Copper Alloy C68800
UNS C68800
C68800 is a high-strength aluminum brass used mainly as strip for springs and contacts, reaching 725 MPa tensile, 620 MPa yield, 90 HRB and 5 % elongation in the default temper.
Reference datasheet — C68800 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 H04 condition
C68800 tempers and conditions
C68800 is supplied in 8 conditions, soft to hard. H04 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.035 mm grain size | Softest commercial strip condition for deep drawing and severe forming. | 275 | 545 | 40 | 70 HRB | — |
Annealed to 0.015 mm grain size | Fine-grain annealed strip: best combination of formability and a smooth drawn surface. | 310 | 565 | 36 | 75 HRB | — |
Quarter hard | Light cold work when moderate strength must be kept together with bending across the grain. | 450 | 620 | 20 | 155 HB | 18 % IACS |
Half hard | Balanced temper for formed contacts and clips that still need 90° bends. | 517 | 655 | 12 | 168 HB | 18 % IACS |
H04Default Full hard | Most commonly stocked strip temper: high strength with usable bending along the grain. | 620 | 725 | 5 | 90 HRB | — |
Extra hard | Higher strength for flat stampings with only gentle forming along the rolling direction. | 690 | 772 | 4 | 92 HRB | — |
Spring hard | Spring temper for connector contacts and leaf springs needing high elastic limit and low relaxation. | 745 | 814 | 3 | 94 HRB | — |
Extra spring hard | Maximum-strength temper for flat springs and contact fingers formed only along the grain. | 772 | 841 | 3 | 95 HRB | — |
What is C68800?
C68800 is a high-strength aluminum brass used mainly as strip for springs and contacts, reaching 725 MPa tensile, 620 MPa yield, 90 HRB and 5 % elongation in the default temper. Engineers select it where spring force must be combined with brass-level corrosion resistance in stamped parts; it is stocked in OS035 and OS015 annealed and H01–H10 rolled tempers. Elongation and formability are low in hard tempers (formability rating 45), service is limited to about 150 °C, and the Al₂O₃ film prevents arc welding and requires activation before plating. C68800 has a density of 8.17 g/cm³ (0.295 lb/in³), lighter than 86% of copper alloy grades. It melts at 932°C (1,710 °F). C68800 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 95% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 117 GPa (17 Msi).
What is C68800 used for?
- springs
- electrical connectors
- corrosion-resistant fasteners
Advantages
- High strength — 620 MPa (89.9 ksi), better than 95% of copper alloy grades
- Low embodied carbon — 3.1 kg CO₂/kg, better than 95% of copper alloy grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
- Limited ductility — 5%, worse than 93% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C68800 properties
Typical room-temperature values for C68800-H04; bars are the position among copper alloy grades.
Physical3
C68800 has a density of 8.17 g/cm³ (0.295 lb/in³), lighter than 86% of copper alloy grades. It melts at 932°C (1,710 °F).
Mechanical11
C68800 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 95% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C68800 is rated for continuous service to 150°C (302 °F). It conducts heat at 71 W/m·K (41 BTU/hr·ft·°F), worse than 54% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C68800 conducts electricity at 18 % IACS, better than 51% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C68800 takes about 46 MJ of energy and emits 3.1 kg of CO₂ — less than 94% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
C68800's machinability is poor (33/100, worse than 53% of copper alloy grades); weldability poor (25/100); 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. C68800 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C68800
Is C68800 easy to machine?
Chips are tough and gummy — rate ~30% of free-cutting brass; use sharp positive-rake carbide, high speed, flood coolant, and avoid dwelling in hard tempers.
Can C68800 be welded?
Arc (TIG/MIG) welding is not recommended because of the aluminium oxide film; use resistance spot/seam welding, silver brazing with aggressive flux, or soft soldering after film removal.
Can C68800 be formed, bent or molded?
Stamp and form in OS015/H02 for tight radii; in H04–H10 restrict bends to along the rolling direction and allow high springback due to the ~620–770 MPa yield.
C68800 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 |
|---|---|---|
| Cu | 71 – 77 | 73.5 |
| Alforms protective alumina-rich film | 3 – 3.8 | 3.4 |
| Cograin refiner / strengthener | 0.25 – 0.55 | 0.4 |
| Asdezincification inhibitor | 0.02 – 0.08 | 0.04 |
| Fe | ≤ 0.05 | |
| Pb | ≤ 0.05 | |
| Zn | balance |
What surface finishes work on C68800?
Not anodizable; degrease and acid-activate (fluoride-bearing pickle) to strip the Al₂O₃ film before nickel/tin/gold plating, otherwise leave as bright-rolled or mechanically polished.
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 C68800 cost?
C68800 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.
C68800 — frequently asked
What is C68800 used for?
C68800 is typically used for springs, electrical connectors and corrosion-resistant fasteners. In short: highest-strength brass strip; spring-temper aluminum brass; not arc weldable.
What is the yield strength of C68800?
C68800 has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 95% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C68800 easy to machine?
Not especially — machinability is rated poor (33/100, worse than 53% of copper alloy grades). Chips are tough and gummy — rate ~30% of free-cutting brass; use sharp positive-rake carbide, high speed, flood coolant, and avoid dwelling in hard tempers.
Can C68800 be welded?
Not readily — weldability is rated poor (25/100). Arc (TIG/MIG) welding is not recommended because of the aluminium oxide film; use resistance spot/seam welding, silver brazing with aggressive flux, or soft soldering after film removal.
What surface finishes work on C68800?
Not anodizable; degrease and acid-activate (fluoride-bearing pickle) to strip the Al₂O₃ film before nickel/tin/gold plating, otherwise leave as bright-rolled or mechanically polished.
Can C68800 be formed, bent or molded?
Stamp and form in OS015/H02 for tight radii; in H04–H10 restrict bends to along the rolling direction and allow high springback due to the ~620–770 MPa yield.
What is the maximum service temperature of C68800?
C68800 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C68800-H04 and C68800-OS035?
H04 is the default condition — most commonly stocked strip temper: high strength with usable bending along the grain. OS035: softest commercial strip condition for deep drawing and severe forming. Yield strength is 620 MPa in H04 versus 275 MPa in OS035.
How much does C68800 cost?
C68800 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 B592 — Copper-Zinc-Aluminum-Cobalt Alloy (UNS C68800) Plate, Sheet, Strip and Rolled Bar — ASTM International (2021)
- CDA Alloy Datasheet C68800 — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Alloy 688 high-performance strip data — Olin Brass / Global Brass and Copper (2018)
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.