ASTM B395 U-Bend Seamless Copper & Copper-Alloy Tubes for Heat Exchangers

Material

ASTM B395/B395M U-bend tubes are 180°-bent, seamless tubes used in condensers, evaporators, and heat exchangers, manufactured from seamless copper and copper-alloy tube. The specification applies to tubes ≤ 2 in. (50 mm) OD and covers common heat-transfer alloys including oxygen-free copper (C10200), phosphorus-deoxidized copper (C12200), admiralty/aluminum brass (C44300/C68700), and copper-nickel grades (C70600/C71500), among others.

Specifications

• Product form: U-bend tube (bent 180° in a single plane into a U-shape).

• Size range (OD): ≤ 2 in. (50 mm).

• Alloy/temper: Per order—UNS designation and temper must be specified.

• Key ordering parameters (recommended to state on PO/drawing):

  • Tube OD × wall thickness

  • Bending radii schedule

  • Leg length (straight legs)

• Dual-gage option (for small bend radius):

  • Dual-gage = tube with more than one wall-gage thickness.

  • If specified, the central section is made one BWG thicker than the straight-leg wall before bending; by default it is made to constant ID (heavier section achieved by increasing OD).

• Bend quality: The bent portion shall be substantially uniform in curvature.

Main Features

• High heat-transfer efficiency from copper/copper-alloy metallurgy (optimized for condenser/evaporator/heat-exchanger service).

• Alloy flexibility: copper, brasses, aluminum brasses, and Cu-Ni grades to match cooling media (freshwater, brackish, seawater).

• Process-ready geometry: accurate U-bends for compact shell-and-tube bundles.

• Quality verification built into the standard: eddy-current NDT and leak testing options.

Our Advantages

1. “Will the U-bend thin, ovalize, or wrinkle?”
   U-bends naturally face bend-related deformation risks (ovality/thinning). Our solution is controlled bending plus the dual-gage option for small radii: the standard allows a heavier-gage central section (one BWG thicker) before bending to improve bend robustness, while keeping constant ID by default.

2. “How do you ensure the tube is defect-free before bending?”
   ASTM B395 requires each tube, prior to bending, to undergo eddy-current testing following ASTM E243 practice—an industry-standard approach to detect discontinuities likely to cause failure.

3. “How do you guarantee leak-tightness?”
   Each U-bend tube must pass a leak test, with the manufacturer allowed to select the method unless otherwise specified:

• Hydrostatic test to fiber stress 7000 psi (48 MPa) (gage pressure need not exceed 1000 psi / 6.9 MPa unless specified), or

• Pneumatic test at ≥ 60 psi (400 kPa) with no leakage indication for 5 s.

4. “What about stress-corrosion cracking (SCC) risk, especially in brass service?”
   SCC can be driven by environment + residual stress; ammonia-related SCC is a known failure mode in brass heat-exchanger service. We mitigate this by offering material selection support, and for Cu-Ni U-bends the standard provides an option to specify relief anneal of the U-bent portion; susceptibility testing options (ammonia vapor / mercurous nitrate) are also addressed in the specification.

5. “Can you provide traceability and documentation for QA/QC?”
   ASTM B395 ordering options include heat identification/traceability, certification, and Mill Test Report (MTR) when required—supporting project documentation and incoming inspection.

Chemical Composition

Mechanical Properties

Execution Standards

• ASTM: ASTM B395/B395M (U-bend seamless copper & copper-alloy heat exchanger and condenser tubes). Related referenced tests include ASTM E243 (eddy current), plus other test methods referenced inside B395.

• EN: EN 12451:2012 (seamless round copper & copper-alloy tubes for heat exchangers/condensers/evaporators/desalination equipment; size scope stated in the standard).

• GOST: GOST 21646-2003 (copper and brass tubes for heat-exchange equipment—technical requirements and acceptance).

• JIS: JIS H3300 (copper and copper-alloy seamless pipes and tubes; commonly used as the JIS basis for condenser/heat-transfer tube supply).

• GB: GB/T 8890-2015 (seamless copper-alloy tubes for heat exchangers) and GB/T 1527-2017 (drawn tube of copper and copper alloys).

Application Fields

Typical industries

• Power generation (steam surface condensers, feedwater heaters)

• Petrochemical & refinery (coolers, condensers)

• Marine & offshore (seawater coolers, central coolers)

• Desalination & water treatment (brine heaters, condensers)

• HVAC & industrial refrigeration (condensers/evaporators)

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.