What is UNS C70600 Copper Nickel Tube (ASTM B111 / ASTM B466)?
UNS C70600 is a 90% copper and 10% nickel alloy with tiny traces of iron and manganese. Copper increases the material's overall strength, while the trace elements improve corrosion resistance. The result is an engineering alloy that offers outstanding corrosion resistance, particularly in marine and saltwater environments.
UNS C70600 tube (ASTM B111 / ASTM B466) provides good strength and creep resistance while being easy to weld and form, with excellent cold and hot working capabilities.
This alloy tube represents an ideal alternative for operating environments where chloride stress corrosion cracking is problematic – environments where stainless steel tubes are unsuitable.
What are the Equivalent Specifications for UNS C70600 Copper Nickel Tube?
GNEE supplies C70600 tube to meet major global standards. The primary specifications are ASTM B111 (heat exchanger tube) and ASTM B466 (seamless pipe).
| Standard | Scope / Equivalent |
|---|---|
| ASTM B111 | Seamless copper alloy tube for heat exchangers and condensers |
| ASTM B466 | Seamless copper-nickel pipe for general piping |
| ASME SB111 | Same as ASTM B111, for ASME code applications |
| ASME SB466 | Same as ASTM B466, for ASME code applications |
| DIN 2.0872 | German equivalent (CuNi10Fe1Mn tube) |
| EN 12449 CW352H | European standard for CuNi10Fe1Mn tube |
| BS 2871 CN102 | British equivalent |
| MIL-T-16420K | Military specification for tube |
Common names for this tube product: 90/10 Cu-Ni tube, CuNi10Fe1Mn seamless tube, ASTM B111 C70600 condenser tube, C70600 seawater pipe.
What is the Biofouling Performance of UNS C70600 Tube?
UNS C70600 tube has excellent resistance to biofouling and marine corrosion.
Biofouling is a common issue in above-sea and subsea scenarios. The following contaminants can attach to tube surfaces:
Algae
Micro-organisms
Small animals (such as barnacles and mussels)
These contaminants can impair a tube's internal flow or external performance. When biofouling occurs inside a tube, it causes:
Reduced flow rate
Increased pumping costs
Under-deposit corrosion (corrosion that develops beneath fouling layers)
The biofouling resistance of C70600 tube also reduces the risk of pitting. However, the material is susceptible to pitting in contaminated water containing hydrogen sulphide (H₂S). This should be considered for specific environments such as stagnant seawater with organic decomposition.
Advantage over stainless steel tube: Unlike 316L stainless steel tube, C70600 tube does not require periodic cleaning or chemical dosing to prevent biofouling in seawater service.
What are the Mechanical Properties of UNS C70600 Tube (ASTM B111)?
Typical properties for C70600 tube in various tempers:
| Property | Annealed (O61) | Light Drawn (H55) | Hard (H80) |
|---|---|---|---|
| Tensile strength (MPa) | 310 – 380 | 380 – 480 | 480 – 550 |
| Yield strength (MPa) | 105 – 170 | 280 – 410 | 410 – 480 |
| Elongation (%) | 42 – 50 | 15 – 25 | 5 – 10 |
| Hardness (Rockwell B) | 40 – 65 | 70 – 80 | 80 – 90 |
Annealed (O61) C70600 tube offers the highest ductility for bending, flaring, and expanding into tube sheets. Hard temper (H80) offers higher strength for straight pipe runs.
What are the Physical Properties of UNS C70600 Tube?
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.94 g/cm³ | 0.323 lb/in³ |
| Melting point range | 1090 – 1125 °C | 1994 – 2057 °F |
| Thermal conductivity | 40 – 50 W/mK | 278 BTU·in/hr·ft²·°F |
| Electrical conductivity | 9% IACS | – |
| Coefficient of thermal expansion (20-300°C) | 17.1 µm/m°C | 9.5 µin/in°F |
| Magnetic permeability | Low (1.01-1.69) | – |
What are the Fabrication Properties of UNS C70600 Tube?
| Property / Process | Rating / Detail |
|---|---|
| Weldability | Excellent – TIG, MIG, coated metal arc, butt, seam, spot |
| Bending | Good – Annealed tube bends easily; use mandrel for tight radii |
| Flaring / Expanding | Excellent – Annealed tube can be flared or rolled into tube sheets |
| Cold forming | Good – Suitable for swaging, reducing, and coiling |
| Hot forming | Good – Recommended temperature: 760-870°C |
| Machinability (for tube ends) | 20% – Use sharp tools for beveling or threading |
C70600 tube is easy to weld and form compared to many other high-strength copper alloys. This reduces fabrication costs for heat exchangers and piping systems.
What are the Typical Applications for UNS C70600 Tube?
C70600 tube (ASTM B111 / ASTM B466) is used in:
| Application Area | Specific Components |
|---|---|
| Heat exchangers | Condenser tubes, cooler tubes, evaporator tubes |
| Desalination plants | Seawater feed tubes, brine heater tubes |
| Offshore platforms | Seawater cooling lines, firewater mains |
| Shipbuilding | Ballast lines, cooling water systems, sanitary lines |
| Power plants | Cooling water intake tubes, auxiliary cooling |
| Aquaculture | Fish farm seawater supply tubes |
| Hydraulic systems | Seawater hydraulic lines |
Use C70600 tube as an alternative to stainless steel tube in environments where chloride stress corrosion cracking is problematic. C70600 is also preferred over titanium for cost reasons where water velocities are moderate.
FAQ
Q1: What is the difference between ASTM B111 C70600 tube and ASTM B466 C70600 pipe?
A: ASTM B111 C70600 tube is specifically for heat exchangers and condensers – it has tighter dimensional tolerances and is tested by eddy current or hydrostatic methods. ASTM B466 C70600 pipe is for general seawater piping – it has larger diameters and thicker walls. Both are the same C70600 alloy.
Q2: What temper of ASTM B111 C70600 tube is best for bending into U-bends?
A: Annealed (O61) C70600 tube is best for U-bends. It offers 42-50% elongation, allowing tight radius bending without cracking. After bending, the tube may be stress-relieved if required.
Q3: Can UNS C70600 tube be welded to titanium tube in a heat exchanger?
A: Yes, but direct welding of C70600 tube to titanium is not recommended due to brittle intermetallic formation. Use a transition joint (e.g., explosion-bonded C70600/titanium plate) or mechanical fittings.
Q4: What is the maximum seawater velocity for ASTM B111 C70600 tube?
A: C70600 tube can handle seawater velocities up to 3.5 – 4.0 m/s (11-13 ft/s) without erosion corrosion. Above this, consider C71500 (70/30 Cu-Ni) tube.
Q5: Does UNS C70600 tube require post-weld heat treatment?
A: No, C70600 tube typically does not require post-weld heat treatment. However, stress relief annealing at 593-650°C may be used for U-bend tubes or heavily welded sections.
Q6: How does the biofouling resistance of C70600 tube compare to 90/10 Cu-Ni plate?
A: C70600 tube has the same biofouling resistance as plate – excellent. The smooth internal surface of drawn tube actually resists fouling better than rougher surfaces.
Q7: What filler metal should be used for TIG welding ASTM B111 C70600 tube?
A: For TIG welding C70600 tube, use AWS A5.7 ERCuNi filler metal. It matches the 90/10 composition and provides good corrosion resistance.
Q8: Can UNS C70600 tube be used for potable water systems?
A: Yes, C70600 tube is approved for potable water systems. Its corrosion resistance is excellent, and nickel/copper leaching is within WHO and EPA limits.
Q9: What is the difference between C70600 tube and C71500 tube for condenser service?
A: C70600 tube (90/10 Cu-Ni) is more cost-effective and suitable for clean seawater with velocities up to 3.5 m/s. C71500 tube (70/30 Cu-Ni) is stronger, more erosion-resistant, and handles velocities up to 5 m/s – but costs significantly more.
Q10: How is ASTM B111 C70600 tube tested for leaks?
A: C70600 tube is tested by eddy current (ASTM E243) or hydrostatic pressure (ASTM B111). Eddy current is non-destructive and detects internal/external defects. Hydrostatic testing is required for certain applications.
Q11: What is the thermal conductivity of UNS C70600 tube compared to admiralty brass?
A: C70600 tube has thermal conductivity of 40-50 W/mK. Admiralty brass (C44300) is about 100 W/mK. So C70600 conducts less heat, but its superior corrosion resistance often outweighs this for seawater coolers.
Q12: What diameter range is available for ASTM B466 C70600 seamless pipe?
A: GNEE supplies C70600 pipe from 1/4" NB (6mm) up to 12" NB (300mm). Wall thickness ranges from Sch 5 to Sch 80 (and custom).
Q13: Is UNS C70600 tube suitable for sour service (H₂S)?
A: C70600 tube is susceptible to pitting in contaminated water containing hydrogen sulphide – this should be avoided. For sour seawater service, consider C71500 or super duplex stainless steel.
Q14: What is the expansion allowance for ASTM B111 C70600 tube in tube sheets?
A: For C70600 tube rolled into carbon steel tube sheets, allow 8-12% wall reduction. For stainless steel tube sheets, allow 5-8%. Always perform expansion trials first.
Q15: How is ASTM B111 C70600 tube inspected at GNEE?
A: Each C70600 tube undergoes chemical analysis, tensile testing, flattening test, expansion test (for annealed tube), eddy current or hydrostatic test, dimensional inspection, and visual inspection. Mill test reports (MTR) are traceable to heat number.
Quality Inspection for UNS C70600 Tube (ASTM B111 / ASTM B466)
GNEE's inspection process for C70600 tube is tailored specifically to tubular products:
| Test | Method / Standard |
|---|---|
| Chemical composition | Optical emission spectrometer – per ASTM E1476 |
| Tensile strength | ASTM E8 / ASTM B111 – longitudinal strip or full tube |
| Yield strength (0.2% offset) | ASTM E8 – with extensometer |
| Elongation | ASTM E8 – 4D gauge length |
| Flattening test | ASTM B111 – tube flattened to specified gap |
| Expansion test (annealed tube) | ASTM B111 – tube expanded over mandrel |
| Reverse flattening test (welded tube) | ASTM B111 – for welded tube only |
| Eddy current test | ASTM E243 – detects defects non-destructively |
| Hydrostatic test | ASTM B111 / B466 – pressure held for specified time |
| Dimensional inspection | OD (micrometer), ID (pin gauge), wall (ultrasonic) |
| Visual inspection | Internal (borescope), external (naked eye) |
Packaging for ASTM B111 / ASTM B466 UNS C70600 Copper Nickel Tube
| Step | Packaging Action |
|---|---|
| 1 | Blow dry tube interior with compressed air – remove all moisture |
| 2 | Apply plastic end caps (push-fit or threaded) to both ends |
| 3 | Wrap each tube with VCI (vapor corrosion inhibitor) paper |
| 4 | Bundle tubes in hexagonal formation – maximizes stability |
| 5 | Place cardboard or foam layers between tube layers (for polished tubes) |
| 6 | Secure with rust-proof steel strapping (3-5 straps per bundle) |
| 7 | Wrap bundle with PE film (shrink wrap) or woven polypropylene |
| 8 | Place bundle on wooden pallet or inside wooden crate |
| 9 | Attach shipping marks (alloy, temper, OD x WT, length, heat number, weight) |
Factory Equipment
GNEE produces C70600 tube using specialized equipment for tubular products:
| Equipment | Function for Tube Production |
|---|---|
| Induction Furnace (30T) | Melting and alloying C70600 |
| Horizontal Continuous Caster | Casting hollow billets (tube shells) |
| Piercing Mill | Creating hollow shells from solid billet |
| Extrusion Press (2500T) | Forming tube shells to intermediate sizes |
| Cold Drawing Bench (5-150mm) | Precision tube drawing – multiple passes |
| Tube Straightening Machine (6-roll) | Correcting bends and ovality |
| Annealing Furnace (bright anneal) | Protective atmosphere – no scaling |
| Tube Expander / Reducer | Changing diameter at ends |
| Eddy Current Tester | Non-destructive testing (100% inspection) |
| Hydrostatic Tester | Pressure testing for pipe |
| Automatic Tube Cutter | Cutting to customer lengths |
| Spectrometer | In-house chemical analysis |
| Universal Testing Machine | Tensile and yield testing |
Product Range
| Product Category | Typical Specifications / Grades | Available Forms |
|---|---|---|
| Pure Copper | C10100 (OFC), C10200 (OF), C11000 (ETP), C12200 (DHP) | Tube, pipe, bar, plate, sheet, wire, strip, busbar |
| Copper-Nickel Alloys | C70600 (90/10), C71500 (70/30), CuNi30Fe, CuNi10Fe1Mn | Tube, pipe, bar, plate, sheet, fitting, flange, forging |
| Brass Alloys | C26000 (cartridge brass), C27000, C27200, C28000 | Tube, pipe, bar, plate, sheet, strip |
| Free-Cutting Brass | C36000, C37700, C38500 | Bar (round, hex, square) – for machining |
| Naval Brass | C46400, C46500, C48200, C48500 | Bar, plate, sheet |
| Admiralty Brass | C44300, C44400, C44500 | Tube – for heat exchangers |
| Aluminum Brass | C68700 | Tube – for condensers |
| Phosphor Bronze | C51000, C52100, C52400, C54400 | Bar, plate, sheet, strip, wire |
| Aluminum Bronze | C61400, C62300, C63000, C63200, C95400, C95500 | Bar, plate, tube, forging |
| Silicon Bronze | C65100, C65500, C66100 | Bar, tube, wire |
| Beryllium Copper | C17200, C17300, C17500 | Bar, rod, wire, strip |
| Chromium Copper | C18150, C18200, C18400, C18500 | Bar, rod, electrode tip |
| Tin Bronze | C90300, C90500, C90700, C91000 | Cast bar, bearing stock |
| Leaded Bronze | C93200, C93400, C93600, C93700, C93800, C94300 | Cast bar, bearing stock |
| High-Strength Brass / Manganese Bronze | C86300, C86400, C86500, C86600, C86700 | Bar, forging |
| Nickel Silver | C74500, C75200, C75400, C75700, C77000, C79200 | Bar, plate, sheet, strip |
