Finished Tube ID & Torque Calculator
The below calculator can help you determine your finished ID target and recommended torque for expansion.
Calculator
NOTE: The calculated values are estimated based on the available inputs. Actual values may vary due to tube thickness, material, tube sheet thickness, lubrication, operation condition, and/or operator technique. Best practices are to start with a lower torque setting and measure each tube to ensure proper wall reduction and finished ID is achieved.
BWG / Wall Thickness (Inch) Conversion Chart
| Tube Wall BWG | Tube Wall Inches |
|---|---|
| 0 | 0.340 |
| 1 | 0.300 |
| 2 | 0.284 |
| 3 | 0.259 |
| 4 | 0.238 |
| 5 | 0.220 |
| 6 | 0.203 |
| 7 | 0.180 |
| 8 | 0.165 |
| 9 | 0.148 |
| 10 | 0.134 |
| 11 | 0.120 |
| 12 | 0.109 |
| 13 | 0.095 |
| 14 | 0.083 |
| 15 | 0.072 |
| 16 | 0.065 |
| 17 | 0.058 |
| 18 | 0.049 |
| 19 | 0.042 |
| 20 | 0.035 |
| 21 | 0.032 |
| 22 | 0.028 |
| 23 | 0.025 |
| 24 | 0.022 |
| 25 | 0.020 |
| 26 | 0.018 |
Industry Recommended Wall Reductions
| Material | TEMA Standard Target % Wall Reduction | API-660 Target % Wall Reduction |
|---|---|---|
| Aluminum 3003 or 4004 | 4 – 6% | 5 – 7% |
| Aluminum 6061-T | 6 – 9% | 8 – 10% |
| Carbon Steel & low-alloy steel (max 9% Chromium) | 5 – 8% | 8% max* |
| Stainless Steel and high-alloy steel | 5 – 8% | 6% max* |
| Duplex Stainless Steels | 4 – 6% | Not Specified** |
| Titanium (and other nonferrous, work hardening materials) | 4 – 6% | 5% max* |
| Admiralty Brass (and other nonferrous, non-work hardening materials) | 4 – 9% | 8%* |
| Copper & Copper Alloys | 7 – 10% | Not Specified |
Additional Resources
Tube Expander Design & Usage
Choosing the right expander to suit your needs.
What Is Parallel Pin Expansion?
With parallel pin expansion, the rolls are set parallel with the mandrel with zero feed angle. This means that the mandrel will not self-feed as a traditional expander would. Instead, the mandrel is pushed through the expander by force, in most cases hydraulic, allowing the tube to expand.
Why Won’t This Tube Expand
When expanding heat exchanger tubes, achieving the proper wall reduction is crucial for a secure and leak-free seal. Sometimes, however, tubes fail to expand sufficiently, hindering the integrity of the vessel. This article outlines common causes and troubleshooting steps for incomplete tube expansion.