Stainless steel U bend tube is widely used for high-temperature or low-temperature conditions, especially in heat exchanger and boiler systems, manufactured standards include ASTM A688 and ASTM A803, and standard stainless steel material has 304 / 304L, 316 / 316L, 321, as duplex S31803, 2205, and nickel alloys.
U bend tubes for heat exchangers are applied mostly in Oil & Gas plants, Chemical & Petrochemical plants, Refineries, Power plants, and Renewable energy plants.
U Bend Tube Specifications
| Straight | Max 30000 Mm |
|---|---|
| Radius | Max 1500 Mm |
| Heat Treatment | 100% |
| Leg Length | Max 12000 Mm |
| Manufacturer | Welded And Seamless |
| Specification | A688, A803 |
| Grades | TP304 TP304L, TP316 / TP316L, TP321, S31803 |
| Surface | Annealing Pickling, Bright Annealing |
| Application | Heat Exchanger, feedwater heater |
U Bend Tube Standards And Grades
U bending tubes are manufactured strictly according to the common heat exchanger standards, inspections are done from material to final product to ensure U bending tubes 100% high quality to meet critical applications.
| StandardS | Grades | Remarks |
|---|---|---|
| ASTM A213, SA213 | T9, T11, T12 304/304L/304H 316/316L/316H,316TI 321/321H 347/347H | Seamless Ferritic and Austenitic Alloy-Steel Boiler, Super heater, and Heat-Exchanger Tubes |
| ASTM A249, SA249 | 304/304L/304H 316/316L/316H,316TI 321 | Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes |
| ASTM A789, SA789 | S31803, S32205, S32750, S32760 | Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing |
| ASTM A268, SA268 | 409, 410, 430, 439 | Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing |
| ASTM A688, A803 | 304/304L 316/316L 439, 446 | Seamless and Welded Austenitic and Ferritic Stainless Steel Feedwater Heater Tubes, |
| ASTM B163, SB163 | Nickel alloys | eamless Nickel and Nickel Alloy Condenser and Heat-Exchanger Tubes |
U Bend Tube Manufacturing and Technology
Tolerances should be controlled to conform to ASTM A688 standard, Special tolerances are available upon customer requirements.
Heat treatment should be done after U bend, heat treatment of the bending portion may be required to reduce the residual stress, if not specified, heat treatment of bends plus minimum 150 mm of the leg is standard.
U bend tubes should be fabricated as standard in high quality, controlling ovalization and thickness of bending portion accurately, and straightness of leg length, squareness and cleanliness of tube ends should be cut, to achieve premium quality u bend tube, some factors and tests must be considered.
- Dimension certificate
- Flaring and flattening
- Hydrostatic test
- U.T test
- Air Underwater Test
- Ovalization of straight and bending portion
- Wall thickness of bending portion
Stainless steel U bend tube is used in heat exchanger systems and other systems, it transfers heat from a hot to a cold side through the tube. This is made possible through the width of the tubes on each end, poor tube material can result in problems.
U Bend Tube Packing
- Ends of tubes protected by plastic caps
- Vertical separators for each radius
- horizontal separators for each tube
- Standard wooden case
U Bend Tube Dimensions
Outside Diameter: 12.7, 14, 15, 16, 19.1, 20, 22, 23, 25.4, 28, 30, 21.8, 34, 36, 38.1 mm
Wall thickness: 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, 1.65, 2.0, 2.11, 2.5, 3.0 mm