Copper Alloy C71900-TF00
Precip hard · default condition
UNS C71900
TF00 = solution heat treated and precipitation hardened
Standard supply condition: best balance of high strength, ductility and stress-relaxation resistance for springs and connectors.
Values for the TF00 condition
Other C71900 tempers and conditions
C71900 is listed in 8 conditions; see the grade overview at C71900.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Pick for deep forming/stamping of complex parts that will be precipitation hardened after shaping. | 200 | 480 | 40 | 130 HB | 4 % IACS |
Solution heat treated and cold worked, quarter hard | Light cold work for parts needing moderate stiffness with residual bend formability before aging. | 400 | 560 | 20 | 160 HB | 4 % IACS |
Solution heat treated and cold worked, half hard | Mid-strength cold-rolled strip/rod for parts that will be aged to final spring properties. | 500 | 620 | 12 | 190 HB | 4 % IACS |
TF00DefaultThis page Solution heat treated and precipitation hardened | Standard supply condition: best balance of high strength, ductility and stress-relaxation resistance for springs and connectors. | 550 | 760 | 15 | 24 HRC | 5.5 % IACS |
Solution heat treated and cold worked, full hard | Fully cold-worked strip/wire where maximum as-rolled strength is needed prior to precipitation hardening. | 620 | 700 | 6 | 20 HRC | 4 % IACS |
TD01 and precipitation hardened | Use where aged strength must rise above TF00 but some bend formability is still required. | 720 | 830 | 10 | 27 HRC | 5.8 % IACS |
TD02 and precipitation hardened | Common spring-strip condition for connector contacts needing high contact force with modest bending. | 830 | 900 | 6 | 30 HRC | 6 % IACS |
TD04 and precipitation hardened | Maximum-strength condition for flat springs and preloaded contacts formed to generous bend radii only. | 930 | 970 | 3 | 33 HRC | 6 % IACS |
What is C71900-TF00?
C71900-TF00 is C71900 in the TF00 condition — standard supply condition: best balance of high strength, ductility and stress-relaxation resistance for springs and connectors. C71900-TF00 has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 92% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 152 GPa (22 Msi). C71900-TF00 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,200°C (2,192 °F).
Advantages
- Stiff — 152 GPa (22 Msi), better than 99% of copper alloy grades
- Good corrosion resistance — 78/100, better than 94% of copper alloy grades
- High service temperature — 320°C (608 °F), better than 93% of copper alloy grades
- High strength — 550 MPa (79.8 ksi), better than 92% of copper alloy grades
Limitations
- Low electrical conductivity — 5.5 % IACS, worse than 95% of copper alloy grades
- Poor heat conductor — 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 90% of copper alloy grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 89% of copper alloy grades
C71900-TF00 properties
Typical room-temperature values for C71900-TF00; 15 are specific to this condition. Other listed values are C71900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C71900-TF00 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,200°C (2,192 °F).
Mechanical14
C71900-TF00 has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 92% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 152 GPa (22 Msi).
Thermal6
C71900-TF00 is rated for continuous service to 320°C (608 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 90% of copper alloy grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
C71900-TF00 conducts electricity at 5.5 % IACS, worse than 95% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 94% of copper alloy grades.
Sustainability4
Producing a kilogram of C71900-TF00 takes about 75 MJ of energy and emits 5.5 kg of CO₂ — more than 88% of copper alloy grades. Typical recycled content is 25%.
Manufacturability7
C71900-TF00's machinability is poor (28/100, worse than 78% of copper alloy grades); weldability good (55/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C71900-TF00
Is C71900 easy to machine?
Gummy, work-hardening Cu-Ni: use sharp positive-rake carbide, rigid setups, heavy constant feed and flood coolant; rate ~20% of free-cutting brass and lower again after aging.
Can C71900 be welded?
GTAW/GMAW with Cu-Ni (ERCuNi) or matching filler is possible, but the HAZ loses the aged condition — re-solution treat and re-age for full strength.
Can C71900 be formed, bent or molded?
Form, stamp and coin in the solution-treated TB00 condition, then precipitation harden; aged tempers need generous bend radii (≥2t transverse) to avoid cracking.
What surface finishes work on C71900?
Not anodizable; takes a bright mechanical or electropolish and accepts Ni/Au or Sn electroplating for connector contact surfaces.
C71900 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 | 28 – 33 | 30 |
| Crprecipitation-hardening element | 2.2 – 3 | 2.6 |
| Fe | ≤ 0.5 | 0.2 |
| Mn | 0.2 – 1 | 0.5 |
| Si | ≤ 0.15 | 0.05 |
| Tigrain/precipitate control | ≤ 0.2 | 0.1 |
| Zrgrain refiner | ≤ 0.2 | 0.12 |
| Zn | ≤ 0.05 | — |
| Pb | ≤ 0.02 | — |
| C | ≤ 0.1 | 0.04 |
| Curemainder, approx. 65–68% | balance | — |
C71900-TF00 — frequently asked
What is C71900-TF00 used for?
C71900-TF00 is typically used for springs, electrical connectors, relay contacts and high-temperature fasteners. In short: strongest wrought cupronickel; age-hardening spring alloy; holds load to 320 °C.
What is the yield strength of C71900-TF00?
C71900-TF00 has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 92% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C71900-TF00 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 78% of copper alloy grades). Gummy, work-hardening Cu-Ni: use sharp positive-rake carbide, rigid setups, heavy constant feed and flood coolant; rate ~20% of free-cutting brass and lower again after aging.
Can C71900-TF00 be welded?
Yes — weldability is rated good (55/100). GTAW/GMAW with Cu-Ni (ERCuNi) or matching filler is possible, but the HAZ loses the aged condition — re-solution treat and re-age for full strength.
What surface finishes work on C71900-TF00?
Not anodizable; takes a bright mechanical or electropolish and accepts Ni/Au or Sn electroplating for connector contact surfaces.
Can C71900-TF00 be formed, bent or molded?
Form, stamp and coin in the solution-treated TB00 condition, then precipitation harden; aged tempers need generous bend radii (≥2t transverse) to avoid cracking.
What is the maximum service temperature of C71900-TF00?
C71900-TF00 is rated for continuous use to about 320°C (608 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C71900-TF00 and C71900-TH04?
TF00 is the default condition — standard supply condition: best balance of high strength, ductility and stress-relaxation resistance for springs and connectors. TH04: maximum-strength condition for flat springs and preloaded contacts formed to generous bend radii only. Yield strength is 550 MPa in TF00 versus 930 MPa in TH04.
Sources
- Copper Alloy C71900 alloy data (UNS listing) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Specialty Handbook: Copper and Copper Alloys — ASM International (2001)
- ASTM B846 — Standard Terminology for Copper and Copper Alloys (temper designations) — ASTM (2020)
- Copper-nickel alloys for seawater service — technical guidance — Nickel Institute / CDA UK (2020)
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.