Copper Alloy C72900-TM08
Precip hard
UNS C72900
TM08 = mill hardened, spring hard
Maximum-strength mill-hardened strip for highly loaded springs where forming is limited to shallow bends.
Values for the TM08 condition
Other C72900 tempers and conditions
C72900 is listed in 7 conditions; see the grade overview at C72900.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Soft solution-annealed stock for deep forming/machining of complex parts before customer spinodal ageing. | 280 | 520 | 35 | 78 HRB | 4.5 % IACS |
Mill hardened, half hard | Choose when stamped/formed springs and contacts must still bend appreciably after mill hardening. | 655 | 760 | 9 | 25 HRC | 7 % IACS |
Mill hardened, full hard | Balanced mill-hardened temper for connector springs needing higher stress relaxation resistance with moderate bending. | 760 | 860 | 7 | 29 HRC | 7.2 % IACS |
Mill hardened, extra hard | High-strength mill-hardened strip for flat springs and clips with mostly straight or gentle-radius forming. | 895 | 965 | 5 | 33 HRC | 7.5 % IACS |
TF00Default Solution heat treated and precipitation hardened | Standard high-strength bearing/bushing condition — pick for machined bushings, wear plates and downhole hardware. | 1,000 | 1,105 | 10 | 35 HRC | 7.5 % IACS |
TM08This page Mill hardened, spring hard | Maximum-strength mill-hardened strip for highly loaded springs where forming is limited to shallow bends. | 1,000 | 1,070 | 4 | 36 HRC | 7.5 % IACS |
cold worked after ageing, extra-high strength rod | Cold-worked-and-aged rod for the highest yield strength, e.g. fasteners, valve stems and heavily loaded pins. | 1,105 | 1,200 | 6 | 39 HRC | 7 % IACS |
What is C72900-TM08?
C72900-TM08 is C72900 in the TM08 condition — maximum-strength mill-hardened strip for highly loaded springs where forming is limited to shallow bends. C72900-TM08 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,070 MPa (155 ksi) — stronger than 99% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 131 GPa (19 Msi). C72900-TM08 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,050°C (1,922 °F). TF00 is the default condition FabDigit quotes; TM08 is available on request or by drawing note.
Advantages
- High strength — 1,000 MPa (145 ksi), better than 99% of copper alloy grades
- Good corrosion resistance — 78/100, better than 94% of copper alloy grades
- Stiff — 131 GPa (19 Msi), better than 91% of copper alloy grades
- Easy to machine — 65/100, better than 76% of copper alloy grades
Limitations
- Limited ductility — 4%, worse than 96% of copper alloy grades
- High embodied carbon — 7 kg CO₂/kg, worse than 96% of copper alloy grades
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades
- Low electrical conductivity — 7.5 % IACS, worse than 84% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C72900-TM08 properties
Typical room-temperature values for C72900-TM08; 11 are specific to this condition. Other listed values are C72900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C72900-TM08 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,050°C (1,922 °F).
Mechanical14
C72900-TM08 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,070 MPa (155 ksi) — stronger than 99% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 131 GPa (19 Msi).
Thermal5
C72900-TM08 is rated for continuous service to 240°C (464 °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 16.7 µm/m·K (9.28 µin/in·°F).
Electrical3
C72900-TM08 conducts electricity at 7.5 % IACS, worse than 84% 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 C72900-TM08 takes about 95 MJ of energy and emits 7 kg of CO₂ — more than 95% of copper alloy grades. Typical recycled content is 25%.
Manufacturability7
C72900-TM08's machinability is good (65/100, better than 76% of copper alloy grades); weldability poor (25/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C72900-TM08
Is C72900 easy to machine?
Machines well in the aged condition with short chips — use sharp carbide, 60–120 m/min, positive rake, rigid setups and flood coolant; avoid dwelling to prevent work hardening.
Can C72900 be welded?
Fusion welding is not recommended (tin segregation and loss of spinodal temper); use mechanical joints, EB/laser only with qualified procedures, or silver brazing accepting local softening.
Can C72900 be formed, bent or molded?
Form in the solution-annealed (TB00) condition or use low mill-hardened tempers (TM02/TM04); aged material is limited to shallow bends with generous radii, then age 350–400 °C to develop strength.
What surface finishes work on C72900?
Takes a fine polish; no anodising — protect or enhance with passivation, tin/silver/nickel plating, or DLC/PVD for extreme wear; nitric-based pickles remove aged oxide.
C72900 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 | 14.5 – 15.5 | 15 |
| Sn | 7.5 – 8.5 | 8 |
| Mndeoxidiser/grain control | ≤ 0.3 | 0.15 |
| Feimpurity limit | ≤ 0.5 | — |
| Znimpurity limit | ≤ 0.5 | — |
| Pbimpurity limit | ≤ 0.02 | — |
| Curemainder, ~76–78 % | balance | — |
C72900-TM08 — frequently asked
What is C72900-TM08 used for?
C72900-TM08 is typically used for bearings & bushings, gears, high-load springs and downhole oilfield components. In short: strongest Cu-Ni-Sn alloy; beryllium-free bearing alloy; galling-resistant under high load.
What is the yield strength of C72900-TM08?
C72900-TM08 has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,070 MPa (155 ksi) — stronger than 99% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C72900-TM08 easy to machine?
Reasonably — machinability is rated good (65/100, better than 76% of copper alloy grades). Machines well in the aged condition with short chips — use sharp carbide, 60–120 m/min, positive rake, rigid setups and flood coolant; avoid dwelling to prevent work hardening.
Can C72900-TM08 be welded?
Not readily — weldability is rated poor (25/100). Fusion welding is not recommended (tin segregation and loss of spinodal temper); use mechanical joints, EB/laser only with qualified procedures, or silver brazing accepting local softening.
What surface finishes work on C72900-TM08?
Takes a fine polish; no anodising — protect or enhance with passivation, tin/silver/nickel plating, or DLC/PVD for extreme wear; nitric-based pickles remove aged oxide.
Can C72900-TM08 be formed, bent or molded?
Form in the solution-annealed (TB00) condition or use low mill-hardened tempers (TM02/TM04); aged material is limited to shallow bends with generous radii, then age 350–400 °C to develop strength.
What is the maximum service temperature of C72900-TM08?
C72900-TM08 is rated for continuous use to about 240°C (464 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C72900-TF00 and C72900-TB00?
TF00 is the default condition — standard high-strength bearing/bushing condition — pick for machined bushings, wear plates and downhole hardware. TB00: soft solution-annealed stock for deep forming/machining of complex parts before customer spinodal ageing. Yield strength is 1,000 MPa in TF00 versus 280 MPa in TB00.
Sources
- ToughMet 3 AT / TS Alloy Data (C72900) — Materion Brush Performance Alloys (2023)
- ASTM B929 — Copper-Nickel-Tin Spinodal Alloy Rod, Bar and Shapes — ASTM International (2020)
- ASTM B740 — Copper-Nickel-Tin Spinodal Alloy Strip — ASTM International (2020)
- CDA Alloy Database — C72900 properties — Copper Development Association (2024)
- 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.