KEVOS® MAKEOS · Fabrication
Length of Angle or Bar Bent to a Ring
What length of angle iron or bar do I cut to roll this ring inside or outside a tank?
Cut length of an angle, flat or other section rolled into a ring, from the diameter at the back of the section and the distance to its neutral axis, or from a handbook-style length constant, for sections placed inside or outside a tank or stack.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Correction from | choice | Use the section’s neutral-axis distance, or a length constant for the section. |
| Section is | choice | Whether the section sits inside or outside the shell. |
| Shell diameter at the back of the section | mm | Diameter of the shell surface that the back of the section bears on. |
| Back of section to neutral axis | mm | Distance from the back of the section to its neutral axis (centroid) in the plane of bending, from section data. |
| Length constant | mm | Length constant to subtract (inside) or add (outside), equal to 2π × the neutral-axis distance. |
Method and formulas
- Neutral-axis diameter = D − 2x inside the shell, D + 2x outside.
- Length = π × neutral-axis diameter = π D ∓ 2π x.
- Handbook example: 20 ft inside diameter with a constant of 4.319 in gives 754 − 4.319 = 749.68 in.
- Example: 6096 mm inside a shell with 22.5 mm to the neutral axis needs 19,010 mm.
Limitations
- Neutral axis assumed at the centroid; heavy rolling can shift it slightly.
- Add allowance for the ends to be trimmed after rolling.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Cut stiffener rings for tanks, ducts and stacks
- Estimate material for rolled flanges
- Check rolled ring length allowances
Who it is for
- Fabrication supervisors
- Manufacturing engineers
- Estimators
What you get
- Cut length
- Neutral-axis diameter
- Correction to the circumference
Interpreting the result
- Roll a trial ring for new sections and adjust the constant from the measured result.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2593. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
