Copper Alloy C70400-WC55
Supply condition
UNS C70400
WC55 = 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.
Values for the WC55 condition
Other C70400 tempers and conditions
C70400 is listed in 6 conditions; see the grade overview at C70400.
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 |
WC55This page 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-WC55?
C70400-WC55 is C70400 supplied in the WC55 condition — welded tube given a light draw for dimensional accuracy and higher yield strength without a final full anneal. C70400-WC55 has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 310 MPa (45 ksi) — stronger than 51% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 138 GPa (20 Msi). C70400-WC55 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). O61 is the default condition FabDigit quotes; WC55 is available on request or by drawing note.
Advantages
- Stiff — 138 GPa (20 Msi), better than 95% of copper alloy grades
- Readily welded — 78/100, better than 91% of copper alloy grades
- Forms and bends easily — 70/100, better than 80% of copper alloy grades
Limitations
- High embodied carbon — 4.6 kg CO₂/kg, worse than 82% of copper alloy grades
C70400-WC55 properties
Typical room-temperature values for C70400-WC55; 20 are specific to this condition. Other listed values are C70400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C70400-WC55 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-WC55 has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 310 MPa (45 ksi) — stronger than 51% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 138 GPa (20 Msi).
Thermal6
C70400-WC55 is rated for continuous service to 250°C (482 °F). It conducts heat at 63 W/m·K (36.4 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-WC55 conducts electricity at 12.5 % IACS, worse than 60% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (71/100), better than 80% of copper alloy grades.
Sustainability4
Producing a kilogram of C70400-WC55 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-WC55's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability very good (78/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C70400-WC55
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.
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.
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 | — |
C70400-WC55 — frequently asked
What is C70400-WC55 used for?
C70400-WC55 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-WC55?
C70400-WC55 has a typical yield strength of 230 MPa (33.4 ksi) and a tensile strength of 310 MPa (45 ksi) — stronger than 51% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C70400-WC55 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% 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-WC55 be welded?
Yes — weldability is rated very good (78/100). 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-WC55?
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-WC55 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-WC55?
C70400-WC55 is rated for continuous use to about 250°C (482 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.