Copper Alloy C72800-TH04
Precip hard
UNS C72800
TH04 = tD04 and precipitation hardened
Pick for maximum spring force retention in connector contacts and highly loaded flat springs.
Values for the TH04 condition
Other C72800 tempers and conditions
C72800 is listed in 8 conditions; see the grade overview at C72800.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Pick for deep drawing, severe forming or coining before a customer ageing treatment. | 300 | 585 | 32 | 76 HRB | 7 % IACS |
Quarter hard | Pick when moderate forming is still required but higher as-supplied stiffness than soft strip is wanted. | 550 | 690 | 18 | 90 HRB | 7.5 % IACS |
Full hard | Pick for flat blanked parts or as the pre-temper feeding a TH04 ageing cycle. | 790 | 860 | 6 | 22 HRC | 7.5 % IACS |
TF00Default Solution heat treated and precipitation hardened | Default stocked condition: formed soft then aged ~350 °C for high strength with usable ductility and best isotropy. | 800 | 930 | 12 | 30 HRC | 8 % IACS |
Spring hard | Pick for un-aged spring strip needing maximum as-rolled strength with only bend-radius-limited forming. | 880 | 930 | 3 | 26 HRC | 7.5 % IACS |
TD01 and precipitation hardened | Pick when a formed contact needs high aged strength but must still tolerate moderate bends before ageing. | 930 | 1,000 | 9 | 32 HRC | 8.5 % IACS |
TH04This page TD04 and precipitation hardened | Pick for maximum spring force retention in connector contacts and highly loaded flat springs. | 1,080 | 1,140 | 5 | 36 HRC | 8.5 % IACS |
Spring temper cold rolled then spinodally aged | Pick for the highest available strength level in thin strip where forming is limited to gentle bends. | 1,170 | 1,240 | 3 | 39 HRC | 8.5 % IACS |
What is C72800-TH04?
C72800-TH04 is C72800 in the TH04 condition — pick for maximum spring force retention in connector contacts and highly loaded flat springs. C72800-TH04 has a yield strength of 1,080 MPa (157 ksi) and a tensile strength of 1,140 MPa (165 ksi) — stronger than 100% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 138 GPa (20 Msi). C72800-TH04 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,030°C (1,886 °F). TF00 is the default condition FabDigit quotes; TH04 is available on request or by drawing note.
Advantages
- High strength — 1,080 MPa (157 ksi), better than 100% of copper alloy grades
- Stiff — 138 GPa (20 Msi), better than 95% of copper alloy grades
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
- Good corrosion resistance — 74/100, better than 88% of copper alloy grades
Limitations
- Limited ductility — 5%, worse than 93% of copper alloy grades
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades
- High embodied carbon — 5.2 kg CO₂/kg, worse than 88% of copper alloy grades
- Low electrical conductivity — 8.5 % IACS, worse than 79% of copper alloy grades
- Limited formability — 18/100, worse than 75% of copper alloy grades
C72800-TH04 properties
Typical room-temperature values for C72800-TH04; 12 are specific to this condition. Other listed values are C72800 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C72800-TH04 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Mechanical14
C72800-TH04 has a yield strength of 1,080 MPa (157 ksi) and a tensile strength of 1,140 MPa (165 ksi) — stronger than 100% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 138 GPa (20 Msi).
Thermal6
C72800-TH04 is rated for continuous service to 200°C (392 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
C72800-TH04 conducts electricity at 8.5 % IACS, worse than 79% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (74/100), better than 88% of copper alloy grades.
Sustainability4
Producing a kilogram of C72800-TH04 takes about 72 MJ of energy and emits 5.2 kg of CO₂ — more than 86% of copper alloy grades. Typical recycled content is 20%.
Manufacturability8
C72800-TH04's machinability is fair (35/100, better than 51% of copper alloy grades); weldability fair (40/100); formability poor (18/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C72800-TH04
Is C72800 easy to machine?
Gummy and work-hardening in the soft temper — machine in the aged condition with sharp carbide tools, positive rake, moderate speed and generous coolant; chips are stringy (≈20% of AISI 1212).
Can C72800 be welded?
GTAW/EBW feasible with matching or Cu-Ni filler, but the HAZ loses spinodal hardening and Sn segregation can cause hot cracking — re-solution + re-age after welding if strength matters.
Can C72800 be formed, bent or molded?
Do all deep drawing, bending and coining in TB00/H01 temper, then age (typically 340–370 °C, 2–4 h) to final strength; aged strip tolerates only large-radius bends.
What surface finishes work on C72800?
Not anodizable; takes bright polishing well and is readily electroplated with Ni/Sn/Ag/Au underplates for connector contacts.
C72800 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 | 9.5 – 10.5 | 10 |
| Sn | 7.5 – 8.5 | 8 |
| Mndeoxidiser / grain control | 0.05 – 0.3 | 0.15 |
| Nbgrain refiner (per CDA registration) | 0.1 – 0.5 | 0.25 |
| Fe | ≤ 0.5 | — |
| Zn | ≤ 0.5 | — |
| Pb | ≤ 0.02 | — |
| Cu | balance | — |
C72800-TH04 — frequently asked
What is C72800-TH04 used for?
C72800-TH04 is typically used for high-strength connectors, battery contacts and switch springs. In short: high-tin spinodal alloy; holds spring force at 200 °C; beryllium-free high strength.
What is the yield strength of C72800-TH04?
C72800-TH04 has a typical yield strength of 1,080 MPa (157 ksi) and a tensile strength of 1,140 MPa (165 ksi) — stronger than 100% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C72800-TH04 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Gummy and work-hardening in the soft temper — machine in the aged condition with sharp carbide tools, positive rake, moderate speed and generous coolant; chips are stringy (≈20% of AISI 1212).
Can C72800-TH04 be welded?
With care — weldability is rated fair (40/100). GTAW/EBW feasible with matching or Cu-Ni filler, but the HAZ loses spinodal hardening and Sn segregation can cause hot cracking — re-solution + re-age after welding if strength matters.
What surface finishes work on C72800-TH04?
Not anodizable; takes bright polishing well and is readily electroplated with Ni/Sn/Ag/Au underplates for connector contacts.
Can C72800-TH04 be formed, bent or molded?
Do all deep drawing, bending and coining in TB00/H01 temper, then age (typically 340–370 °C, 2–4 h) to final strength; aged strip tolerates only large-radius bends.
What is the maximum service temperature of C72800-TH04?
C72800-TH04 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 C72800-TF00 and C72800-TB00?
TF00 is the default condition — default stocked condition: formed soft then aged ~350 °C for high strength with usable ductility and best isotropy. TB00: pick for deep drawing, severe forming or coining before a customer ageing treatment. Yield strength is 800 MPa in TF00 versus 300 MPa in TB00.
Sources
- ASTM B740 — Copper-Nickel-Tin Spinodal Alloy Strip — ASTM International (2020)
- CDA Alloy Database — C72800 Cu-Ni-Sn — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Spinodal Cu-Ni-Sn strip and bar data (ToughMet/Marunaka-type products) — alloy producers (2022)
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.