Composite tube for boilers

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 Sandvik composite tubes are steam boilers with corrosive conditions, such as:

  • Black liquor recovery boilers (BLRB)
  • Syngas coolers
  • Waste heat boilers
  • Waste-to-energy boilers

Sandvik composite tubes have been installed in more than 400 boiler units worldwide since the 1970s. Contact us for references.

Composite tube materials
Sandvik gradeUNSASTM/
ASME
EN no.EN name
Corrosion resistant alloy
Sanicro 67 N06690 - 2.4642 -
Sanicro 38 N08825 Mod. - 2.4858 -
Sanicro 30 N08800 - 1.4558 -
Sanicro 28 N08028 - 1.4563 X1NiCrMoCu31-27-4
Sandvik 3RE28 - 310 1.4845* -
Sandvik 3R12 S30403/
S30400
304L 1.4306 -
Load carrying alloy
4L7 - SA210-A1 1.0425 ST45.8/lll
3Mo1 - - 1.5415 16Mo3
HT5 - SA213-T12 1.7335 13CrMo4-5
HT8 - SA213-T22 1.7380 10CrMo910
HT7 - SA213-T91 1.4903 X10CrMoVNb91
T23 - SA213-T23 1.8201
T24 - SA213-T24 1.7378

* 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).

Size range for composite tube
Outside diameterTotal minimum
wall thickness
Thickness
outer layer
Minimum thickness
inner layer
mmin.mmin.mmin.mmin.
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