Copper Alloy C68400-O61
Heat-treated state
UNS C68400
O61 = annealed
Pick when maximum ductility for bending, spinning or deep drawing is needed before final forming.
Values for the O61 condition
Other C68400 tempers and conditions
C68400 is listed in 9 conditions; see the grade overview at C68400.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O61This page Annealed | Pick when maximum ductility for bending, spinning or deep drawing is needed before final forming. | 200 | 460 | 32 | 100 HB | 15 % IACS |
As hot rolled | Pick for hot-rolled plate/flats where strength requirements are modest and further machining follows. | 230 | 480 | 28 | 115 HB | 15 % IACS |
As hot extruded | Standard condition for large-diameter rod, hollows and shapes; best hot-worked ductility, lowest cold-work stresses. | 250 | 500 | 26 | 120 HB | 15 % IACS |
Quarter hard | Light cold draw for straight, close-tolerance rod that still needs to be bent or headed. | 290 | 530 | 24 | 135 HB | 14.5 % IACS |
Light drawn | Light-drawn tube temper for hollow marine fittings that still need bending or expanding. | 300 | 540 | 22 | 140 HB | 15 % IACS |
H02Default Half hard | Default stocked rod/bar temper — best balance of strength, straightness and machinability for marine hardware and fasteners. | 340 | 570 | 20 | 150 HB | 14.5 % IACS |
Cold drawn and stress relieved | Choose when residual stresses must be lowered to resist stress-corrosion cracking in ammonia or marine service. | 350 | 560 | 20 | 150 HB | 15 % IACS |
Full hard | Pick for maximum strength and wear resistance in shafts, valve stems and bushings with little further forming. | 450 | 650 | 12 | 180 HB | 14 % IACS |
Extra hard | Heavily drawn small-diameter rod/wire for springy or high-load fastener applications; very limited ductility. | 540 | 720 | 8 | 200 HB | 14 % IACS |
What is C68400-O61?
C68400-O61 is C68400 heat treated to O61 — pick when maximum ductility for bending, spinning or deep drawing is needed before final forming. C68400-O61 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 54% of copper alloy grades. Elongation at break is 32% and the elastic modulus is 103 GPa (14.9 Msi). C68400-O61 has a density of 8.35 g/cm³ (0.302 lb/in³), lighter than 77% of copper alloy grades. It melts at 865°C (1,589 °F). H02 is the default condition FabDigit quotes; O61 is available on request or by drawing note.
Advantages
- Forms and bends easily — 65/100, better than 78% of copper alloy grades
- Ductile — tolerates forming and impact — 32%, better than 77% of copper alloy grades
C68400-O61 properties
Typical room-temperature values for C68400-O61; 20 are specific to this condition. Other listed values are C68400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C68400-O61 has a density of 8.35 g/cm³ (0.302 lb/in³), lighter than 77% of copper alloy grades. It melts at 865°C (1,589 °F).
Mechanical14
C68400-O61 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 54% of copper alloy grades. Elongation at break is 32% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C68400-O61 is rated for continuous service to 200°C (392 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), worse than 73% of copper alloy grades. Thermal expansion is 20.5 µm/m·K (11.4 µin/in·°F).
Electrical3
C68400-O61 conducts electricity at 15 % IACS, worse than 54% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C68400-O61 takes about 50 MJ of energy and emits 3.4 kg of CO₂ — less than 89% of copper alloy grades. Typical recycled content is 50%.
Manufacturability8
C68400-O61's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability fair (45/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68400-O61
Is C68400 easy to machine?
Machines like unleaded high-strength brass (~30 % of AISI 1212): use sharp, positive-rake carbide, high speed with light feeds, and copious coolant to avoid gummy chips and built-up edge.
Can C68400 be welded?
Fusion welding is restricted by zinc fuming and porosity; prefer brazing, silver soldering or GTAW with silicon-bronze filler, low heat input and good extraction.
Can C68400 be formed, bent or molded?
Best hot worked at ~650–750 °C (extrusion, forging); cold formability is limited by the hard silicide phase, so allow interanneals at ~500–600 °C between draws.
What surface finishes work on C68400?
Polishes and buffs well and takes Ni/Cr or decorative electroplate readily; anodizing is not applicable — protect with clear lacquer or chemical patina, and stress-relieve before service in ammonia-bearing atmospheres.
C68400 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 |
|---|---|---|
| CuCu-Zn α+β matrix; exact registry limits should be confirmed against the governing standard | 55 – 60 | 57.5 |
| Siforms hard Cu-Zn-Si silicide phase for strength/wear | 0.5 – 1.5 | 1 |
| Mnsolid-solution and Mn-Si intermetallic strengthening | 1.5 – 3 | 2 |
| Fegrain refiner / impurity limit | ≤ 0.5 | 0.2 |
| Al | ≤ 0.5 | 0.2 |
| Sn | ≤ 0.5 | — |
| Pbkept low; not a free-cutting grade | ≤ 0.2 | — |
| Zn | balance | — |
C68400-O61 — frequently asked
What is C68400-O61 used for?
C68400-O61 is typically used for marine hardware, heavy-duty fasteners and structural components. In short: high-strength silicon brass; marine fastener grade; limited cold formability.
What is the yield strength of C68400-O61?
C68400-O61 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 54% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C68400-O61 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Machines like unleaded high-strength brass (~30 % of AISI 1212): use sharp, positive-rake carbide, high speed with light feeds, and copious coolant to avoid gummy chips and built-up edge.
Can C68400-O61 be welded?
With care — weldability is rated fair (45/100). Fusion welding is restricted by zinc fuming and porosity; prefer brazing, silver soldering or GTAW with silicon-bronze filler, low heat input and good extraction.
What surface finishes work on C68400-O61?
Polishes and buffs well and takes Ni/Cr or decorative electroplate readily; anodizing is not applicable — protect with clear lacquer or chemical patina, and stress-relieve before service in ammonia-bearing atmospheres.
Can C68400-O61 be formed, bent or molded?
Best hot worked at ~650–750 °C (extrusion, forging); cold formability is limited by the hard silicide phase, so allow interanneals at ~500–600 °C between draws.
What is the maximum service temperature of C68400-O61?
C68400-O61 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 C68400-H02 and C68400-H06?
H02 is the default condition — default stocked rod/bar temper — best balance of strength, straightness and machinability for marine hardware and fasteners. H06: heavily drawn small-diameter rod/wire for springy or high-load fastener applications; very limited ductility. Yield strength is 340 MPa in H02 versus 540 MPa in H06.
Sources
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (wrought brass section) — ASM International (1990)
- ASTM B36/B124/B927 — wrought brass rod, bar, shapes and temper designations (ASTM B601) — ASTM International (2020)
- CDA/UNS copper alloy designation listings (C6xxxx high-strength brasses) — Copper Development Association (2023)
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.