conveyor systems, agricultural equipment, or automotive components. Tight tolerances help reduce machining time and improve assembly accuracy.
By contrast, ASTM A500 is the preferred choice for load-bearing structures, including columns, building frames, sign supports, and other structural members where yield strength and structural performance are the primary design considerations.
If your project involves fabrication rather than structural engineering, ASTM A513 is generally the more suitable option.