Evidence and limitations
Sources and methodology
Normative requirements come from the official standard. This publication provides independent explanation and calculation tools.
On this page
Primary source
The active edition referenced by this publication is ASTM A513/A513M-25, Standard Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing. Purchase and consult the official document for controlled requirements.
Source hierarchy
Where sources could conflict, this publication treats them in this order: (1) the current official ASTM edition; (2) producer certifications and documented capability for a specific order; (3) established manufacturing references and practitioner experience for process explanation. Nothing in tier 3 is ever presented as a normative requirement.
What we do not publish
We do not reproduce paid tolerance, chemistry, or mechanical-property tables; invent supplier capability; or imply that a web calculator establishes conformance.
Calculation methodology
Calculators on this site show their formulas and assumptions inline. Theoretical weight uses nominal dimensions and a stated steel density; estimator tools state that outputs are planning aids. None of the tools measure product, and none of their outputs are acceptance criteria.