Copper Alloy C68800-OS035
Temper
UNS C68800
OS035 = annealed to 0.035 mm grain size
Softest commercial strip condition for deep drawing and severe forming.
Values for the OS035 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 |
|---|---|---|---|---|---|---|
OS035This page 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-OS035?
C68800-OS035 is C68800 in the OS035 temper — softest commercial strip condition for deep drawing and severe forming. C68800-OS035 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 545 MPa (79 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 117 GPa (17 Msi). C68800-OS035 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; OS035 is available on request or by drawing note.
Advantages
- Low embodied carbon — 3.1 kg CO₂/kg, better than 95% of copper alloy grades
- Ductile — tolerates forming and impact — 40%, better than 84% of copper alloy grades
- Forms and bends easily — 80/100, better than 83% of copper alloy grades
Limitations
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C68800-OS035 properties
Typical room-temperature values for C68800-OS035; 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-OS035 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-OS035 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 545 MPa (79 ksi) — stronger than 57% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C68800-OS035 is rated for continuous service to 200°C (392 °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-OS035 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-OS035 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-OS035's machinability is poor (28/100, worse than 78% of copper alloy grades); weldability poor (25/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68800-OS035
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-OS035 — frequently asked
What is C68800-OS035 used for?
C68800-OS035 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-OS035?
C68800-OS035 has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 545 MPa (79 ksi) — stronger than 57% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C68800-OS035 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 78% 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-OS035 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-OS035?
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-OS035 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-OS035?
C68800-OS035 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 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.