C70600 Copper-Nickel Tube Price Update

UNS C70600 is a 90/10 copper-nickel alloy with small but deliberate additions of iron and manganese. It is specified for the most aggressive seawater applications: power-plant condensers, desalination evaporators, marine piping, offshore firewater systems, and shipbuilding.

The alloy's surface forms a stable oxide film in seawater that resists both uniform corrosion and impingement attack. Unlike C68700 aluminum brass, C70600 also shows strong resistance to biofouling: marine organisms attach far less readily to the copper-nickel surface, reducing cleaning cycles and maintaining heat-transfer efficiency over decades.

That performance comes at a price. At current metal levels, C70600 condenser tubes land roughly 18% above C68700 and 45% below C71500 (Cu-Ni 70/30). For many owners, the higher upfront cost is recovered through lower maintenance and avoided retubing.

The two-metal cost pressure is the headline. Because C70600 is ~89% copper and ~10% nickel, a 1% move in either metal moves the raw-material envelope by roughly $130–160 per tonne. In the current range, that makes C70600 roughly $3,000 per tonne more expensive than C68700 on a delivered basis.

The chart below breaks the indicative landed price of an ASTM B111 / ASTM B466 C70600 seamless tube into five components. FOB China basis, week of 25 September 2026.

C70600 price decomposition (left) and three-alloy landed-price comparison (right), September 2026. Source: LME official prices 25 Sep 2026; fabrication premiums reflect ASTM B111 quality level.

The fabrication premium for C70600 is structurally higher than for C11000 or C68700 because the alloy is harder to draw, requires tighter atmosphere control during anneal, and must pass the same condenser-tube tests plus nickel-specific chemistry checks.

The right-hand panel of the chart compares three common seawater tube alloys. The relationship is simple: higher nickel content means higher first cost and longer service life.

For most commercial desalination and power-plant projects, C70600 is the sweet spot: it gives most of C71500's durability at roughly 80% of the price, while outperforming C68700 in biofouling resistance and velocity tolerance.

Higher first cost is not always a cost increase. Three engineering factors make C70600 the lower total-cost option over a project life cycle:

Biofouling resistance. Marine growth on C68700 and carbon-steel tubes reduces heat transfer and forces periodic mechanical cleaning. C70600's copper-nickel surface naturally suppresses fouling, cutting maintenance hours and preserving thermal efficiency.

Velocity tolerance. C70600 can handle seawater velocities up to 3.5 m/s without impingement attack. C68700 is typically limited to ~3 m/s, and carbon steel far less. Higher design velocity can mean smaller tube bundles and lower pumping power.

Retubing interval. A C70600 condenser tube bundle often lasts 25–35 years. C68700 may need partial retubing at 12–18 years. The avoided shutdown, labor, scaffolding, and lost generation cost usually exceeds the initial $3,000/t premium.

The break-even calculation depends on electricity value, labor cost, and outage schedule, but for baseload power or large desalination trains the premium is usually recovered well before the first major overhaul.

With the decision now only two days away, any order placed today will still be in production when the policy lands. The most exposed buyers are those shipping C70600 tubes into North America under fixed-price contracts signed before the deadline.

Recommended contract language for Q4 orders:

LME reference date: state exactly which official fixing is used.

Tariff adjustment clause: if a duty is imposed, the increase is passed through or shared 50/50.

Destination flexibility: allow supplier to ship through an alternative port if a tariff targets a specific country of origin.

Force majeure carve-out: define "trade-policy change" as a pricing event, not a cancellation event.

If no tariff is announced, expect some of the recent physical premium to unwind quickly as metal held in anticipation of a duty returns to global circulation.

A C70600 order is high-value and long-life. The MTC is the only document that proves you received the alloy you paid for. Require:

UNS/EN/GB/JIS designation matching the drawing

Chemical composition: Cu, Ni, Fe, Mn within specified ranges

Temper: typically O61 (annealed) for condenser tubes

Tensile test: yield strength, ultimate strength, elongation

Flattening and expansion tests per ASTM B111 / ASTM B466

Eddy-current test (ECT) 100% of tubes

Hydrostatic test at specified pressure

Dimensional inspection: OD, wall, length, ovality within tolerance

Surface finish: clean, bright, free of scale and carbon

Traceability: heat number and test reports linked to the shipment

Lock metal reference by 30 September, even if you do not lock the full order. The tariff decision is binary; if a duty lands, your next quote could be 5–15% higher overnight.

Separate the copper escalator from the nickel escalator. Copper and nickel move on different fundamentals. A contract that fixes fabrication premium but floats both metals separately is fairer to both parties.

Use the LME Ni pullback if it extends. Nickel stocks have risen above 280 kt, and the metal is better supplied than copper. Any short-term nickel weakness is a buying window for C70600.

Confirm Fe and Mn on the MTC. Missing iron or manganese values are a red flag. Those elements are what make the protective film stable in flowing seawater.

Match the alloy to the velocity. If your design seawater velocity is below 2.5 m/s and asset life is under 15 years, C68700 may be the better economic choice. Above 3 m/s or above 25 years, C70600 is usually justified.

We manufacture and export ASTM B111 / ASTM B466 / EN 12451 C70600 seamless copper-nickel tubes and pipes for marine, desalination, and power-plant projects. Standard sizes and typical tolerances are listed below; non-standard sizes, U-bends, and third-party inspection are available on request.

All tubes ship with: MTC (chemical + mechanical), eddy-current test report, hydrostatic test certificate, and third-party inspection witness if required.