ASTM B111/ ASME SB111 C70600 Copper Alloy Seamless Tube for Shell & Tube Heat Exchanger and Condenser
Yuhong Group Co., Ltd. supplies ASME SB111 UNS C70600 seamless copper-nickel tubes alongside complementary heat exchanger components—including tube sheets, baffle plates, U-bend tube bundles, finned tubes, and channel covers—for shell-and-tube heat exchangers, pressure vessels, and air-cooled heat exchangers. All products are manufactured and documented to ASME Section VIII, TEMA, and API standards with full mill test certification.
Product Overview
ASTM B111/ASME SB111 UNS C70600 seamless tubes—commonly referred to as 90/10 copper-nickel or CuNi10Fe1Mn—are seamless condenser and heat exchanger tubes manufactured to ASME SB111 (equivalent to ASTM B111). The specification covers seamless tube and ferrule stock up to 3⅛ in. (80 mm) outside diameter for use in surface condensers, evaporators, and heat exchangers. C70600 (90% copper, 10% nickel with controlled iron and manganese additions) provides excellent resistance to seawater corrosion, biofouling, and stress corrosion cracking.
Specifications & Dimensions
| Parameter |
Specification |
| Standard |
ASME SB111 (ASTM B111) |
| Alloy / UNS |
C70600 / CuNi10Fe1Mn / МНЖМц10-1-1 |
| Temper |
O61 (Annealed) |
| Outside Diameter |
¼″ to 4½″ (6.35 mm to 114.3 mm) |
| Wall Thickness |
25 BWG to 10 BWG (0.508 mm to 3.4 mm) |
| Length |
Up to 18 m or custom cut |
| End Finish |
Plain, beveled, or threaded |
Chemical Composition (ASME SB111 C70600)
| Element |
Content (%) |
| Copper (Cu) |
Remainder (min 88.6%) |
| Nickel (Ni) + Cobalt (Co) |
9.0 - 11.0 |
| Iron (Fe) |
1.0 - 1.8 |
| Manganese (Mn) |
1.0 max |
| Lead (Pb) |
0.05 max |
| Zinc (Zn) |
1.0 max |
Iron content between 1.0% and 1.8% is critical for forming a stable protective oxide film in seawater service.
Mechanical Properties (O61 Annealed Temper)
| Property |
Value |
| Tensile Strength, min |
38 - 40 ksi (260 - 275 MPa) |
| Yield Strength, min |
13 - 15 ksi (90 - 105 MPa) |
| Elongation (in 2″ or 50 mm), min |
30% |
| Density |
8.94 g/cm³ |
| Thermal Conductivity |
40 W/mK @ 20°C |
| Annealing Temperature |
593 - 816°C (1100 - 1500°F) |
Testing & Quality Assurance
All tubes are subjected to the following tests per ASME SB111 Clause 19:
| Test Method |
Requirement |
| Eddy Current Test (ECT) |
100% of tubes, per ASME SB111 Clause 13.1.1 |
| Hydrostatic Test |
Per ASME SB111 Clause 13.1.2, or Pneumatic Test per Clause 13.1.3 |
| Flattening Test |
Specimen flattened per ASME SB111 |
| Expansion Test |
Per temper designation |
| Mercurous Nitrate Test |
Per ASME SB111 |
| Ammonia Vapor Test |
Per ASME SB111 |
| Tensile Testing |
Per ASME SB111 |
| Chemical Analysis |
Mill test certificate (MTR) per EN 10204 3.1/3.2 |
Applications
ASME SB111 C70600 seamless tubes are specified for shell-and-tube heat exchangers and condensers in:
- Power Generation: Main condensers, cooling water systems, feedwater heaters
- Marine & Shipbuilding: Seawater cooling systems, auxiliary condensers, oil coolers
- Desalination Plants: Brine heaters, heat recovery sections, evaporators
- Chemical & Petrochemical: Process heat exchangers, coolers
- Offshore: Fire water systems, seawater piping
- HVAC & Refrigeration: Condensers, evaporators
Technical Advantages
Corrosion Resistance in Seawater
C70600 develops a protective corrosion product film when wetted in clean oxygenated seawater. The controlled iron content (1.0-1.8%) stabilizes this film against localized attack and pitting. Maximum recommended seawater flow velocity is 3.0 m/s.
Biofouling Resistance
Copper-nickel alloys release copper ions that inhibit macro-fouling attachment. C70600 tubes require significantly less frequent cleaning than non-fouling-resistant materials such as titanium.
Fabricability
C70600 is suitable for soldering, brazing, gas-shielded arc welding, and butt welding. For welded joints, AWS A5.7 ERCuNi filler metal must be used—pure copper filler causes galvanic corrosion.
Customization Services
Yuhong Group provides:
- Straight-length and U-bend tubes
- Custom tube diameters, wall thicknesses, and lengths
- Complete tube bundles with tube sheets, baffles, tie-rods, and spacers
- Low-fin integral tubes for enhanced heat transfer
- Third-party inspection (ABS, BV, DNV, GL, CCS)
Frequently Asked Questions
Q: What is the most common cause of C70600 tube failure?
Low iron content below the ASME SB111 minimum of 1.0%. Uncertified suppliers may use less nickel and iron to reduce cost, preventing formation of the protective oxide film and leading to pitting within months. Always verify iron content on the mill test certificate.
Q: What is the maximum seawater flow velocity for C70600 tubes?
C70600 provides reliable corrosion resistance at flow velocities up to 3.0 m/s. Above 3.5 m/s, the protective film wears away mechanically. Inlet end inserts are recommended for applications with velocity spikes during pump startup.
Q: Can C70600 tubes be used in brackish water?
Yes. C70600 performs well in brackish water and chloride-containing cooling media. However, hydrogen sulfide (H₂S) and ammonia (NH₃) accelerate corrosion and should be monitored.
Q: What is the difference between C70600 and C71500 for condenser tubes?
C70600 (90/10 Cu-Ni) has slightly lower strength but better thermal conductivity and is more cost-effective. C71500 (70/30 Cu-Ni) offers higher strength and erosion resistance for more demanding seawater applications.
Q: What welding filler should be used with C70600?
AWS A5.7 ERCuNi filler metal matching C70600 composition. Pure copper filler creates a galvanic couple and accelerates corrosion at the weld joint.
