High-temperature Stainless Steel Tubes For Superior Performance
Sa-213 tp347h u-bend tubes offer exceptional corrosion resistance and high-temperature strength for heat exchangers and boilers.
High-temperature Stainless Steel Tubes For Superior Performance
Sa-213 tp347h u-bend tubes offer exceptional corrosion resistance and high-temperature strength for heat exchangers and boilers.
SA-213 TP347H U-Bend Tubes are seamless austenitic stainless steel tubes designed for high-temperature and high-pressure applications in heat exchanger tubes, superheaters, and boilers. Conforming to ASME SA-213 and ASTM A213 specifications, these high-temperature tubing solutions are engineered for industries such as petrochemical, power generation, and chemical processing, where corrosion resistance and pipeline durability are critical. The U-bend design facilitates compact layouts and acts as a thermal expansion absorber, reducing stress in piping systems.
The SA-213 TP347H U-Bend Tubes are made from a stabilized austenitic stainless steel alloy containing niobium (columbium) and a higher carbon content than TP347, enhancing creep strength and intergranular corrosion resistance. Available in outer diameters from 6.35mm to 50.8mm, wall thicknesses from 0.8mm to 3.4mm, and bend radii from 1.5D to 1500mm, these tubes are customizable for leg lengths up to 16.5 meters. They are manufactured via cold-drawing or hot-rolling, followed by solution annealing at 1010-1193°C (1850-2000°F) and water quenching to optimize mechanical properties and ensure corrosion resistance.
These U-shaped tubing solutions undergo rigorous testing, including hydrostatic, eddy current, flaring, flattening, and positive material identification (PMI) tests, to ensure compliance with ASME SA213/A213M standards. The high chromium (17.0-19.0%) and nickel (9.0-13.0%) content, combined with niobium (up to 1.0%), provides excellent resistance to oxidation and corrosion in harsh environments, such as those involving sulfuric acids or high-temperature steam. Surface treatments like pickling, passivation, or bright annealing enhance durability, while capped ends prevent contamination during transport and installation.
The SA-213 TP347H U-Bend Tubes are particularly suited for ultra-supercritical (USC) coal boilers and reheaters, operating at temperatures up to 650°C for pressure parts and 850°C for oxidation-resistant components. Their stabilized composition prevents carbide precipitation, ensuring reliability in applications like oil and gas pipelines, where hydrogen sulfide corrosion is a concern. Compared to TP304H, TP347H offers superior creep strength and weldability, with no need for preheating or post-weld heat treatment in most cases, simplifying installation.
In demanding environments, the SA-213 TP347H U-Bend Tubes minimize pipeline wear, thermal stress, and corrosion, ensuring long-term performance and safety. Their ability to handle high temperatures and pressures, combined with low maintenance and compatibility with complex heat exchanger designs, makes them a preferred choice for engineers seeking reliable heat exchanger tubes for critical applications.
SA 213 TP347H tubes are available in many shapes, including round, square, hollow, rectangular, hydraulic, coiled, straight, and "U" shape. The tubing sizes and thicknesses are usually 1/8 in. or 3.2 mm and inside diameter of 5 inch. The minimum wall thickness is 0.015 to 0.500 inch.
Engineered to meet diverse industrial needs with robust materials and versatile designs.
347H is the higher carbon version of 347 plate. Due to the additional carbon present in 347H plate, it is tougher and generally more durable than 347 plate. These grades of stainless steel plate is available in a wide range of sizes at Penn Stainless Products.
This grade of stainless steel has an elongation of 40%. On the Brinell hardness scale 347 and 347H stainless steel plate has hardness of 201 and on the Rockwell B scale, both 347 and 347H have a hardness of 95.
| Element | Content Range (%) |
|---|---|
| Carbon (C) | 0.04–0.10 |
| Manganese (Mn) | ≤2.00 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.045 |
| Sulfur (S) | ≤0.030 |
| Chromium (Cr) | 17.0–19.0 |
| Nickel (Ni) | 9.0–13.0 |
| Niobium (Nb) | 8×C–1.10 |
Note: Niobium is added for stabilization to reduce carbide precipitation and enhance resistance to intergranular corrosion.
| Property | Value | |
|---|---|---|
| Tensile Strength, min | ≥515 MPa (≥75 ksi) | |
| Yield Strength (0.2% offset), min | ≥205 MPa (≥30 ksi) | |
| Elongation (in 50 mm), min | ≥35% | |
| Hardness (Brinell, HBW), max | 201 | |
| Hardness (Rockwell B, HRB), max | 95 |
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ |
| Melting Range | 1400–1450°C (2552–2642°F) |
| Thermal Expansion Coefficient (20–100°C) | 16.6 μm/m·°C |
| Thermal Conductivity (100°C) | 15 W/m·K |
| Specific Heat Capacity (20°C) | 500 J/kg·K |
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...................The difference in length between two straight pipe
sections
c..............The tangent spacing of the outer wall of the elbow
Da............nominal steel pipe outer diameter
E..............The distance between the outer diameters of the two straight
ends
f...............the distance between the ends of the two straight ends
l............... straight tube length
Lg............. straight pipe section plus total length of pipe
Rm...........nominal bending radius
S.............nominal wall thickness
Smin.......The minimum wall thickness at the back of the elbow
t...............the bend deviates from the horizontal distance
So...........Standard minimum wall thickness
| Item | Condition (when) | Tolerance |
|---|---|---|
| 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 | |
| Minimum 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) | |
| Distance 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) |
U-Tube heat exchangers are known for their distinctive U-shaped tubes that offer several advantages and also come with certain limitations.
The U-tube heat exchanger features a single tubesheet with both ends of the tubes secured to it. This design allows the tubes to expand and contract freely, avoiding thermal stress and offering excellent thermal compensation. A double tube pass is utilized, providing a lengthy process path, high flow rates, and superior heat transfer performance with robust pressure resistance. The tube bundle is removable from the shell for convenient maintenance and cleaning, presenting a simple structure and low cost.
Limitations imposed by the elbow's curvature radius restrict the arrangement of heat exchange tubes. This results in a larger inner tube spacing within the tube bundle and a lower utilization rate of the tube sheet. The shell-side fluid is prone to short-circuiting, which can impede heat transfer. When a tube leaks or sustains damage, only the U-shaped tubes on the outer part of the bundle can be readily replaced. Damage to the inner heat exchange tubes is not as easily repairable and may require blocking off. Furthermore, the damage to a single U-shaped tube equates to the loss of two tubes, leading to a higher scrap rate.
U-bend tubes are used to transfer heat between fluids.
Transfers heat between fluids, allowing return flow at 180° in a compact space.
Used in heat exchangers, chemical & petrochemical, food processing, and refrigeration industries.
Applied in heat exchangers at Oil & Gas, petrochemical plants, refineries, and power plants.
Handles aggressive fluids like sodium hydroxide + sodium hypochlorite safely.
Allows pipeline expansion without buckling; flexible or sliding options available.
Enhances heat transfer when the outside coefficient is lower than the inside, improving efficiency.
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