U-bend tubes are widely used in heat-exchanger systems. Heat-exchanger equipment on the basis of seamless stainless U-tubes is essential in strategically important and critical fields — nuclear and petrochemical machine building.
A tube-bending line, that was installed at our factory in the end of 2005, allows to produce U-tubes
as per such standards : 1. ASTM A688/A688M
2. ASTM A803/A803M
3. ASTM A556/A556M, ASME SA-556
4. ASME SA-179/SA213
Technical requirements
Straight tubes for bending:
ASTM/ASME SA 179; SA 213; ASTM B 163; ASTM B 729; ASTM B 407; ASTM B 423; ASTM A 789
U-bend Tubes:
-TEMA RCB 2.31 Standards of the Tubular Exchanger Manufacturers Association (9th edition).
-ASTM A688 Standard specification for welded tubes of austenite corrosion resistant steel grade designed for feed water boilers.
-ASTM B163 Standard technical requirements for tubes of nickel and nickel alloy for condensers and heat exchangers.
-Customer specifications
BENDING RADIUS: from 1.5 OD to 1250 mm.
When ordering tubes with R≤1.5D it is necessary to agree precision of geometrics.
STRAIGHT TUBES MAXIMUM LENGTH (before bending): 26000 mm.
LEG LENGTH: min 1 meter, max 10.5 meters (for max R=1250 mm)
Note: other sizes are available upon agreement.
HEAT TREATMENT: Stress Relieved after U bending.
HYDROSTATIC TEST: maximum test pressure 600 bar, soaking 10 sec. with demineralized water. Compressed air cleaning after hydro-test.
Marking: before bending by marking machine all over the tube length (bent section after heat treatment without marking).
Marking is also possible after bending on the straight parts of U-bent tube.