Copper Alloy C68800-H08
Supply condition
UNS C68800
H08 = spring hard
Spring temper for connector contacts and leaf springs needing high elastic limit and low relaxation.
Values for the H08 condition
Other C68800 tempers and conditions
C68800 is listed in 8 conditions; see the grade overview at C68800.
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 | — |
H08This page 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-H08?
C68800-H08 is C68800 supplied in the H08 condition — spring temper for connector contacts and leaf springs needing high elastic limit and low relaxation. C68800-H08 has a yield strength of 745 MPa (108 ksi) and a tensile strength of 814 MPa (118 ksi) — stronger than 97% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 117 GPa (17 Msi). C68800-H08 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). H04 is the default condition FabDigit quotes; H08 is available on request or by drawing note.
Advantages
- High strength — 745 MPa (108 ksi), better than 97% of copper alloy grades
- Low embodied carbon — 3.1 kg CO₂/kg, better than 95% of copper alloy grades
Limitations
- Limited service temperature — 125°C (257 °F), worse than 100% of copper alloy grades
- Limited ductility — 3%, worse than 97% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C68800-H08 properties
Typical room-temperature values for C68800-H08; 10 are specific to this condition. Other listed values are C68800 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C68800-H08 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-H08 has a yield strength of 745 MPa (108 ksi) and a tensile strength of 814 MPa (118 ksi) — stronger than 97% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C68800-H08 is rated for continuous service to 125°C (257 °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-H08 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-H08 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-H08's machinability is fair (35/100, better than 51% of copper alloy grades); weldability poor (25/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68800-H08
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.
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.
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 | — |
C68800-H08 — frequently asked
What is C68800-H08 used for?
C68800-H08 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-H08?
C68800-H08 has a typical yield strength of 745 MPa (108 ksi) and a tensile strength of 814 MPa (118 ksi) — stronger than 97% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C68800-H08 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% 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-H08 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-H08?
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-H08 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-H08?
C68800-H08 is rated for continuous use to about 125°C (257 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.