Copper Alloy C64800
UNS C64800
C64800 is a cobalt-bearing silicon bronze that responds to precipitation hardening, part of the wrought silicon bronze family and normally supplied as fine wire, strip and flat spring stock in solution-treated, cold-worked and aged tempers.
Reference datasheet — C64800 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 TF00 condition
C64800 tempers and conditions
C64800 is supplied in 9 conditions, soft to hard. TF00 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 |
|---|---|---|---|---|---|---|
Soft annealed | Softest condition for maximum drawability or deep forming before hardening. | 140 | 380 | 40 | 80 HB | 30 % IACS |
Solution heat treated | Supersaturated, ductile starting condition for forming or wire drawing before aging. | 165 | 410 | 35 | 88 HB | 22 % IACS |
Solution heat treated and cold worked, half hard | Intermediate strength/ductility balance for parts that will still be bent or formed. | 420 | 500 | 12 | 135 HB | 21 % IACS |
Solution heat treated and cold worked, full hard | Work-hardened wire/strip when no subsequent aging step is available. | 500 | 570 | 8 | 168 HB | 20 % IACS |
TF00Default Solution heat treated and precipitation hardened | Standard stocked condition: best combination of strength, conductivity and stability after aging. | 590 | 690 | 10 | 93 HRB | 45 % IACS |
Cold worked spring temper | Heavily drawn fine wire for springs where a bake/age cycle is not applied. | 600 | 660 | 3 | 12 HRC | 19 % IACS |
TD02 and precipitation hardened | Mill-hardened half-hard strip/wire when moderate formability must survive with high strength. | 650 | 720 | 8 | 17 HRC | 44 % IACS |
TD04 and precipitation hardened | High-strength mill-hardened condition for contact springs and clips. | 720 | 790 | 5 | 21 HRC | 43 % IACS |
Spring temper cold worked then precipitation hardened | Maximum-strength fine wire/strip for highly stressed springs and connectors. | 810 | 860 | 2 | 26 HRC | 42 % IACS |
What is C64800?
C64800 is a cobalt-bearing silicon bronze that responds to precipitation hardening, part of the wrought silicon bronze family and normally supplied as fine wire, strip and flat spring stock in solution-treated, cold-worked and aged tempers. It is selected for springs and current-carrying contacts that need 590 MPa yield and 690 MPa tensile at 93 HRB while holding 45% IACS conductivity and 175 W/m·K. Elongation is only 10%, maximum service temperature is about 200 °C, and aged strength is lost in any weld heat-affected zone. C64700 gives more ductility at lower strength. C64800 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 1,030°C (1,886 °F). C64800 has a yield strength of 590 MPa (85.6 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 94% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 130 GPa (18.9 Msi).
What is C64800 used for?
- springs
- electrical contacts
- fine wire
Advantages
- High strength — 590 MPa (85.6 ksi), better than 94% of copper alloy grades
- Stiff — 130 GPa (18.9 Msi), better than 89% of copper alloy grades
- High electrical conductivity — 45 % IACS, better than 77% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- Limited ductility — 10%, worse than 76% of copper alloy grades
C64800 properties
Typical room-temperature values for C64800-TF00; bars are the position among copper alloy grades.
Physical3
C64800 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Mechanical11
C64800 has a yield strength of 590 MPa (85.6 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 94% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 130 GPa (18.9 Msi).
Thermal6
C64800 is rated for continuous service to 200°C (392 °F). It conducts heat at 175 W/m·K (101.1 BTU/hr·ft·°F), better than 74% of copper alloy grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
C64800 conducts electricity at 45 % IACS, better than 77% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C64800 takes about 58 MJ of energy and emits 3.8 kg of CO₂ — more than 61% of copper alloy grades. Typical recycled content is 30%.
Manufacturability7
C64800's machinability is fair (35/100, better than 51% of copper alloy grades); weldability good (60/100); 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. C64800 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C64800
Is C64800 easy to machine?
Machines like other silicon bronzes — gummy, ~30 % of AISI 1212; use sharp positive-rake tools, high speed, generous coolant, and machine in the aged condition for better chip control.
Can C64800 be welded?
GTAW/resistance and laser welding are feasible with silicon-bronze filler, but the aged strength is lost in the HAZ, so re-age or design joints away from spring sections; remove silica film before welding.
Can C64800 be formed, bent or molded?
Do heavy drawing, coiling and bending in the solution-treated or partly cold-worked state, then age at ~450–500 °C for strength recovery and springback stabilization.
C64800 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 |
|---|---|---|
| Siprimary precipitate former with Co (Co–Si intermetallics); nominal, verify against CDA/UNS registration | 1.4 – 2.2 | 1.8 |
| Cocobalt addition gives the precipitation-hardening response | 0.3 – 1.2 | 0.7 |
| Feimpurity/partial Co substitute | ≤ 0.3 | |
| Znimpurity limit | ≤ 0.5 | |
| Pbimpurity limit | ≤ 0.05 | |
| Curemainder, ~96–98 % | balance |
What surface finishes work on C64800?
No anodizing; tin, nickel or gold plating for contacts (nickel underplate recommended), and it polishes well or can be chemically patinated for decorative use.
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 C64800 cost?
C64800 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.
C64800 — frequently asked
What is C64800 used for?
C64800 is typically used for springs, electrical contacts and fine wire. In short: highest-strength silicon bronze; spring alloy with 45% IACS; age-hardenable contact material.
What is the yield strength of C64800?
C64800 has a typical yield strength of 590 MPa (85.6 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 94% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C64800 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Machines like other silicon bronzes — gummy, ~30 % of AISI 1212; use sharp positive-rake tools, high speed, generous coolant, and machine in the aged condition for better chip control.
Can C64800 be welded?
Yes — weldability is rated good (60/100). GTAW/resistance and laser welding are feasible with silicon-bronze filler, but the aged strength is lost in the HAZ, so re-age or design joints away from spring sections; remove silica film before welding.
What surface finishes work on C64800?
No anodizing; tin, nickel or gold plating for contacts (nickel underplate recommended), and it polishes well or can be chemically patinated for decorative use.
Can C64800 be formed, bent or molded?
Do heavy drawing, coiling and bending in the solution-treated or partly cold-worked state, then age at ~450–500 °C for strength recovery and springback stabilization.
What is the maximum service temperature of C64800?
C64800 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 C64800-TF00 and C64800-O60?
TF00 is the default condition — standard stocked condition: best combination of strength, conductivity and stability after aging. O60: softest condition for maximum drawability or deep forming before hardening. Yield strength is 590 MPa in TF00 versus 140 MPa in O60.
How much does C64800 cost?
C64800 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
- UNS/CDA copper alloy designation registration (C6xxxx silicon bronzes) — Copper Development Association (2023)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM (2019)
- copper.org alloy property database (silicon and nickel-silicon bronzes) — CDA (2024)
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.