Copper Alloy C72700
UNS C72700
C72700 is a spinodal-hardenable Cu-Ni-Sn alloy with moderate tin content, sitting between C72500 and C72800 in the wrought copper-nickel family.
Reference datasheet — C72700 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 TH01 condition
C72700 tempers and conditions
C72700 is supplied in 9 conditions, soft to hard. TH01 is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Softest, most formable condition; choose when deep forming or heavy coining precedes a customer spinodal age. | 240 | 480 | 35 | 72 HRB | 9 % IACS |
Solution heat treated and cold worked, quarter hard | Light cold work for formed parts that will be spinodal aged (to TH01) after stamping. | 450 | 560 | 15 | 166 HB | 9 % IACS |
Solution heat treated and cold worked, half hard | Balanced strength/bendability strip for stamped springs that receive a post-form age. | 550 | 620 | 9 | 91 HRB | 9 % IACS |
Solution heat treated and cold worked, full hard | Hard cold-rolled strip for flat springs and contacts where only simple bends are needed before aging. | 680 | 720 | 4 | 96 HRB | 9 % IACS |
TH01Default TD01 and precipitation hardened | Most commonly stocked mill-hardened strip: high spring strength with usable bend formability and no post-form heat treatment. | 730 | 800 | 8 | 23 HRC | 11 % IACS |
Mill hardened, full hard | Producer-controlled mill-hardened temper balancing formability and yield strength for connector stamping lines. | 790 | 840 | 8 | 25 HRC | 11 % IACS |
TD02 and precipitation hardened | Higher-strength mill-hardened temper for compact contacts with moderate bend requirements. | 810 | 870 | 6 | 26 HRC | 11 % IACS |
TD04 and precipitation hardened | Maximum-strength aged strip for highly loaded flat springs where only gentle bends are formed. | 900 | 950 | 4 | 29 HRC | 11 % IACS |
Mill hardened, spring hard | Top mill-hardened strength level for miniature high-force contacts; formability is limited to gentle bends. | 950 | 1,000 | 4 | 30 HRC | 11 % IACS |
What is C72700?
C72700 is a spinodal-hardenable Cu-Ni-Sn alloy with moderate tin content, sitting between C72500 and C72800 in the wrought copper-nickel family. It is used for demanding connectors and springs because the default condition reaches 730 MPa yield, 800 MPa tensile, 8% elongation and 23 HRC while keeping 11% IACS conductivity and 33 W/m·K. Strip and wire are supplied solution-treated (TB00), cold-rolled (TD) or mill-hardened (TH/TM) so parts can be formed soft and aged afterwards. Maximum service temperature is 200 °C, machinability is 30 and formability is 45, so tight bends must be made before aging; C72900 is the choice when higher strength is required. C72700 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,060°C (1,940 °F). C72700 has a yield strength of 730 MPa (106 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 97% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 131 GPa (19 Msi).
What is C72700 used for?
- high-reliability connectors
- springs
- electronic contacts
Advantages
- High strength — 730 MPa (106 ksi), better than 97% of copper alloy grades
- Stiff — 131 GPa (19 Msi), better than 91% of copper alloy grades
- Good corrosion resistance — 72/100, better than 84% of copper alloy grades
Limitations
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades
- High embodied carbon — 4.8 kg CO₂/kg, worse than 84% of copper alloy grades
- Limited ductility — 8%, worse than 83% of copper alloy grades
C72700 properties
Typical room-temperature values for C72700-TH01; bars are the position among copper alloy grades.
Physical3
C72700 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,060°C (1,940 °F).
Mechanical12
C72700 has a yield strength of 730 MPa (106 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 97% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 131 GPa (19 Msi).
Thermal6
C72700 is rated for continuous service to 200°C (392 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
C72700 conducts electricity at 11 % IACS, worse than 68% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 84% of copper alloy grades.
Sustainability4
Producing a kilogram of C72700 takes about 68 MJ of energy and emits 4.8 kg of CO₂ — more than 83% of copper alloy grades. Typical recycled content is 25%.
Manufacturability7
C72700's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability fair (35/100); formability fair (45/100).
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. C72700 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C72700
Is C72700 easy to machine?
Machines like a tough Cu-Ni: ~20 % of free-cutting brass, use sharp carbide, positive rake, generous coolant and heavier feeds to avoid work hardening; aged tempers cut with better chip control than annealed.
Can C72700 be welded?
Resistance and laser welding are practical; fusion welding softens the aged spinodal structure in the HAZ, so join before aging or accept local strength loss — solders and silver brazes wet the alloy well.
Can C72700 be formed, bent or molded?
Form in TB00/TD01 for deep or tight bends then spinodal age (typically ~350–400 °C, several hours) for peak strength; mill-hardened TH/TM tempers allow only moderate bends, mostly good-way.
C72700 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 |
|---|---|---|
| Ni | 8.5 – 9.5 | 9 |
| Sn | 5.5 – 6.5 | 6 |
| Mndeoxidizer/grain control | 0.05 – 0.3 | 0.15 |
| Mg | ≤ 0.15 | |
| Nbmax, grain refiner | ≤ 0.1 | |
| Fe | ≤ 0.5 | |
| Zn | ≤ 0.5 | |
| Pb | ≤ 0.02 | |
| Curemainder, nominally ~84 % | balance |
What surface finishes work on C72700?
Not anodizable — plate with Ni underlayer plus Sn, Ag or Au for contacts; takes a bright polish and forms a stable dull-bronze oxide in 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).
How much does C72700 cost?
C72700 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.
C72700 — frequently asked
What is C72700 used for?
C72700 is typically used for high-reliability connectors, springs and electronic contacts. In short: spinodal-hardened Cu-Ni-Sn; stronger than C72500; beryllium-free contact alloy.
What is the yield strength of C72700?
C72700 has a typical yield strength of 730 MPa (106 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 97% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C72700 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Machines like a tough Cu-Ni: ~20 % of free-cutting brass, use sharp carbide, positive rake, generous coolant and heavier feeds to avoid work hardening; aged tempers cut with better chip control than annealed.
Can C72700 be welded?
With care — weldability is rated fair (35/100). Resistance and laser welding are practical; fusion welding softens the aged spinodal structure in the HAZ, so join before aging or accept local strength loss — solders and silver brazes wet the alloy well.
What surface finishes work on C72700?
Not anodizable — plate with Ni underlayer plus Sn, Ag or Au for contacts; takes a bright polish and forms a stable dull-bronze oxide in service.
Can C72700 be formed, bent or molded?
Form in TB00/TD01 for deep or tight bends then spinodal age (typically ~350–400 °C, several hours) for peak strength; mill-hardened TH/TM tempers allow only moderate bends, mostly good-way.
What is the maximum service temperature of C72700?
C72700 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C72700-TH01 and C72700-TB00?
TH01 is the default condition — most commonly stocked mill-hardened strip: high spring strength with usable bend formability and no post-form heat treatment. TB00: softest, most formable condition; choose when deep forming or heavy coining precedes a customer spinodal age. Yield strength is 730 MPa in TH01 versus 240 MPa in TB00.
How much does C72700 cost?
C72700 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 B740 — Copper-Nickel-Tin Spinodal Alloy Strip — ASTM International (2020)
- CDA Standard Designations for Wrought Copper Alloys (C72700) — Copper Development Association (2023)
- BrushForm 725 / Cu-9Ni-6Sn strip data — Materion (2022)
- ASM Handbook Vol. 2 — Properties of Copper and Copper Alloys — ASM International (1990)
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.