What Is ASTM B111 C70600 (CuNi 90/10)?
UNS C70600 is the 90/10 copper-nickel alloy, widely identified as CuNi 90/10 or by the German-style designation CuNi10Fe1Mn. It contains nominally 90% copper and 10% nickel, with deliberate iron and manganese additions that strengthen the protective surface film and markedly improve resistance to seawater corrosion, erosion and impingement attack.
Under ASTM B111, C70600 is produced as seamless condenser and heat-exchanger tubes, and is used in power-plant surface condensers, marine cooling systems, desalination evaporators, offshore platforms and petrochemical heat exchangers. The alloy also exhibits strong resistance to biofouling: copper ions released at the surface deter barnacle and mussel attachment, which reduces cleaning and maintenance in seawater service.
ASTM B111 in Brief
ASTM B111/B111M is the standard specification for seamless copper and copper-alloy condenser tubes and ferrule stock for surface condensers, evaporators and heat exchangers. It defines temper states (annealed O61, light-drawn H55, hard-drawn H80 and hard-drawn-and-end-annealed HR50), dimensional tolerances and the required test programme:
Tension test - tensile, yield and elongation verification.
Expansion and flattening tests - ductility and resistance to cracking.
Hydrostatic or pneumatic (air-under-water) test - pressure integrity.
Eddy-current test - surface and near-surface flaw detection (when specified).
Ammonia-vapor (residual-stress) test - susceptibility to stress-corrosion cracking (when specified).
Chemical Composition (ASTM B111 / CDA)
| Element | Composition (%) | Remarks |
|---|---|---|
| Copper (Cu) | Balance | Nominal ≈88%; Cu + sum of named elements ≥99.5% min |
| Nickel (Ni) | 9.0 – 11.0 | Ni value includes Co |
| Iron (Fe) | 1.0 – 1.8 | Both minimum and maximum apply |
| Manganese (Mn) | ≤ 1.0 | - |
| Zinc (Zn) | ≤ 1.0 | - |
| Lead (Pb) | ≤ 0.05 | - |
Mechanical Properties
Minimum requirements for annealed (O61) tube per ASTM B111, with typical annealed-tube values from the CDA:
| Property | ASTM B111 O61 (minimum) | Typical (CDA, annealed tube) |
|---|---|---|
| Tensile strength | 38 ksi (262 MPa) | ≈44 ksi (303 MPa) |
| Yield strength (0.5% ext.) | 15 ksi (103 MPa) | ≈16 ksi (110 MPa) |
| Elongation | 30% | ≈42% |
Light-drawn (H55) and hard-drawn (H80) tempers provide higher strength with reduced ductility; the required temper should be selected with the design stress and forming sequence in mind.
Physical Properties
| Property | Value (CDA, at 68°F / 20°C) |
|---|---|
| Density | 0.323 lb/in³ (8.94 g/cm³) |
| Thermal conductivity | 26 BTU·ft/(ft²·h·°F) ≈ 45 W/(m·K) |
| Electrical conductivity | 9% IACS |
| Modulus of elasticity (tension) | 18,000 ksi (≈124 GPa) |
| Melting range | 2010 – 2100 °F (≈1099 – 1149 °C) |
| Coefficient of thermal expansion | 9.5 × 10⁻⁶ /°F (68–572 °F) |
International Equivalent Grades
| Country | Standard | Equivalent Grade |
|---|---|---|
| USA | ASTM B111 | C70600 |
| United Kingdom | BS | CN102 |
| Germany | DIN 1785 | CuNi10Fe1Mn |
| Japan | JIS H3300 | C7060 |
| China | GB/T 8890 | BFe10-1-1 |
| Europe | EN 12451 / EN 12449 | CW352H |
Equivalent grades are composition- and form-comparable, but the governing standard for each market should always be confirmed before specification.
Corrosion Resistance and Seawater Performance
C70600 is engineered for seawater. Its corrosion behaviour is characterised by:
Uniform corrosion: very low rates in clean, flowing seawater; the alloy tolerates brackish water and moderate pollution.
Impingement and erosion resistance: the iron-manganese strengthened surface film resists impingement attack at design velocities.
Biofouling resistance: copper-ion release prevents barnacle, mussel and algal attachment, reducing cleaning cycles.
Stress-corrosion resistance: essentially immune to chloride stress-corrosion cracking in marine service, unlike many stainless steels.
Flow velocity. Industry guidance (CDA / Nickel Institute) puts the practical design velocity for C70600 at roughly 2.5–3.5 m/s in seawater, with critical velocities of about 3.7 m/s (12 ft/s) reported in clean seawater. Above these levels, or where severe impingement is expected, the higher-strength 70/30 alloy C71500 is normally specified.
Compared with 304/316 stainless steel: in full seawater service CuNi 90/10 generally offers superior resistance to chloride pitting and crevice corrosion and better thermal conductivity, with a proven service record in condensers and desalination plant. (See CDA guidance; final selection should always be validated against the specific water chemistry.)
C70600 (90/10) vs C71500 (70/30)
| Property | C70600 (90/10 CuNi) | C71500 (70/30 CuNi) |
|---|---|---|
| Nickel content | 9.0 – 11.0% | 29.0 – 33.0% |
| Copper content | Balance (≈88%) | Balance (≈68%) |
| Tensile strength (annealed, min / typical) | 38 ksi min; ≈44 ksi typ. | ≈54–60 ksi typ. (CDA) |
| Seawater corrosion | Excellent | Superior |
| Erosion / impingement resistance | Good | Excellent at high velocity |
| Thermal conductivity | ≈45 W/(m·K) (CDA) | ≈29 W/(m·K) (CDA) |
| Relative cost | Lower | Higher |
| Typical application | General seawater cooling, condensers, desalination | High-velocity seawater, impingement-prone locations |
Applications
Power plants: surface condensers, turbine cooling systems, boiler heat exchangers.
Marine and offshore: ship condensers, marine air coolers, offshore platform cooling systems.
Petrochemical: oil-refinery heat exchangers, chemical-plant cooling systems.
Desalination: seawater evaporators, distillers, brine heaters (also covered by ASTM B552 for desalting plants).
Other heat transfer: steam-turbine auxiliaries, HVAC systems, shell-and-tube heat exchangers.
Packaging – How We Ship C70600 Without Damage
Our packing rules for C70600:
Tubes: capped both ends + foam wrap + wooden spool or woven bag
Plates/sheets: anti-rust paper + plywood crate
Rods/bars: VCI film + fumigation-free case
Wire: spooled + pallet wrapped
Strip: interleaved paper + carton or coil box
All C70600 packaging includes:
Moisture barrier
Edge protection (where needed)
Clear labeling (grade, heat, size, PO number)
We pack for sea freight, air freight, or warehouse storage.
Factory – What We Use to Make C70600 Right
What we use for C70600:
Horizontal caster (billet control)
Reverse extrusion press (seamless starts here)
Cold pilger & draw benches (tube precision)
Roller leveler & slitter (plate/strip)
Annealing furnace (consistent temper)
Pickling line (clean surface)
What we don't do: mix scrap, skip heat treatment, fake test reports.
Result: C70600 that actually meets ASTM B151 / ASME SB151.
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Manufacturing and Quality Assurance at GNEE
GNEE (Henan Gnee New Material Co., Ltd.) supplies ASTM B111 C70600 seamless tubes produced by hot extrusion followed by cold drawing and final annealing. Supply highlights:
Outer diameters from 4 mm to 419 mm, lengths up to 12 m (custom sizes on request).
100% eddy-current testing plus hydrostatic and chemical/mechanical verification.
EN 10204 3.1 mill test certificates (MTC) as standard.
Third-party inspection available (SGS, TÜV, DNV, Lloyd's, ABS) on request.
Seaworthy export packaging: tube ends capped, foam-wrapped, in wooden spools or woven bags; clear labelling of grade, heat, size and PO number.
Note: the size range and inspection programme above are GNEE commercial commitments stated on this page; verify against the final quotation and MTC for each order.
FAQ
Q1. What is the difference between ASTM B111 and ASTM B466 C70600 tubes?
ASTM B111 covers seamless copper and copper-alloy condenser tubes and ferrule stock for heat-transfer equipment and includes ductility and residual-stress tests. ASTM B466 covers seamless copper-nickel pipe and tube for general fluid transport. For condenser and heat-exchanger duty, specify B111.
Q2. What are the international equivalent grades of ASTM B111 C70600?
BS CN102 (UK), DIN CuNi10Fe1Mn per DIN 1785 (Germany), JIS C7060 per JIS H3300 (Japan), GB BFe10-1-1 per GB/T 8890 (China) and EN CW352H per EN 12451/12449 (Europe).
Q3. What are the minimum mechanical properties of annealed (O61) C70600 tube per ASTM B111?
Minimum tensile strength 38 ksi (262 MPa), minimum yield strength 15 ksi (103 MPa) and minimum elongation 30%. Typical annealed-tube values per CDA are about 44 ksi and 42% elongation.
Q4. What is the chemical composition of C70600?
Copper balance, nickel 9.0–11.0%, iron 1.0–1.8%, manganese ≤1.0%, zinc ≤1.0% and lead ≤0.05%, per ASTM B111 and the CDA alloy database.
Q5. Can C70600 be used for high-velocity seawater?
C70600 suits seawater velocities of roughly 2.5–3.5 m/s, up to about 3.7 m/s (12 ft/s) in clean seawater. For higher velocities or severe impingement, C71500 (CuNi 70/30) is normally recommended.
Q6. What tests are required for ASTM B111 C70600 condenser tubes?
Typical requirements include tension, expansion, flattening, hydrostatic (or pneumatic/air-under-water) and, when specified, eddy-current and ammonia-vapor residual-stress tests. GNEE supplies 100% eddy-current tested tubes with an EN 10204 3.1 MTC.
