Alleima composite tubes are made of two different metals joined together, each selected for its unique properties like corrosion resistance, thermal conductivity, or strength. This combination in a single tube offers the optimal properties of both metals.
These tubes are often used in boilers or heat exchangers, where one metal offers corrosion resistance or compatibility with specific fluids, while the other metal provides structural strength or thermal conductivity.
Typical application areas
Our composite tubes are often used in steam boilers and other processing equipment operating under corrosive conditions, including:
- Black liquor recovery boilers (BLRB)
- Syngas coolers
- Waste heat boilers
- Waste-to-energy boilers
Superior to overlay welded tube
Alleima’s advanced fabrication methods for composite tube involve co-extrusion of the two materials with a homogenous bond zone, ensuring even bonding and the highest quality product. Compared to traditional overlay welding, this process results in straighter, more uniform tube. For instance, in applications such as BLRB superheater tube, overlay tubes often encounter issues related to physical bonding, and melted bonds may lead to content dilution – all of which are avoided with our range!
More than 400 boilers
Since the 1970s, Alleima composite tubes have been installed in more than 400 boiler units worldwide. 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 |