Copper Alloy C70500
UNS C70500 · ASTM B111
A low-nickel (~2%) copper-nickel alloy offering modest corrosion resistance improvement over pure copper at lower cost than 90/10 or 70/30 cupronickels; used for condenser and heat-exchanger tubing where cost matters.
Reference datasheet — C70500 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
C70500 tempers and conditions
C70500 is supplied in 7 conditions, soft to hard. O61 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O61Default Annealed | Standard condition for condenser and heat-exchanger tube that must be expanded/rolled into tubesheets or U-bent. | 105 | 275 | 40 | 55 HB | 25 % IACS |
Drawn and stress-relieved tube | Use where residual stress from drawing must be reduced (ammonia-bearing atmospheres, U-bend legs) while keeping drawn strength. | 190 | 305 | 28 | 72 HB | 24.5 % IACS |
Light-drawn tube | Pick when straight tube with better handling stiffness and dimensional stability is needed but some expandability must remain. | 200 | 310 | 25 | 75 HB | 24 % IACS |
Quarter hard | Flat-product temper for deep-drawn or formed parts needing more spring than fully soft strip. | 220 | 315 | 22 | 78 HB | 25 % IACS |
Half hard | General-purpose flat temper balancing formability with useful yield strength for brackets, sleeves and shells. | 280 | 350 | 14 | 92 HB | 24 % IACS |
Hard drawn | Highest-strength tube condition for pressure or structural tubing where no significant expansion or bending follows. | 350 | 400 | 8 | 105 HB | 24 % IACS |
Full hard | Choose for flat springs, clips and wear surfaces where only mild bending is required after forming. | 370 | 415 | 6 | 110 HB | 24 % IACS |
Supply forms, finishes and certifications
Ways C70500 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
WO50 | Welded tube, welded and annealed | Surface finish |
What is C70500?
A low-nickel (~2%) copper-nickel alloy offering modest corrosion resistance improvement over pure copper at lower cost than 90/10 or 70/30 cupronickels; used for condenser and heat-exchanger tubing where cost matters. C70500 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,090°C (1,994 °F). C70500 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 40% and the elastic modulus is 124 GPa (18 Msi).
What is C70500 used for?
- condenser tubing
- heat exchanger tubes
- low-cost marine piping
Advantages
- Readily welded — 80/100, better than 93% of copper alloy grades
- Forms and bends easily — 90/100, better than 89% of copper alloy grades
- High service temperature — 300°C (572 °F), better than 85% of copper alloy grades
- Ductile — tolerates forming and impact — 40%, better than 84% 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
C70500 properties
Typical room-temperature values for C70500-O61; bars are the position among copper alloy grades.
Physical3
C70500 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,090°C (1,994 °F).
Mechanical12
C70500 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 40% and the elastic modulus is 124 GPa (18 Msi).
Thermal6
C70500 is rated for continuous service to 300°C (572 °F). It conducts heat at 90 W/m·K (52 BTU/hr·ft·°F), better than 54% of copper alloy grades. Thermal expansion is 17.1 µm/m·K (9.5 µin/in·°F).
Electrical3
C70500 conducts electricity at 25 % IACS, better than 59% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C70500 takes about 60 MJ of energy and emits 4 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 35%.
Manufacturability6
C70500's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability very good (80/100); formability excellent (90/100).
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. C70500 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C70500
Is C70500 easy to machine?
Gummy and work-hardening like all cupronickels — use sharp positive-rake carbide, ~60–100 m/min, heavy feed and generous coolant to avoid built-up edge; rating only about 20 % of free-cutting brass.
Can C70500 be welded?
Readily GTAW/GMAW welded with ERCuNi (70/30) filler under argon, no preheat and no post-weld heat treatment; keep joints clean and sulphur/lead-free to avoid hot cracking, and avoid oxyacetylene.
Can C70500 be formed, bent or molded?
Excellent cold formability in O61 — bends, expands and U-bends well; interanneal near 700–800 °C for heavy reductions and stress-relieve drawn tube if ammonia exposure is expected.
C70500 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 |
|---|---|---|
| Ninickel (may be reported as Ni+Co); nominal 2 % low-nickel cupronickel | 1.5 – 2.5 | 2 |
| Feiron addition for impingement resistance; verify exact limits against current CDA/ASTM registration | 0.1 – 1 | 0.5 |
| Mndeoxidiser / sulphur scavenger | 0 – 1 | 0.4 |
| Znimpurity limit | ≤ 0.5 | |
| Pbimpurity limit | ≤ 0.05 | |
| Cimpurity limit | ≤ 0.05 | |
| Simpurity limit | ≤ 0.02 | |
| Curemainder, approximately 96–98 % | balance |
What surface finishes work on C70500?
Solders and brazes easily with proper flux; not anodizable — finish by pickling/passivation, mechanical polishing or tin/nickel plating, and expect a protective brown-green patina in seawater service.
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).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C70500 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B111
How much does C70500 cost?
C70500 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.
C70500 — frequently asked
What is C70500 used for?
C70500 is typically used for condenser tubing, heat exchanger tubes and low-cost marine piping. In short: cheapest cupronickel tube grade; softer than 90/10 Cu-Ni; high formability, low machinability.
What is the yield strength of C70500?
C70500 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 7 listed tempers.
Is C70500 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Gummy and work-hardening like all cupronickels — use sharp positive-rake carbide, ~60–100 m/min, heavy feed and generous coolant to avoid built-up edge; rating only about 20 % of free-cutting brass.
Can C70500 be welded?
Yes — weldability is rated very good (80/100). Readily GTAW/GMAW welded with ERCuNi (70/30) filler under argon, no preheat and no post-weld heat treatment; keep joints clean and sulphur/lead-free to avoid hot cracking, and avoid oxyacetylene.
What surface finishes work on C70500?
Solders and brazes easily with proper flux; not anodizable — finish by pickling/passivation, mechanical polishing or tin/nickel plating, and expect a protective brown-green patina in seawater service.
Can C70500 be formed, bent or molded?
Excellent cold formability in O61 — bends, expands and U-bends well; interanneal near 700–800 °C for heavy reductions and stress-relieve drawn tube if ammonia exposure is expected.
What is the maximum service temperature of C70500?
C70500 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 C70500-O61 and C70500-H04?
O61 is the default condition — standard condition for condenser and heat-exchanger tube that must be expanded/rolled into tubesheets or U-bent. H04: choose for flat springs, clips and wear surfaces where only mild bending is required after forming. Yield strength is 105 MPa in O61 versus 370 MPa in H04.
How much does C70500 cost?
C70500 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)
- CDA/UNS Copper Alloy Property Data (C705xx copper-nickels) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Copper-Nickel Alloys: Properties and Application Guidance — Nickel Institute / CDA UK (2016)
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.