Copper Alloy C70400
UNS C70400
C70400 is a 95Cu-5Ni wrought copper-nickel with small iron and manganese additions, covered by the C70000-series wrought copper-nickel specifications and stocked in O61, OS025, H55, H80, WO50 and WC55 tempers.
Reference datasheet — C70400 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the O61 condition
C70400 tempers and conditions
C70400 is supplied in 6 conditions, soft to hard. O61 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Welded tube, welded and annealed | Lower-cost welded (ERW) tube fully annealed after welding, for condenser and desalination service per ASTM B543. | 100 | 275 | 42 | 70 HB | 13 % IACS |
O61Default Annealed | Default condition for condenser and heat-exchanger tube that must be bent, expanded or roller-rolled into tubesheets. | 105 | 275 | 46 | 70 HB | 13 % IACS |
Annealed to 0.025 mm grain size | Grain-size-controlled anneal ordered when deep drawing or consistent expansion behaviour of tube/strip is required. | 115 | 285 | 44 | 75 HB | 13 % IACS |
Welded tube, welded and lightly cold worked | Welded tube given a light draw for dimensional accuracy and higher yield strength without a final full anneal. | 230 | 310 | 22 | 90 HB | 12.5 % IACS |
Light drawn (light cold worked) tube | Choose when straighter, stiffer tube with higher yield strength is needed but some expansion/bending is still required. | 240 | 315 | 25 | 92 HB | 12.5 % IACS |
Hard drawn | Highest-strength cold-worked condition for pressure piping and fittings where no further forming is needed. | 345 | 380 | 12 | 120 HB | — |
What is C70400?
C70400 is a 95Cu-5Ni wrought copper-nickel with small iron and manganese additions, covered by the C70000-series wrought copper-nickel specifications and stocked in O61, OS025, H55, H80, WO50 and WC55 tempers. It is chosen for seawater corrosion resistance at the lowest nickel content in the family, with 275 MPa tensile strength, 105 MPa yield, 46 % elongation and 65 W/m·K thermal conductivity; normal forms are condenser tube, pipe and fittings. Strength is modest, machinability rates only 22, and service is capped near 300 °C; move to 90/10 or 70/30 Cu-Ni where seawater velocity or strength demands are higher. C70400 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,099°C (2,010 °F). C70400 has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 85% of copper alloy grades. Elongation at break is 46% and the elastic modulus is 138 GPa (20 Msi).
What is C70400 used for?
- seawater piping
- condenser tubes
- heat exchanger tubes
- marine fittings
Advantages
- Ductile — tolerates forming and impact — 46%, better than 96% of copper alloy grades
- Stiff — 138 GPa (20 Msi), better than 95% of copper alloy grades
- Readily welded — 80/100, better than 93% of copper alloy grades
- Forms and bends easily — 92/100, better than 91% of copper alloy grades
- Good corrosion resistance — 75/100, better than 90% of copper alloy grades
Limitations
- Difficult to machine — 22/100, worse than 94% of copper alloy grades
- Low strength — 105 MPa (15.2 ksi), worse than 85% of copper alloy grades
- High embodied carbon — 4.6 kg CO₂/kg, worse than 82% of copper alloy grades
C70400 properties
Typical room-temperature values for C70400-O61; bars are the position among copper alloy grades.
Physical3
C70400 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,099°C (2,010 °F).
Mechanical12
C70400 has a yield strength of 105 MPa (15.2 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 85% of copper alloy grades. Elongation at break is 46% and the elastic modulus is 138 GPa (20 Msi).
Thermal6
C70400 is rated for continuous service to 300°C (572 °F). It conducts heat at 65 W/m·K (37.6 BTU/hr·ft·°F), worse than 57% of copper alloy grades. Thermal expansion is 16.3 µm/m·K (9.06 µin/in·°F).
Electrical3
C70400 conducts electricity at 13 % IACS, worse than 58% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), better than 90% of copper alloy grades.
Sustainability4
Producing a kilogram of C70400 takes about 65 MJ of energy and emits 4.6 kg of CO₂ — more than 81% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C70400's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability very good (80/100); formability excellent (92/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C70400 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C70400
Is C70400 easy to machine?
Gummy and work-hardening like most Cu-Ni: use sharp positive-rake carbide, moderate speed, heavy feed and flood coolant; chip breaking is poor (≈20 % of AISI 1212).
Can C70400 be welded?
Excellent by GTAW/GMAW with Cu-Ni 70/30 (ERCuNi) filler; keep interpass temperature low, use argon backing on tube, and never weld with lead- or sulphur-contaminated surfaces.
Can C70400 be formed, bent or molded?
Very good cold formability in O61/OS temper — bending, expanding, U-bending and deep drawing all practical; interanneal at 700–850 °C and hot work at 850–950 °C.
C70400 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| NiNi + Co | 4.8 – 6.2 | 5.5 |
| Fekey for erosion-corrosion resistance | 1.3 – 1.7 | 1.5 |
| Mn | 0.3 – 0.8 | 0.5 |
| Zn | ≤ 1 | |
| Pb | ≤ 0.05 | |
| C | ≤ 0.05 | |
| S | ≤ 0.02 | |
| Curemainder, Cu + Ag; ≈92 % | balance |
What surface finishes work on C70400?
Not anodisable; usually left bare to form its protective seawater film, or tin/nickel plated and soldered/brazed easily; degrease thoroughly before service to promote uniform passive film.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
How much does C70400 cost?
C70400 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C70400 — frequently asked
What is C70400 used for?
C70400 is typically used for seawater piping, condenser tubes, heat exchanger tubes and marine fittings. In short: lowest-nickel marine Cu-Ni; highest formability in family; tube and fitting grade.
What is the yield strength of C70400?
C70400 has a typical yield strength of 105 MPa (15.2 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 85% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C70400 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Gummy and work-hardening like most Cu-Ni: use sharp positive-rake carbide, moderate speed, heavy feed and flood coolant; chip breaking is poor (≈20 % of AISI 1212).
Can C70400 be welded?
Yes — weldability is rated very good (80/100). Excellent by GTAW/GMAW with Cu-Ni 70/30 (ERCuNi) filler; keep interpass temperature low, use argon backing on tube, and never weld with lead- or sulphur-contaminated surfaces.
What surface finishes work on C70400?
Not anodisable; usually left bare to form its protective seawater film, or tin/nickel plated and soldered/brazed easily; degrease thoroughly before service to promote uniform passive film.
Can C70400 be formed, bent or molded?
Very good cold formability in O61/OS temper — bending, expanding, U-bending and deep drawing all practical; interanneal at 700–850 °C and hot work at 850–950 °C.
What is the maximum service temperature of C70400?
C70400 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C70400-O61 and C70400-H80?
O61 is the default condition — default condition for condenser and heat-exchanger tube that must be bent, expanded or roller-rolled into tubesheets. H80: highest-strength cold-worked condition for pressure piping and fittings where no further forming is needed. Yield strength is 105 MPa in O61 versus 345 MPa in H80.
How much does C70400 cost?
C70400 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B111/B111M — Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock — ASTM International (2021)
- ASTM B543 — Welded Copper and Copper-Alloy Heat Exchanger Tube — ASTM International (2020)
- ASTM B466/B466M — Seamless Copper-Nickel Pipe and Tube — ASTM International (2020)
- CDA alloy datasheet UNS C70400 — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (copper-nickel in seawater) — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.