Copper Alloy C70500-H55
Temper
UNS C70500 · ASTM B111
H55 = light-drawn tube
Pick when straight tube with better handling stiffness and dimensional stability is needed but some expandability must remain.
Values for the H55 condition
Other C70500 tempers and conditions
C70500 is listed in 7 conditions; see the grade overview at C70500.
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 |
H55This page 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 |
What is C70500-H55?
C70500-H55 is C70500 in the H55 temper — pick when straight tube with better handling stiffness and dimensional stability is needed but some expandability must remain. C70500-H55 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 54% of copper alloy grades. Elongation at break is 25% and the elastic modulus is 124 GPa (18 Msi). C70500-H55 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). O61 is the default condition FabDigit quotes; H55 is available on request or by drawing note.
Advantages
- Readily welded — 78/100, better than 91% of copper alloy grades
- Forms and bends easily — 70/100, better than 80% of copper alloy grades
C70500-H55 properties
Typical room-temperature values for C70500-H55; 20 are specific to this condition. Other listed values are C70500 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C70500-H55 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-H55 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 54% of copper alloy grades. Elongation at break is 25% and the elastic modulus is 124 GPa (18 Msi).
Thermal6
C70500-H55 is rated for continuous service to 250°C (482 °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-H55 conducts electricity at 24 % IACS, better than 57% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (57/100), worse than 80% of copper alloy grades.
Sustainability4
Producing a kilogram of C70500-H55 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-H55'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 C70500-H55
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.
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.
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 | — |
C70500-H55 — frequently asked
What is C70500-H55 used for?
C70500-H55 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-H55?
C70500-H55 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 54% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C70500-H55 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% 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-H55 be welded?
Yes — weldability is rated very good (78/100). 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-H55?
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-H55 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-H55?
C70500-H55 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 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.