"U" bent tubes for heat exchangers can be supplied in accordance ASME SA556, ASME SA179, ASME SA192, ASME SA213, ASME SA688, ASME SA803
Reference standards and Steel Grades: 304/304L Austenitic, 316/316L Austenitic, 2205 Duplex, 2507 Duplex,439 Ferritic
ASTM A556 Gr. A2 - B2 - C2, ASME SA556 Sect.II Gr. A2 - B2 - C2
"U" Bent tubes in accordance with the standards detailed in table 1, part A can be requested.
The bent area can be subject to stress relieving heat treatment by joule effect in inert atmosphere.
- Minimum radius treated = 28 mm.
- Maximum radius treated = 750 mm.
2. U bend Tube Bundle Dimensions and lengths
Tubes with the following external diameters in mm can be bent a upon agreement: 15,8 - 16,0 - 17,0 - 18,0 - 19,05 - 20,0 - 21,3 - 25,4 - 26,7 - 31,8 -38,1.
The minimum feasible radius is : 1,5 x external diameter
The maximum feasible radius is 1500 mm.
A556 U bend Tube
3. U bend Tube Bundle Tolerances
Tolerances (diameter and wall thickness) according to ASTM A 556 or given in the standards detailed in table 1 point A are respected.
Bending tolerances. The tolerances stipulated in ASTM A 556 are respected.
Minimum wall thickness tolerances in the bent area conforming to the TEMA standard "Class R heat exchangers" can be requested or in accordance with specific requests.
4. U bend Tube Bundle Checks and test
All the mechanical and technological tests stipulated in the cited standards are carried out.
Leak tightness test: electromagnetic test (Eddy Current) is performed on straight tubes. Hydrostatic test on bent tubes is performed only if expressly requested, specifying the test pressure
5. U bend Tube Bundle Standard Technical Range
OD 9.5mm - 38.1mm
WT up to 6.35mm
Bending radii 1.25 x OD up to 1700mm
Bends can be supplied in accordance with TEMA R / ASTM SA/A556
Leg length up to 15000mm
6. U bend Tube Bundle Test
Heat treatment where required by electric furnance or direct resistance
Hydrotesting up to 10,000 psi https://www.lordfintube.com/ |