What C68700 Is - And Why It Is Not Interchangeable with C11000
UNS C68700 is an aluminum brass alloy nominally described as CuZn20Al2As: roughly 76–79% copper, 19–22% zinc, 1.8–2.5% aluminum, and 0.02–0.06% arsenic. The arsenic is intentional. It forms a barrier against dezincification, the selective leaching of zinc that destroys ordinary brass in seawater within months.
| Property | Typical value |
|---|---|
| Copper content | 76.0–79.0% |
| Zinc content | 19.0–22.0% |
| Aluminum content | 1.8–2.5% |
| Arsenic content | 0.02–0.06% |
| Tensile strength, annealed | ≥340 MPa (50 ksi) |
| Elongation, annealed | ≥25% |
| Thermal conductivity | ~100 W/m·K |
| Max seawater velocity | Up to 3 m/s |
Because of that chemistry, C68700 is specified wherever chlorides are present: power-station condensers, seawater desalination evaporators, marine heat exchangers, and offshore HVAC systems. It is not a substitute for C11000 electrical busbar or C12200 HVAC tubing; it is a different material solving a different failure mode.
Global Equivalent Designations for C68700
Procurement teams often receive drawings specifying one national designation and must source from mills certified to another. The table below maps the most common C68700 equivalents. The chemistry is essentially the same; the difference is the certification standard each mill tests to.
| Designation system | Grade code | Common standards | Notes |
|---|---|---|---|
| UNS (USA) | C68700 | ASTM B111, ASTM B395, ASME SB-111 | Most common spec for condenser and heat-exchanger tubes |
| EN (Europe) | CW702R / CuZn20Al2As | EN 12451, EN 12449 | Wrought form; EN 12451 covers tubes for heat exchangers |
| GB/T (China) | HAl77-2 / HAL77-2 | GB/T 8890, GB/T 5231 | Condenser and heat-exchanger tubes; 77% Cu nominal |
| JIS (Japan) | C6870 | JIS H3300, JIS H3250 | Equivalent chemistry and temper range |
| DIN (Germany) | 2.0460 / CuZn20Al2 | DIN 1785, DIN 17660 | Often superseded by EN CW702R in new projects |
| BS (UK) | CZ110 / CZ111 | BS 2871, BS EN 12451 | CZ110 is the legacy British designation |
| ISO | CuZn20Al2As | ISO 1634 | General material designation |
Market Snapshot - September 18–20, 2026
| Indicator | Value | What it means for C68700 |
|---|---|---|
| LME 3-month copper (18 Sep close) | $14,515 / tonne | Up ~2.3% on the week; primary cost driver |
| LME cash vs 3-month | +$14.5 / tonne | Mild backwardation; tight prompt supply |
| Yangshan copper premium | $124 / tonne | Near 4-year high; Asian physical demand firm |
| SHFE copper 2610 | 109,900 yuan / tonne | Domestic Chinese contract benchmark |
| Spot #1 cathode (China) | 110,290 yuan / tonne | Spot premium widening |
| Zinc (LME) | ~$2,800 / tonne | Secondary alloy component, ~20% of alloy mass |
| FOMC decision | +25 bp on 16 Sep | First rate hike since 2023; USD support capped copper gains |
| US copper tariff deadline | 30 Sep 2026 | Binary risk for North American landed costs |
The takeaway for C68700 buyers is straightforward: the raw-material envelope is rising, but the bigger pressure point is the physical premium. When refined copper is scarce in the Asian spot market, alloy mills compete with wire-rod and cathode buyers for the same cathode units. That competition pushes C68700 lead times out and raises the fabrication premium.
C68700 Tube Price Build-Up
Unlike C11000 or C12200 products, a C68700 tube invoice contains five moving parts, not one. The chart below shows an indicative landed price for an ASTM B111 C68700 seamless condenser tube, FOB China basis, as of mid-September 2026.
C68700 landed price decomposition, September 2026. Source: LME official prices 18 Sep 2026, industry data for Zn/Al, and indicative fabrication premium for ASTM B111 quality level.
| Component | Indicative USD/t | Share of total | Notes |
|---|---|---|---|
| LME Cu contribution (77% Cu @ $14,515) | $11,249 | ~67% | The single largest input |
| Zinc content (20% @ ~$2,800) | $560 | ~3.3% | Alloy component, not an LME reference |
| Aluminum content (2% @ ~$2,700) | $54 | ~0.3% | Minor but necessary for oxide film |
| Regional & fabrication premium | $3,850 | ~23% | Extrusion, cold drawing, bright anneal, ECT, hydro test |
| Tariff & freight buffer | $1,100 | ~6.5% | Varies by destination; may spike after 30 Sep |
| Indicative landed price | ~$16,813 / tonne | 100% | Typical range $16,000–$18,500 depending on size/Qty |
The fabrication premium is the part most buyers underestimate. C68700 condenser tubes are not commodity plumbing tube. They must pass:
Eddy-current testing (ECT) for through-wall defects
Hydrostatic testing at 1.5× design pressure
Dimensional checks within ±0.02 mm for precision condenser bundles
Bright anneal to restore corrosion resistance after cold drawing
Chemical and mechanical MTCs per ASTM B111
Those steps are why the "alloy premium" can exceed the entire zinc and aluminum metal value combined.
Three Price Drivers Specific to C68700
Copper content still dominates, but not as much as you think
At ~77% copper by mass, C68700 carries most of the copper-price risk. Yet nearly one-third of the final tube cost comes from zinc, aluminum, processing, and logistics. When copper rallies 20% year-to-date but zinc is flat, the percentage cost increase for C68700 is actually smaller than for pure copper products - a useful fact to remember when negotiating escalator clauses.
Fabrication capacity is concentrated
Seamless aluminum-brass condenser tubes require specialized extrusion presses, bright-annealing furnaces, and ECT lines. Not every copper-tube mill can make them. When demand from desalination and power-plant projects rises simultaneously, the fabrication premium expands fast - regardless of what LME copper does that day.
The 30 September tariff deadline is a one-way option
If North American import duties on copper products are confirmed after 30 September, C68700 tubes shipped into the United States could face an immediate landed-cost jump. Because C68700 tubes are often engineered-to-order with 6–10 week lead times, a tariff announced in late September would hit orders already in production. Buyers shipping to North America should discuss tariff-adjustment clauses and alternative routing before placing Q4 orders.
What to Verify on a C68700 Quote
A C68700 purchase order is high-value and long-life. The MTC is your only protection against a sub-standard tube that will fail in seawater. Require the supplier to confirm:
UNS/EN/GB/JIS designation matching your drawing
Chemical composition: Cu, Zn, Al, and As within specified ranges
Temper: typically O61 (annealed) for condenser tubes
Mechanical test: tensile strength, yield strength, elongation
Corrosion test: dezincification resistance per ASTM B111 or equivalent
NDE: eddy-current test 100% of tubes
Pressure test: hydrostatic test at specified pressure
Dimensions: OD, wall thickness, length within project tolerances
Surface finish: bright, clean, no scale or carbon residue
Traceability: heat number and test reports linked to the delivery batch
Procurement Recommendations for Late September 2026
Lock Q4 tube orders before the National Day holiday break. Chinese mills typically stop accepting new orders 1–2 weeks before the October holiday, and post-holiday lead times often stretch into November.
Separate the copper escalator from the fabrication premium. The fabrication portion of C68700 is less volatile than LME copper; locking it now protects your project margin.
Ask for the As content on the MTC. The 0.02–0.06% arsenic range is what prevents dezincification. A certificate without arsenic analysis is not a valid C68700 certificate.
Specify the standard, not just the alloy. ASTM B111, EN 12451, GB/T 8890, and JIS H3300 have different testing requirements. Make sure the quoted tube is certified to the standard your project expects.
Plan for the tariff buffer. If your destination market is North America, add at least a 5–10% contingency to landed costs until the 30 September decision is public.
Consider C70600 (CuNi 90/10) for extreme service. If design life exceeds 25 years or seawater velocity is above 3 m/s, Cu-Ni may be the more cost-effective choice despite the higher upfront metal cost.
C68700 Tube Range We Supply
We manufacture and export ASTM B111 / EN 12451 C68700 seamless aluminum-brass tubes for condenser, heat-exchanger, and desalination projects. Standard offering and typical tolerances are shown below; custom sizes and third-party inspection are available on request.
| Product form | Standard sizes | Temper | Standards |
|---|---|---|---|
| C68700 condenser tubes | OD 6–57 mm, wall 0.4–4.0 mm, length up to 12 m | O61 (annealed) | ASTM B111, ASME SB-111, EN 12451 |
| C68700 heat-exchanger tubes | OD 10–76 mm, wall 0.8–5.0 mm | O61 / H55 | ASTM B111, EN 12451 |
| C68700 finned tubes | OD 12–38 mm with extruded or wrapped fins | O61 | Customer spec / ASTM B359 reference |
| C68700 U-bends | Custom radius, typically 1D–3D | O61 | ASTM B163 / project drawing |
All tubes ship with: MTC (chemical + mechanical), eddy-current test report, hydrostatic test certificate, and third-party inspection witness if required.
Request a C68700 Quote
Send us your tubing specification, destination port, and required delivery window. We will return an itemized quotation separating the LME copper reference, regional premium, and fabrication premium so you can compare offers on an apples-to-apples basis.
