What is UNS C70600 Copper alloy?
C70600 Copper Nickel Technical Datasheet PDF
UNS C70600 is a copper-nickel alloy containing roughly 90% copper and 10% nickel, with small additions of iron and manganese to stabilise the protective oxide film in seawater service. The same Cu-Ni 90/10 composition is produced in Sheet, plate, coil, Tube, bar, and wire stock - all under one UNS designation and one family of ASTM / ASME / EN / JIS standards.
In seawater, brackish water, and deaerated brine, the alloy forms a thin, adherent, protective oxide layer on the surface that slows turbulent and impingement attack. That corrosion behaviour - not raw strength - is the reason specifiers choose C70600 for condensers, cooler shells, desalination plants, and shipboard heat exchangers.
C70600 Specifications
The table below consolidates the standard specification range for UNS C70600 / Cu-Ni 90/10 in Tube, Sheet, and other mill forms, including the dimension and test grid most engineers reference when adding the alloy to a project specification.
| Item | C70600 Specification |
|---|---|
| UNS designation | UNS C70600 |
| Common name | Copper-Nickel 90/10 (Cu-Ni 90/10) |
| Applicable standards (Tube) | ASTM B111, ASME SB111, EN 12449, DIN 86019, JIS H3300 |
| Applicable standards (Sheet / plate) | ASTM B171, ASME SB171, EN 1652, EN 1653, JIS H3100 |
| Cu content (nominal) | Balance (~88.5–90.5%) |
| Ni content (nominal) | 9.0–11.0% |
| Fe content | 1.0–1.8% |
| Mn content | 1.0% max |
| Zn / Pb / S / C | Zn 1.0% max; Pb, S, C residual limits per ASTM B111 |
| Tensile strength (annealed) | 275–360 MPa (typical) |
| Yield strength (annealed) | 105–150 MPa (typical) |
| Elongation (annealed) | 30% min |
| Hardness range | HRB 35–55 (typical) |
| Tube OD range | 6.0 mm – 60.3 mm (1/4" – 2-3/8") |
| Tube wall thickness range | 0.5 mm – 4.0 mm |
| Tube length range | Up to 12 m (random or cut-to-length) |
| Sheet / plate thickness range | 0.5 mm – 100 mm (plate) |
| Sheet / plate width range | 100 mm – 2,500 mm |
| Dimensional tolerances (Tube OD) | ±0.10 mm standard; tighter on request |
| Dimensional tolerances (Tube wall) | ±10% of nominal wall |
| Length tolerance (cut-to-length) | ±3 mm (≤6 m); ±5 mm (6,100 mm project); ±2 mm on request |
| Standard non-destructive tests | Eddy Current (ASTM E243), Hydrostatic (ASTM B111), Flattening / Expansion |
| Material Test Certificate | EN 10204 Type 3.1 standard; 3.2 with nominated third party |
| Available forms | Seamless straight tube, U-bend tube, coiled tube, finned tube, Sheet, plate, coil, strip, bar, wire |
Related products: in addition to C70600 Seamless straight tube, the same mill supplies companion C70600 fittings (90° / 45° elbows, equal tee, reducing tee, stub-end, cap), matching flanges (ASME B16.5 slip-on and weld-neck), tube-sheet Sheet in cut-to-circle format, and the upstream alloy C68700 (Cu-Ni 80/20 equivalent) for cooler shells and tube sheets where a higher-Ni option is needed.
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Equivalent Grades of UNS C70600
The table below maps UNS C70600 to its equivalents across the standards most often referenced by specifiers in different regions, so that a purchasing team quoting against EN, DIN, BS, GB(T), or JIS standards can match the designation directly without re-doing the chemistry review.
| Standard system | Standard reference | Equivalent grade |
|---|---|---|
| UNS system | UNS C70600 | UNS C70600 (Cu-Ni 90/10) |
| ASTM / ASME (tube) | ASTM B111 / ASME SB111 | C70600 |
| ASTM / ASME (plate, sheet) | ASTM B171 / ASME SB171 | C70600 |
| EN (tube) | EN 12449 / EN 12735 | CuNi10Fe1Mn (CW352H) |
| EN (plate, sheet, strip) | EN 1652 / EN 1653 | CuNi10Fe1Mn (CW352H) |
| EN (rod, bar) | EN 12163 / EN 12167 | CuNi10Fe1Mn (CW352H) |
| DIN | DIN 86019 / DIN 17664 | CuNi10Fe1Mn (2.0872) |
| BS (legacy) | BS 2871 Part 2 (CN 102) | CN 102 |
| GB(T) - China | GB/T 5231, GB/T 4423, GB/T 8889 | BFe10-1-1 (tube); BFe10-1-1 / TFe0.5 (sheet / plate) |
| JIS | JIS H3300 / JIS H3100 | C7060 |
| ISO | ISO 431 | CuNi10Fe1Mn |
Equivalent grade tables matter when the project specifies one standard and the mill is stocking against another. For example, an engineer issuing an RFQ against EN 12449 can match the same chemical composition as a C70600 order booked under ASTM B111, and the MTC can be issued against either reference on request - useful when shipping tubes into a project that cites both EN and ASME.
C70600 vs C68700 vs C71500 - How Engineers Choose Between the Three Copper Alloys
Three copper alloys dominate the marine and exchanger market - C70600 (Cu-Ni 90/10), C71500 (Cu-Ni 70/30), and the aluminium-brass family C68700. The table below highlights the differences specifiers weigh when choosing.
| Attribute | C70600 (Cu-Ni 90/10) | C71500 (Cu-Ni 70/30) | C68700 (Aluminium brass) |
|---|---|---|---|
| Nominal composition | Cu ~89 / Ni 10 / Fe 1 / Mn 1 | Cu ~69 / Ni 30 / Fe 1 / Mn 1 | Cu ~77 / Zn 22 / Al 2 / As 0.04 |
| Seawater corrosion resistance | Very good (standard seawater service) | Best (high-velocity / polluted water) | Good (with iron sacrificial anodes) |
| Typical tensile strength | 275–360 MPa | 345–485 MPa | 310–395 MPa |
| Biofouling resistance | High | High | Moderate |
| Relative cost | Baseline | +50–80% over C70600 | Slightly under C70600 |
| Typical applications | Condenser / cooler tubes, ship piping, desalination | High-salinity brine, offshore firewater, naval | Power-station condensers, refinery overhead |
| Common ASTM standards | ASTM B111 / B171 / B359 | ASTM B111 / B171 / B359 | ASTM B111 / B395 |
Some engineers specify UNS C70600 for general seawater service where biofilm resistance, weldability, and value-for-cost all matter.
For higher salinity, higher velocity, or polluted water where the protective oxide film is under heavier load, many specifiers choose C71500.
Where the tube bundle sits in a fresh-water-cooled power-station condenser, C68700 aluminium brass is often the first choice.
Selection tip: when the project has budget room above the C70600 baseline, request a side-by-side quote for both C70600 and C71500 - same OD × wall × standard, same test plan - so the design team can decide with cost as well as corrosion in view.
C70600 Heat Exchanger Tube Procurement Capabilities
FOB and CFR quotation
Standard quotations are issued FOB China main ports (Shanghai, Tianjin, Qingdao) with CFR and CIF options on request. Each quote covers unit price, total price, packing, lead time, and payment terms on a single one-page PDF so that purchasing teams can route approvals quickly.
MOQ on Seamless straight tube typically starts at one standard production batch (100–500 kg), with tiered pricing breaking at the 1-ton and 5-ton thresholds.
Production lead time
Typical production lead time is 25–35 working days from PO confirmation on standard C70600 Tube sizes under ASTM B111 / ASME SB111. Hollow-billet drawing, bright annealing, and final Eddy Current testing are scheduled in one production campaign so the heat-treatment history stays clean.
Non-standard OD × wall combinations or hard temper outside the catalogue range add 10–15 working days. Rush slots can sometimes be opened for repeat orders - confirm at quotation stage.
Payment terms
Standard terms are T/T 30% deposit + 70% balance against copy of B/L; L/C at sight and D/P at sight are accepted for repeat purchasers. On a first order the deposit locks the production slot, and the balance is released once the MTC and shipping documents are emailed to the purchasing team for verification.
Sample shipments under 50 kg can be settled by Western Union or sample-grade T/T.
Country of origin and export documents
Country of origin is China, supported by a Certificate of Origin (CO) issued by China Customs, FORM A for GSP countries, FORM E for ASEAN destinations, and FORM F under the China-Chile FTA. Standard export documents - commercial invoice, packing list, B/L, MTC, and CO - are bundled with every shipment.
Free-trade-zone and bonded-warehouse releases can be arranged on request; projects on CIF terms should confirm the destination port and the applicable Incoterms edition at quote stage.
Chemical composition and mechanical properties
Each C70600 Tube shipment is delivered with a heat-based chemistry report covering Cu, Ni, Fe, Mn, Zn, Pb, S, and C - measured by OES or wet analysis - together with a mechanical-properties report giving tensile strength, yield strength, elongation, and hardness. Reports reference the standard the lot was tested against (ASTM B111, ASME SB111, EN 12449, or equivalent).
For projects designing against ASME Section II, elevated-temperature tensile data and grain-size charts can be added for shell-side operation above 200 °C.
Dimensional tolerances
Outer-diameter tolerance on ASTM B111 / ASME SB111 C70600 tubes is held inside ±0.10 mm on the OD 19.05 mm (3/4") class, with wall thickness inside ±10% of nominal wall. Length for tubes ≤6 m is cut to ±3 mm; longer tubes fall inside the tighter grid in the standard.
Tighter OD, wall, and ovality tolerances can be quoted on request for tube-sheet pin-registration assemblies.
Material Test Certificate (EN 10204 3.1)
Each delivery carries an EN 10204 Type 3.1 Material Test Certificate signed by the mill quality manager, traceable to the cast heat number. The 3.1 certificate covers chemical composition, mechanical properties, dimensional check, hydrostatic / Eddy Current test results, and the standard of manufacture, all released together with the shipping documents.
Projects that require EN 10204 Type 3.2 (third-party endorsed) can add SGS / BV / TÜV inspection to the same cast.
Compliance with ASTM B111 / ASME SB111
ASTM B111 / ASME SB111 Copper Alloy Tubes for Heat Exchangers Standard PDF
C70600 seamless tubes are produced in compliance with ASTM B111 / ASME SB111, with both standards referenced on the MTC and on each bundle tag. The ASME SB111 mark permits use in ASME Section VIII pressure-vessel applications; the ASTM B111 mark covers the broader chemistry and dimension grid defined in the standard.
A Technical Data Sheet, an MTC sample, and a company profile are attached to the first quote, so the engineering team can attach them to the vendor-approval file without further email exchange.
Third-party inspection by SGS / BV / TÜV
Independent third-party inspection is welcomed from SGS, BV, TÜV, or any other agency the purchaser's quality team nominates. Inspections usually cover four checkpoints: incoming raw material, in-process dimensional and visual check, final Eddy Current / hydrostatic, and pre-shipment container loading.
When EN 10204 3.2 is required, the inspector signs the MTC jointly with the mill quality manager.
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Quality Assurance and Inspection Workflow
Quality assurance on a C70600 order starts at the cast billet and follows the heat number through drawing, annealing, sizing, Eddy Current testing, hydrostatic testing, MTC issuance, and final container loading. The mill is ISO 9001 certified, and heat-level chemical and mechanical test records are retained for at least seven years for re-issue or audit.
Project-critical shipments carry an Inspection and Test Plan (ITP) issued for purchaser approval before production starts. Each ITP hold-point records the standard reference, the acceptance criterion, and the document required for sign-off, so engineering and quality teams can pre-approve the workflow rather than discover gaps at inspection time.
Packing, Marking and Container Loading
Beyond the basic wooden-case packing summarised above, each project shipment is identified with heat-numbered bundle tags, batch-coded end-cap markings, and project-specific consignee references so that receiving inspection can match the bundle to the MTC without opening the case.
Tubes are loaded vertically where the bundle size allows to keep OD roundness within tolerance over long sea voyages, and the container is fitted with desiccant and a kraft paper moisture barrier. Each bundle tag records the standard (ASTM B111 / ASME SB111), the grade (UNS C70600), the size (OD × wall × length), the heat number, the piece count, the net and gross weight, and the consignee / project reference.
FAQ
Q: 1. What is the standard mill length for a C70600 seamless heat-exchanger tube?
A: Standard mill length on a C70600 heat-exchanger tube is up to 6,100 mm (20 ft) random or cut-to-length, with longer lengths up to 12 m available on spool capacity. Custom-cut lengths are held to ±5 mm standard and ±2 mm on request for tube-sheet pin-registration assembly.
Q: 2. Is UNS C70600 the same as Cu-Ni 90/10?
A: Yes - UNS C70600 is the alloy family name for Cu-Ni 90/10. The "90/10" describes the nominal 90% Copper and 10% Nickel split, with iron and manganese additions that stabilise the protective oxide film in seawater service. The same UNS number covers Sheet, plate, bar, wire, and Tube under ASTM B111, B171, B359, and EN 12449 / EN 1652.
Q: 3. Can EN 10204 3.1 be issued on every C70600 Tube order?
A: Yes, EN 10204 Type 3.1 Material Test Certificates are issued on every shipment as standard, traceable to the cast heat number. Projects that require EN 10204 3.2 (third-party endorsed) can add SGS / BV / TÜV inspection against the same cast.
Q: 4. What is the difference between ASTM B111 and ASME SB111 for C70600 Tube?
A: ASTM B111 covers the chemistry, dimensions, and tests for Copper and copper-alloy seamless condenser and heat-exchanger tubes; ASME SB111 is the ASME code version of the same scope. Material produced against either standard can be dual-marked, so the same C70600 Cu-Ni 90/10 Seamless Tubes are acceptable to both bodies for code-stamped vessels and exchangers.
Q: 5. What tolerances and tests apply to a C70600 heat-exchanger tube?
A: Outer-diameter tolerance is ±0.10 mm, wall-thickness tolerance ±10% of nominal, length tolerance ±3 mm (≤6 m) standard / ±5 mm (6,100 mm) project. Every tube is Eddy Current tested to ASTM E243 and may be Hydrostatic tested to ASTM B111 where the heat-exchanger service demands.
Q: 6. Does C70600 require a special welding procedure?
A: C70600 welds cleanly with TIG using a Cu-Ni 10Fe filler, with no pre-heat required on thin-wall heat-exchanger tubes. Post-weld stress-relief is not needed for service below 200 °C; for higher temperatures a low-temperature anneal at ~550 °C recovers the soft-annealed condition.
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