ASTM A500 vs A513: Structural vs Mechanical Tubing

What is ASTM A500 (Structural Tubing)?

ASTM A500 is a standard specification for cold-formed welded and seamless carbon steel structural tubing. Such tubing is commonly referred to as "Hollow Structural Sections" (HSS).

● Main Function: Load-bearing and structural integrity. It is designed to withstand significant compressive, bending, and torsional forces.
● Appearance: Often used in construction projects where the visual appearance of the steel is important (e.g., exposed columns).

● Technical Documentation: When ordering tubing to the A500 specification, the manufacturer must provide a report detailing its chemical composition, yield strength, tensile strength, and elongation. This report on physical properties is a key feature that distinguishes it from products manufactured under the A513 standard.

● Common Applications: Building frameworks, bridge support structures, crane booms, and Roll-Over Protective Structures (ROPS) for heavy machinery.

What is ASTM A513 (Mechanical Tubing)?

ASTM A513 is the standard specification for electric-resistance-welded (ERW) carbon and alloy steel mechanical tubing.

● Key Characteristics: It emphasizes precision and machinability. Compared to the A500 standard, it requires stricter dimensional tolerances and offers a superior surface finish.
● Lack of Structural Performance Guarantees: Unlike A500, the A513 standard does not provide the same rigorous guarantees regarding the load-bearing capacity of the material itself. This type of tubing is intended to be processed—via machining, bending, or forming—into a final product.
● Common Applications: Hydraulic cylinders, lawnmower handles, automotive components, and recreational vehicle (RV) parts.

Summary: Key Differences

The simplest way to remember the distinction is: A500 is intended for structural (construction) applications, while A513 is intended for mechanical (machining) applications.

Tolerances: A513 has stricter tolerance requirements.
Cost: A513 is generally more expensive due to the additional processing steps involved.
Weld Seams: A500 is typically used in the "as-welded" condition (unless otherwise specified). A513, by contrast, often undergoes further processing—such as the DOM (Drawn Over Mandrel) process—to smooth out the weld seam, making it suitable for machining purposes.

(👉 Looking for precision A513 mechanical steel tubing?  See our [ASTM A513 Mechanical Steel Tubing].)

Wait, how does this relate to "Mechanical vs. Structural"?

A500 structural tubing is what you use when you're building a structure, while A513 mechanical tubing is what you use when you're machining parts. (👉 For a deeper dive into the differences between the two, their respective tolerance standards, and their applications, please refer to: [Mechanical Tubing vs. Structural Tubing])