Copper Alloy C70620
UNS C70620
A tightly composition-controlled 90/10 copper-nickel variant of C70600, often specified for nuclear-grade condenser and heat-exchanger tubing where stricter Fe/Mn limits improve corrosion consistency.
Reference datasheet — C70620 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 O60 condition
C70620 tempers and conditions
C70620 is supplied in 7 conditions, soft to hard. O60 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 |
|---|---|---|---|---|---|---|
O60Default Soft annealed | Standard condition for condenser/heat-exchanger tube, U-bends and cold-formed parts; maximum ductility and best corrosion consistency. | 120 | 310 | 40 | 65 HB | 9.5 % IACS |
As hot rolled | Mill hot-worked plate, tube shell or extrusion, taken as-processed; used where subsequent forming, welding or machining will follow. | 135 | 320 | 35 | 70 HB | 9.5 % IACS |
Quarter hard | Light temper for tube and strip needing higher yield strength while retaining useful bendability. | 255 | 365 | 20 | 95 HB | 9.5 % IACS |
Cold worked and stress relieved | Cold-drawn tube given a low-temperature stress relief to cut residual stress before seawater or condensate service. | 330 | 400 | 15 | 110 HB | 9 % IACS |
Half hard | General structural temper for strip, sheet and drawn tube where strength matters more than deep forming. | 360 | 415 | 12 | 120 HB | 9.5 % IACS |
Extra hard | Heavily cold-worked strip/tube for high-strength, wear- and pressure-resisting parts with only slight forming. | 450 | 490 | 6 | 150 HB | 9.5 % IACS |
Spring hard | Maximum cold-worked strength for springy strip, clips and diaphragms in marine/condensate environments. | 485 | 525 | 4 | 165 HB | 9.5 % IACS |
Supply forms, finishes and certifications
Ways C70620 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, annealed after welding | Surface finish |
What is C70620?
A tightly composition-controlled 90/10 copper-nickel variant of C70600, often specified for nuclear-grade condenser and heat-exchanger tubing where stricter Fe/Mn limits improve corrosion consistency. C70620 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,100°C (2,012 °F). C70620 has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 79% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 124 GPa (18 Msi).
What is C70620 used for?
- nuclear plant condenser tubes
- power plant heat exchangers
- marine piping
Advantages
- Readily welded — 90/100, better than 98% of copper alloy grades
- Good corrosion resistance — 80/100, better than 96% of copper alloy grades
- High service temperature — 315°C (599 °F), better than 92% of copper alloy grades
- Forms and bends easily — 90/100, better than 89% of copper alloy grades
- Ductile — tolerates forming and impact — 40%, better than 84% of copper alloy grades
Limitations
- High embodied carbon — 5.2 kg CO₂/kg, worse than 88% of copper alloy grades
- Poor heat conductor — 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 82% of copper alloy grades
- Low strength — 120 MPa (17.4 ksi), worse than 79% of copper alloy grades
- Low electrical conductivity — 9.5 % IACS, worse than 76% of copper alloy grades
C70620 properties
Typical room-temperature values for C70620-O60; bars are the position among copper alloy grades.
Physical3
C70620 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,100°C (2,012 °F).
Mechanical14
C70620 has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 79% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 124 GPa (18 Msi).
Thermal6
C70620 is rated for continuous service to 315°C (599 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 82% of copper alloy grades. Thermal expansion is 17.1 µm/m·K (9.5 µin/in·°F).
Electrical3
C70620 conducts electricity at 9.5 % IACS, worse than 76% 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 C70620 takes about 70 MJ of energy and emits 5.2 kg of CO₂ — more than 84% of copper alloy grades. Typical recycled content is 25%.
Manufacturability8
C70620's machinability is poor (28/100, worse than 78% of copper alloy grades); weldability excellent (90/100); 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. C70620 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C70620
Is C70620 easy to machine?
Gummy and work-hardening — rate ≈20 % of free-cutting brass; use sharp positive-rake carbide, moderate speed, heavy feed and generous coolant to avoid built-up edge.
Can C70620 be welded?
Designed for welding: GTAW/GMAW with C7158 (65/35 Cu-Ni) filler, no preheat, low interpass temperature, argon back-purge; keep joints oil- and sulphur-free to avoid hot cracking.
Can C70620 be formed, bent or molded?
Excellent cold formability in O60 (deep drawing, U-bending, expansion); work-hardens fast, so interstage anneal at 700–850 °C with rapid cooling; hot work 850–950 °C.
C70620 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 |
|---|---|---|
| Niincludes Co | 9 – 11 | 10 |
| Feiron addition gives impingement resistance | 1 – 1.8 | 1.5 |
| Mncontrolled range (deoxidation, weldability) | 0.5 – 1 | 0.7 |
| Zn | ≤ 0.5 | |
| Pbtightened vs C70600 for weldability | ≤ 0.02 | |
| C | ≤ 0.05 | |
| S | ≤ 0.02 | |
| P | ≤ 0.02 | |
| CuCu + Ag remainder, ≈86.5 % min | balance |
What surface finishes work on C70620?
Not anodizable; pickle in sulphuric/hydrogen-peroxide or inhibited nitric to remove weld oxide, then form the protective film with clean-water commissioning (or FeSO₄ dosing); takes a good mechanical or electro-polish.
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 C70620 cost?
C70620 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.
C70620 — frequently asked
What is C70620 used for?
C70620 is typically used for nuclear plant condenser tubes, power plant heat exchangers and marine piping. In short: nuclear-grade 90/10 cupronickel; tighter Fe/Mn than C70600; excellent seawater weldability.
What is the yield strength of C70620?
C70620 has a typical yield strength of 120 MPa (17.4 ksi) and a tensile strength of 310 MPa (45 ksi) — weaker than 79% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C70620 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 78% of copper alloy grades). Gummy and work-hardening — rate ≈20 % of free-cutting brass; use sharp positive-rake carbide, moderate speed, heavy feed and generous coolant to avoid built-up edge.
Can C70620 be welded?
Yes — weldability is rated excellent (90/100). Designed for welding: GTAW/GMAW with C7158 (65/35 Cu-Ni) filler, no preheat, low interpass temperature, argon back-purge; keep joints oil- and sulphur-free to avoid hot cracking.
What surface finishes work on C70620?
Not anodizable; pickle in sulphuric/hydrogen-peroxide or inhibited nitric to remove weld oxide, then form the protective film with clean-water commissioning (or FeSO₄ dosing); takes a good mechanical or electro-polish.
Can C70620 be formed, bent or molded?
Excellent cold formability in O60 (deep drawing, U-bending, expansion); work-hardens fast, so interstage anneal at 700–850 °C with rapid cooling; hot work 850–950 °C.
What is the maximum service temperature of C70620?
C70620 is rated for continuous use to about 315°C (599 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C70620-O60 and C70620-H08?
O60 is the default condition — standard condition for condenser/heat-exchanger tube, U-bends and cold-formed parts; maximum ductility and best corrosion consistency. H08: maximum cold-worked strength for springy strip, clips and diaphragms in marine/condensate environments. Yield strength is 120 MPa in O60 versus 485 MPa in H08.
How much does C70620 cost?
C70620 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 B466/B466M – Seamless Copper-Nickel Pipe and Tube — ASTM International (2020)
- ASTM B111/B111M – Copper and Copper-Alloy Seamless Condenser Tubes — ASTM International (2021)
- ASTM B171 / B402 – Cu-Ni plate and sheet for condensers — ASTM International (2018)
- CDA alloy datasheet C70600 / C70620 (UNS registration) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties of Copper and Copper Alloys — ASM International (1990)
- Copper-Nickel Alloys for Seawater Systems (technical guide) — Copper Development Association / Nickel Institute (2019)
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.