Copper Alloy C71520-H55
Temper
UNS C71520
H55 = light drawn
Choose for condenser/heat-exchanger tube needing slightly higher strength and straightness than fully annealed while still expandable into tubesheets.
Values for the H55 condition
Other C71520 tempers and conditions
C71520 is listed in 8 conditions; see the grade overview at C71520.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O60Default Soft annealed | Default stock condition for seawater tube, plate and fittings — maximum formability and best corrosion behaviour. | 140 | 380 | 45 | 85 HB | 4.6 % IACS |
As hot forged and air cooled | Standard mill condition for hot-forged valve bodies, flanges and fittings that are not subsequently annealed. | 165 | 380 | 40 | 95 HB | 4.6 % IACS |
As forged and quenched | Forgings water-quenched from finishing temperature to retain a solutionised, scale-free structure with the best seawater corrosion behaviour. | 170 | 395 | 42 | 90 HB | 4.6 % IACS |
As-welded deposit | Deposited ERCuNi filler condition — use these numbers when sizing joints in 90/10 and 70/30 Cu-Ni piping and vessels. | 250 | 400 | 30 | 105 HB | 4.3 % IACS |
H55This page Light drawn | Choose for condenser/heat-exchanger tube needing slightly higher strength and straightness than fully annealed while still expandable into tubesheets. | 255 | 415 | 30 | 110 HB | 4.6 % IACS |
Quarter hard | Use where moderate strength increase is needed but the part still has to be bent or flared. | 310 | 450 | 25 | 125 HB | — |
Half hard | Intermediate strength strip, rod and tube for fasteners, sleeves and machined fittings. | 415 | 505 | 15 | 150 HB | 4.5 % IACS |
Full hard | Pick for maximum strength and stiffness in springs, shafting and hard-drawn tube where little further forming is required. | 525 | 585 | 8 | 175 HB | — |
What is C71520-H55?
C71520-H55 is C71520 in the H55 temper — choose for condenser/heat-exchanger tube needing slightly higher strength and straightness than fully annealed while still expandable into tubesheets. C71520-H55 has a yield strength of 255 MPa (37 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 55% of copper alloy grades. Elongation at break is 30% and the elastic modulus is 152 GPa (22 Msi). C71520-H55 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,171°C (2,140 °F). O60 is the default condition FabDigit quotes; H55 is available on request or by drawing note.
Advantages
- Stiff — 152 GPa (22 Msi), better than 99% of copper alloy grades
- Good corrosion resistance — 80/100, better than 96% of copper alloy grades
- Readily welded — 86/100, better than 96% of copper alloy grades
- High service temperature — 300°C (572 °F), better than 85% of copper alloy grades
- Forms and bends easily — 70/100, better than 80% of copper alloy grades
Limitations
- Low electrical conductivity — 4.6 % IACS, worse than 96% of copper alloy grades
- High embodied carbon — 6.6 kg CO₂/kg, worse than 96% of copper alloy grades
- Poor heat conductor — 29 W/m·K (16.8 BTU/hr·ft·°F), worse than 93% of copper alloy grades
C71520-H55 properties
Typical room-temperature values for C71520-H55; 20 are specific to this condition. Other listed values are C71520 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C71520-H55 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,171°C (2,140 °F).
Mechanical14
C71520-H55 has a yield strength of 255 MPa (37 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 55% of copper alloy grades. Elongation at break is 30% and the elastic modulus is 152 GPa (22 Msi).
Thermal6
C71520-H55 is rated for continuous service to 300°C (572 °F). It conducts heat at 29 W/m·K (16.8 BTU/hr·ft·°F), worse than 93% of copper alloy grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
C71520-H55 conducts electricity at 4.6 % IACS, worse than 96% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 96% of copper alloy grades.
Sustainability4
Producing a kilogram of C71520-H55 takes about 90 MJ of energy and emits 6.6 kg of CO₂ — more than 93% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
C71520-H55's machinability is poor (28/100, worse than 78% of copper alloy grades); weldability excellent (86/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C71520-H55
Is C71520 easy to machine?
Gummy and work-hardening — run sharp positive-rake carbide at low speed, heavy positive feed and generous coolant; rating only about 20% of AISI 1212.
Can C71520 be welded?
Very good with GTAW/GMAW using ERCuNi (Ti-deoxidised) filler, no preheat, low interpass temperature, and scrupulously clean, oil- and sulphur-free surfaces to avoid porosity and hot cracking.
Can C71520 be formed, bent or molded?
Excellent cold formability in O60 — deep draws, tube bends and expansions are routine; interanneal at 700–850 °C followed by rapid cooling after roughly 50% reduction, and hot work at 850–1000 °C.
What surface finishes work on C71520?
Takes a bright polish and self-forms a protective brown-green patina in seawater; do not anodize — use pickling/passivation, tin or nickel plating, or marine paint over an etch primer where colour matching is needed.
C71520 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 plus cobalt | 29 – 33 | 31 |
| Feessential for erosion-corrosion resistance | 0.4 – 1 | 0.6 |
| Mn | ≤ 1 | 0.6 |
| Zn | ≤ 1 | — |
| Pb0.02 max for condenser tube per ASTM B111 | ≤ 0.05 | — |
| C | ≤ 0.05 | — |
| S | ≤ 0.02 | — |
| P | ≤ 0.02 | — |
| Tionly in ERCuNi filler per AWS A5.7 (deoxidiser) | 0.2 – 0.5 | 0.3 |
| Cu65.0 % min including silver | balance | — |
C71520-H55 — frequently asked
What is C71520-H55 used for?
C71520-H55 is typically used for welding of Cu-Ni piping, marine pipe fabrication and condenser repair welds. In short: 70/30 Cu-Ni filler metal; matches base-metal corrosion; top weldability in family.
What is the yield strength of C71520-H55?
C71520-H55 has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 55% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C71520-H55 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 78% of copper alloy grades). Gummy and work-hardening — run sharp positive-rake carbide at low speed, heavy positive feed and generous coolant; rating only about 20% of AISI 1212.
Can C71520-H55 be welded?
Yes — weldability is rated excellent (86/100). Very good with GTAW/GMAW using ERCuNi (Ti-deoxidised) filler, no preheat, low interpass temperature, and scrupulously clean, oil- and sulphur-free surfaces to avoid porosity and hot cracking.
What surface finishes work on C71520-H55?
Takes a bright polish and self-forms a protective brown-green patina in seawater; do not anodize — use pickling/passivation, tin or nickel plating, or marine paint over an etch primer where colour matching is needed.
Can C71520-H55 be formed, bent or molded?
Excellent cold formability in O60 — deep draws, tube bends and expansions are routine; interanneal at 700–850 °C followed by rapid cooling after roughly 50% reduction, and hot work at 850–1000 °C.
What is the maximum service temperature of C71520-H55?
C71520-H55 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 C71520-O60 and C71520-H04?
O60 is the default condition — default stock condition for seawater tube, plate and fittings — maximum formability and best corrosion behaviour. H04: pick for maximum strength and stiffness in springs, shafting and hard-drawn tube where little further forming is required. Yield strength is 140 MPa in O60 versus 525 MPa in H04.
Sources
- ASTM B111/B111M — Copper and Copper-Alloy Seamless Condenser Tubes — ASTM International (2021)
- ASTM B466/B466M — Seamless Copper-Nickel Pipe and Tube — ASTM International (2020)
- AWS A5.7/A5.7M — Copper and Copper-Alloy Bare Welding Rods and Electrodes (ERCuNi) — American Welding Society (2007)
- C71520 alloy datasheet — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Copper-Nickel Alloys: Properties and Applications in Seawater Systems — Nickel Institute / CDA (2018)
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.