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The semi-finished product for U bend tubes are heat exchanger tubes, manufactured and supplied according to DIN 28180 and ASTM A179.
Chemical Composition and Mechanical Properties (Part)
| Standard | Grade | Chemical Components (%) | Mechanical Properties | ||||||||||
| C | Si | Mn | P | S | Mo | Cr | V | T.S. (Mpa) | Y.S. (Mpa) | E.L. (%) | Hardness (HRB) | ||
| ASME SA179 | SA179 | 0.06-0.18 | / | 0.27-0.63 | ≤0.035 | ≤0.035 | / | / | / | ≥325 | ≥180 | ≥35 | ≤72 |
| ASME SA192 | SA192 | 0.06-0.18 | ≤0.25 | 0.27-0.63 | ≤0.035 | ≤0.035 | / | / | / | ≥325 | ≥180 | ≥35 | ≤77 |
| ASME SA210 | A1 | ≤0.27 | ≥0.10 | ≤0.93 | ≤0.035 | ≤0.035 | / | / | / | ≥415 | ≥255 | ≥30 | ≤79 |
| C | ≤0.35 | ≥0.10 | 0.29-1.06 | ≤0.035 | ≤0.035 | / | / | / | ≥485 | ≥275 | ≥30 | ≤89 | |
| ASTM A333 /A334 | GR.1 | ≤0.30 | / | 0.4-1.06 | ≤0.025 | ≤0.025 | / | / | / | ≥380 | ≥205 | ≥35 | -45° |
| GR.6 | ≤0.30 | ≥0.10 | 0.29-1.06 | ≤0.025 | ≤0.025 | / | / | / | ≥415 | ≥240 | ≥30 | -45° | |
| GR.8 | ≤0.13 | 0.13-0.32 | ≤0.90 | ≤0.025 | ≤0.025 | / | / | 8.40-9.60 | ≥690 | ≥515 | ≥22 | -195° | |
U bend tubes for heat exchangers applied mostly in oil and gas plants, chemical and petrochemical plants, refineries, power plants and renewable energy plants. Low fin tubes can be supplied in the form of U bends.
U-Bend Fabrication Tolerances
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
| Item | Condition (when) | Tolercance |
|---|---|---|
| Ovality | Nominal bend radius ≤ 2 x nominal OD | less than or equal to 12% |
| 2 x nominal OD < Nominal bend radius ≤ 4 x nominal OD | less than or equal to 10% | |
| Nominal bend radius > 4 x nominal OD | less than or equal to 5% | |
| Nominal bend radius ≤ 2 x nominal OD | 0.75 x nominal wall | |
| Mimimum wall thickness | 2 x nominal OD < Nominal bend radius ≤ 4 x nominal OD | 0.8 x nominal wall |
| Nominal bend radius > 4 x nominal OD | 0.9 x nominal wall | |
| Nominal bend radius ≤ 8" (200mm) | +/-3/64"(1mm) | |
| Bending Radius | 8" (200mm) < Nominal bend radius ≤ 16" (400mm) | +/-1/16"(1mm) |
| Nominal bend radius >16" (400mm) | +/-5/64"(1mm) | |
| Disrance between legs | Max 1/16"(1.5mm) | |
| Wall thinning of bending area | Max 17% | |
| Difference between leg lengths at the ends | Leg length ≤ 16' (4.88m) | +1/8"(3mm) |
| Leg length > 16' (4.88m) | +3/16"(5mm) | |
| Deviation from plane of bend | ≤ 3/16"(1.5mm) | |
| Flattening on bend | ≤ 10% nominal diameter | |
| Straight leg length | ≤5m | +1/8"(3mm) |
| >5m | +3/16(5mm) | |
| Total tube length including radius | ≤6m | +3/16(5mm) |
| >6m | +5/16"(8mm) |
Material
'U' bends are produced, controlled and measured fully in accordance with relevant standards
| Material | Grade |
| Carbon Steel | SA 179 / A 179 |
| Carbon Steel | SA 210 / A 210 |
| Carbon Steel | SA 334 / A 334 |
| Stainless Steel | SA 213 / A 213 |
| Duplex Stainless Steel | SA 789 / A 789 |
Applications
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.
"U bend tubes for heat exchangers applied mostly in Oil & Gas plants, Chemical & Petrochemical plants, Refineries, Power plants, Renewable energy plants."
- Object medium: 10% sodium
- hydroxide+5% sodium hypochlorite
- Shell Diameter: ø 800
- Working Pressure: 1.5mpa
- Working Temperature: 40º C-90º C
- Heat Exchange Surface Area: 100M2
- Material: Gr1\Gr2
Fin tubes
Fin tubes are used in applications involving the transfer of heat from a hot fluid to a colder fluid through a tube wall. Furthermore, finned tubes are used when the heat transfer coefficient on the outside of the tubes is appreciably lower than that on the inside.
