Mechanical versus structural
ASTM A513 vs ASTM A500
A513 addresses mechanical tubing; A500 addresses structural carbon steel tubing. They are not interchangeable labels.
On this page
The short answer
A500 is a structural specification: it exists so that designers can rely on specified minimum mechanical properties for load-bearing members, and it is the family building codes reference for hollow structural sections (HSS). A513 is a mechanical-tubing specification: it prioritizes manufacturing route, dimensional communication, and fabrication behavior for components.
If a structural engineer's calculation or a building code references the tube, A500 governs. If the tube becomes a machined, formed, or assembled component, A513 is usually the better ordering language. Substituting one for the other requires engineering approval, not a purchasing decision.
Different design intent
Select A500 when structural specification requirements govern. Select A513 when mechanical-tubing process, dimensions, finish, or fabrication performance govern. Engineering approval is required before substitution.
| Aspect | ASTM A513 | ASTM A500 |
|---|---|---|
| Design intent | Mechanical components | Structural members |
| Typical reference | Part drawings, RFQs | Building codes, structural calcs |
| Property basis | By grade/condition as ordered | Specified minimums by grade |
| Process emphasis | Route (Types 1–6) is central | Cold-formed welded or seamless |
| Typical buyer question | Will it machine and fit? | Will it carry the load? |
Purchasing implication
A familiar nominal size does not establish equivalence. Compare scope, grade, properties, tolerances, testing, certification, and design-code requirements.
The reverse substitution — using A500 where A513 was specified — can also fail: structural tube is not produced with machining stock, surface finish, or ID condition in mind.
Sources and limitations
- ASTM A513/A513M — Standard Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing — ASTM International. Controlling specification for types, tolerances, and ordering requirements. Purchase the current edition for all normative values.
These sources inform the qualitative guidance on this page. This publication does not reproduce their text, tables, numerical settings, or acceptance criteria. Normative requirements come only from the purchased current edition of the governing standard and your supplier agreement.