Engineering Calculation Tools
A first design-stage estimate for EAF fourth-hole elbows, dedusting ducts, and high-temperature piping runs. The result is calculated from real EN 1993-1-2 carbon steel data — not a constant-coefficient assumption.
This calculator was built specifically for EAF fourth-hole elbows, dedusting ducts, gas ducts, and compensator sizing.
Length Change
104 mm
Expansion
This calculation is an approximate starting value based on EN 1993-1-2 carbon steel data. For an exact design, talk to DNL's engineers.
The calculation uses the formula defined in EN 1993-1-2, clause 3.4.1.1:
ΔL = L × ( e(T_operating) − e(T_installation) )
Where L is the installed length of the pipe or duct, and e(T) is the unit thermal expansion of carbon steel per EN 1993-1-2 clause 3.4.1.1, valid from 20 to 1200°C.
Between 750 and 860°C the expansion stays nearly flat — this is the ferrite-to-austenite phase transformation, not an error in the data.
Enter the metal wall temperature of the pipe or duct — not the flue gas temperature flowing through it. In an EAF duct these can differ by hundreds of degrees.
For a 10 m carbon steel run heated from 20°C to 500°C: the commonly used constant coefficient (12×10⁻⁶ /°C) predicts 57.6 mm of expansion. EN 1993-1-2's actual carbon steel data gives 67.6 mm — meaning the constant-coefficient approach underestimates the real value by 14.8%. At high temperature, that gap can become a real design error in compensator sizing.
A 12 m dedusting duct run, installed at 20°C, grows by roughly 100.8 mm at a 600°C operating temperature. That movement has to be absorbed by properly sized compensators, not fought by the structure.
Assumptions: a 10 m carbon steel run, installed at 20°C.
| Operating Temperature (°C) | Expansion (mm) |
|---|---|
| 100 | 10 |
| 200 | 23.2 |
| 300 | 37.2 |
| 400 | 52 |
| 500 | 67.6 |
| 600 | 84 |
| 700 | 101.2 |
| 800 | 110 |
| 900 | 118 |
| 1000 | 138 |
| 1200 | 178 |
A 12 m dedusting duct run, installed at 20°C, expands by roughly 100.8 mm at a 600°C operating temperature — a real figure calculated from EN 1993-1-2 carbon steel data.
Carbon steel's expansion rate is not linear with temperature, and it nearly flattens between 750 and 860°C due to the ferrite-to-austenite phase transformation. Using a constant coefficient diverges noticeably from the real value, especially above 400°C.
Enter the metal wall temperature. Flue gas temperature and the actual pipe or duct wall temperature can differ by hundreds of degrees, especially on insulated or cooled runs — it's the metal that determines the expansion, not the gas.
That range is carbon steel's ferrite-to-austenite phase transformation. As the crystal structure changes, the material tends to contract slightly, which largely cancels out thermal expansion over that band — producing the near-flat plateau.
No. This tool works only with carbon steel data per EN 1993-1-2. Stainless steel's expansion coefficient depends on the grade, and the two families differ markedly: austenitic grades (1.4301, 1.4404, 1.4541) run roughly 16-18×10⁻⁶/°C, while ferritic grades (1.4509, 1.4521) run roughly 10-11×10⁻⁶/°C — much closer to carbon steel. Picking the right grade changes the result substantially, and the value must come from a verified manufacturer datasheet — contact DNL's engineers and we'll work out the figure for your project.
