U Bend Stainless Steel Tubes are manufactured in our plant as per the customer requirements. Bends can be Heat Treated in accordance with Clients’ requirements followed by hydrostatic testing and dye penetrant testing if required.
U bend tubes are widely used in heat-exchanger systems. Heat exchanger equipment on the basis of stainless U-tube is essential in strategically important and critical fields nuclear and petrochemical machine building.
U tubes heat exchangers Designed for high temperature applications, especially steam condensing or hot oil systems. Thïs model is selected when differential expansion makes a fixed tube sheet exchanger unsuitable and when conditions preclude a floating head type (HPF) selection.
Surface condition Finished U-tubes shall be free of scale, without scratches after bending.
Dimensional tolerances U tubes acc. to TEMA R.C.B.
Length of straight part -0/+5 mm
Flattening (also called “ovality”) at the bend shall not exceed 10% of the nominal tube outside diameter.
Wall thickness in bending part acc. to TEMA RCB 2.31 Minimum tube wall thickness in the bend part (T min)T(min) ≥ (SW × (2×R + D))/( 2× (R+D)where:
SW is smallest wall thickness D Nominal outside diameter R radius
Radius tolerance 1) for R 100 mm +/- 3 mm
2) for R ≥ 100 mm +/- 5 mm
Straightness tolerance max. 1,5 mm per 1 m
U-Tubes ends: plain, vertically cut to the tube axis
Tube-bending line, installed at 2007, will allow to produce U-tubes as per such standards:
1. ASTM A688/A688M-08
2. ASTM A803/A803M
3. ASTM A556/A556M, ASME SA556
4. ASME SA-688
Maximum lengths of 27000mm can be supplied on request
Tubes OD in mm can be bent upon agreement: 15,8 – 16,0 – 17,0 – 18,0 – 19,05 – 20,0 – 21,3 – 25,4 -26,7 – 31,8 -38,1
Maximum: 1500 mm
Heat treatment of the bend
U bend tubes with a bending radius up to maximum of 1500mm can be heat treated on request
The basic Testing and processing:
1. High Pressure Hydrostatic Test:Minimum:10 Mpa-25Mpa.
2. Air Under Water Test After Bending
3. U Tubes Wall Thickness Test
4. Eddy Current Test before U bend Formed
5. Ultrasonic Test before U bend Formed
6. Heat treatment to stress relieved
7. Ball passing test
The below sizes are those most frequently used,other sizes can be produced upon request.
The dimensions for heat exchanger tubes in special grades may differ from the above,please contact us: email@example.com .
|Grade(UNS):|| Austenitic Stainless Steel:|
304/304L/304H(1.4301/1.4306/1.4948); 316/316L(1.4401/1.4404); 316Ti(1.4571);
321(1.4541);309S (1.4833); 310S(1.4845); 317L(1.4438)321H(1.4878); 347H (1.4550);
Duplex Stainless Steel:
|Outside Diameter:||6 – 830mm|
|Wall Thickness:||0.50 – 60mm|
|Standards(Norm):||EN 10216-5; DIN 17456, DIN 17458, DIN 2462, DIN 17455|
|GB/T14975; T14976; T13296; GB5310;|
|ASTM A213, A269, A312, A511, A789, A790, A928, A999, A1016, ASTM B161, ASTM B163, ASTM B165, ASTM B167, ASTM B338, ASTM B407, ASTM B423, ASTM B444,ASTM B619, ASTM B622, ASTM B626, ASTM B668, ASTM B677, ASTM B829|
|JIS G3459, JIS G3463, JIS G3446, JIS G3447, JIS G3448, JIS G3468|
|GOST 9940;GOST 9941;|
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)