ASTM A688 TP304 Stainless Steel U Bend Tube for Heat Exchanger
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ASTM A688 specification covers the standard requirements for welded austenitic stainless steel feedwater heater tubes, including bent tubes used in tubular feedwater heaters. U-bend tubes are a design adopted in many heat exchangers; they are intended to maximize the surface area and achieve efficient heat transfer in a compact design, and are commonly used in applications such as condensers and petrochemical processes.
ASTM A688 TP304 stainless steel U-bend tubes supplied by GNEE are specialized tubes for heat exchangers, characterized by compliance with the ASTM A688 specification (which defines requirements for seamless and welded stainless steel feedwater heater tubes). All finished tubes or straight tubes prepared for bending into U-shapes shall be supplied in the solution-annealed condition. Before leaving the factory, TP304 stainless steel U-bend tubes also undergo mechanical tests, such as tensile tests, hardness tests, reverse bending tests, flattening tests, flange tests, pressure tests, hydrostatic tests, and underwater air tests. Each sample tube shall be subjected to non-destructive testing (electrical testing), and its corrosion resistance shall be determined.
ASTM A688 TP304 Stainless Steel U Bend Tube for Heat Exchanger Specifications
Straight length:max 30000 mm
Leg length:12000 mm, points of tangency of the bend to the leg end
Bending radius:max 1500 mm
Manufacturing method:TIG welding, Cold drawn
Finishes: Annealing Pickling (AP), Bright Annealed (BA)
Straight length equal to 2 x leg length + 3.1416 x R
Heat treatment shall be applied to the U-bend area plus approximately 6 in. [150 mm] of each leg beyond the tangent point of the U-bend after bending, if specified.
Email: info@gneestainless.com
ASTM A688 TP304 Stainless Steel pipe Chemical Composition
| Elem-Ent | Grade | TP304 | TP304L | TP304LN | TP 304N |
|---|---|---|---|---|---|
| % | UNS | S30400 | S30403 | S30453 | S30451 |
| C, Max | 0.08 | 0.035 | 0.035 | 0.08 | |
| Mn, Max | 2.00 | 2.00 | 2.00 | 2.00 | |
| Ph, Max | 0.040 | 0.040 | 0.040 | 0.040 | |
| S, Max | 0.030 | 0.030 | 0.030 | 0.030 | |
| Si,,Max | 0.75 | 0.75 | 0.75 | 0.75 | |
| Ni | 8.00-11.00 | 8.00-13.00 | 8.00-13.00 | 8.00-1.00 | |
| Cr | 18.00-20.00 | 18.00-20.00 | 18.00-20.00 | 18.00-20.00 | |
| Mo | - | - | - | - | |
| N | - | - | 0.10-0.16 | 0.10-0.16 |
what is ASTM A688 U Bend Stainless Steel Tube Dimensional Tolerance?
ASTM A688 U bend tube tolerance of outside should be accordance with specification A1016/M, the bent portion of U tubes for R =2 X D or greater, tolerance shall deviate from the nominal diameter prior to bending by more than 10 % if less than 2 X D is specified, tolerances could be greater, minimum wall thickness shall not exceed +20 % − 0, average wall thickness are 10 % of the nominal wall thickness, bent area wall tolerance shall not be less than value determined by the equation: 4RT/(4R+D).
GNEE has nearly 18 years of experience producing U-bends for feedwater heaters. We offer welded and seamless pipes in lengths up to 30 meters. The bends are heat-treated, with a maximum bend radius of 1.5 meters and tolerances in accordance with ASTM A688. We package only high-quality pipes and deliver them to customers worldwide.
Grades: 304/304L, 304H, 316/316L, 316H, 317L, 321, 310S (2520), 347H, S31803/S32205, S32750, S32760, S32304, 904L
