Composite tube (compound tube) suitable for applications where the conditions outside and inside the tube require material properties that cannot be met by one material only.
The composite tube consists of two different alloys metallurgically bonded together to achieve good thermal transfer properties. One alloy is used to withstand corrosion, while the other is often an approved pressure vessel material.
Typical applications for our composite tubes are steam boilers with corrosive conditions, such as:
- Black liquor recovery boilers (BLRB)
- Syngas coolers
- Waste heat boilers
- Waste-to-energy boilers
We composite tubes have been installed in more than 400 boiler units worldwide since the 1970s. Contact us for references.
| Grade | UNS | ASTM/ ASME |
EN no. | EN name |
|---|---|---|---|---|
| Corrosion resistant alloys | ||||
| Sanicro® 67 | N06690 | - | 2.4642 | - |
| Sanicro® 38 | N08825 Mod. | - | 2.4858 | - |
| Sanicro® 30 | N08800 | - | 1.4558 | - |
| Sanicro® 28 | N08028 | - | 1.4563 | X1NiCrMoCu31-27-4 |
| 3RE28 | - | 310 | 1.4845* | - |
| 3R12 | S30403/ S30400 |
304L | 1.4306 | - |
| Load carrying alloys, pressure bearing components | ||||
| 4L7 | - | SA210-A1 (C) | 1.0425 | P265GH |
| 3Mo1 | - | - | 1.5415 | 16Mo3 |
| HT5 | - | SA213-T12 | 1.7335 | 13CrMo4-5 |
| HT8 | - | SA213-T22 | 1.7380 | 10CrMo910 |
| T23 | SA213-T23 | 1.8201 | 7CrWVMoNb9-6 | |
| T24 | - | SA213-T24 | 1.7378 | 7CrMoVTiB10-10 |
| HT7 | - | SA213-T91 | 1.4903 | X10CrMoVNb9-1 |
* According to EN 10095, valid for heat resistant grades in the form of sheet/plate, strip, semi-finished products, bar, rod and sections (not for pressure or creep purposes).
| Outside diameter | Total minimum wall thickness |
Thickness outer layer |
Minimum thickness inner layer |
||||
|---|---|---|---|---|---|---|---|
| mm | in. | mm | in. | mm | in. | mm | in. |
| 38.0 | 1 1/2 | 5.00 | 0.197 | 1.30 | 0.051 | 3.70 | 0.146 |
| 50.8 | 2 | 5.08 | 0.200 | 1.50 | 0.059 | 3.58 | 0.141 |
| 63.5 | 2 1/2 | 6.53 | 0.257 | 1.65 | 0.065 | 4.88 | 0.192 |
| 76.2 | 3 | 6.58 | 0.259 | 1.65 | 0.065 | 4.93 | 0.194 |