Welded versus seamless routes
ASTM A513 vs ASTM A519
A513 covers ERW mechanical tubing; A519 covers seamless carbon and alloy steel mechanical tubing. Process, availability, and requirements differ.
On this page
The short answer
Both are mechanical tubing specifications; the dividing line is the production route. A513 product is welded from strip (with or without subsequent drawing); A519 product is seamless, produced from solid billet. Seamless is not automatically better — it is a different process with different strengths: no weld zone to consider, broader alloy and heavy-wall availability, but generally at higher cost and with its own dimensional character.
DOM (A513 Type 5) is the usual point of confusion: it is drawn, refined, welded tube — not seamless. Many applications once assumed to require seamless are served well by DOM at lower cost; genuinely critical pressure, fatigue, or alloy requirements may still point to A519. That is an engineering decision.
Choose from functional requirements
A seamless route is not automatically better, and DOM is not seamless. Evaluate pressure or fatigue design basis, machining stock, dimensional needs, weld acceptance, grade availability, quantity, and cost with qualified engineering and supplier input.
| Aspect | ASTM A513 (welded) | ASTM A519 (seamless) |
|---|---|---|
| Production | ERW from strip; may be drawn | Seamless from billet |
| Weld zone | Present (worked in drawn types) | None |
| Alloy/heavy-wall range | Carbon and some alloy | Broader alloy and wall range |
| Typical relative cost | Lower | Higher |
| Common misconception | “DOM is seamless” — it is not | “Seamless is always better” — not always |
Common specification mistakes
Writing “seamless or DOM” on a drawing as if equivalent; specifying A519 for cost-sensitive parts a drawn A513 route would satisfy; and carrying a legacy seamless callout forward without re-validating the actual requirement.
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.