Copper Alloy C68000 Cast
Grade
UNS C68000
Cast = as cast
Reference condition for thick multi-pass overlays and cast test coupons; coarser grain gives slightly lower strength and ductility than a thin braze layer.
Values for the Cast condition
Other C68000 tempers and conditions
C68000 is listed in 2 conditions; see the grade overview at C68000.
- Cast
- AW
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
CastThis page As cast | Reference condition for thick multi-pass overlays and cast test coupons; coarser grain gives slightly lower strength and ductility than a thin braze layer. | 260 | 450 | 22 | 120 HB | 24 % IACS |
AWDefault As-welded deposit | Default condition: properties of the as-deposited braze weld metal made with bare RBCuZn-B rod plus separate flux. | 310 | 500 | 30 | 130 HB | 24 % IACS |
What is C68000 Cast?
C68000 Cast is C68000 in the Cast grade — reference condition for thick multi-pass overlays and cast test coupons; coarser grain gives slightly lower strength and ductility than a thin braze layer. C68000 Cast has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 55% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 100 GPa (14.5 Msi). C68000 Cast has a density of 8.36 g/cm³ (0.302 lb/in³), lighter than 76% of copper alloy grades. It melts at 866°C (1,591 °F). AW is the default condition FabDigit quotes; Cast is available on request or by drawing note.
Advantages
- Low embodied carbon — 3.2 kg CO₂/kg, better than 92% of copper alloy grades
- Easy to machine — 78/100, better than 82% of copper alloy grades
Limitations
- Needs corrosion protection — 52/100, worse than 93% of copper alloy grades
- Low stiffness — 100 GPa (14.5 Msi), worse than 82% of copper alloy grades
C68000 Cast properties
Typical room-temperature values for C68000 Cast; 20 are specific to this condition. Other listed values are C68000 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C68000 Cast has a density of 8.36 g/cm³ (0.302 lb/in³), lighter than 76% of copper alloy grades. It melts at 866°C (1,591 °F).
Mechanical14
C68000 Cast has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 55% of copper alloy grades. Elongation at break is 22% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
C68000 Cast is rated for continuous service to 200°C (392 °F). It conducts heat at 118 W/m·K (68.2 BTU/hr·ft·°F), better than 65% of copper alloy grades. Thermal expansion is 20.8 µm/m·K (11.6 µin/in·°F).
Electrical3
C68000 Cast conducts electricity at 24 % IACS, better than 57% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 93% of copper alloy grades.
Sustainability4
Producing a kilogram of C68000 Cast takes about 52 MJ of energy and emits 3.2 kg of CO₂ — less than 87% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C68000 Cast's machinability is very good (78/100, better than 82% of copper alloy grades); weldability good (58/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68000 Cast
Is C68000 easy to machine?
Deposit machines like a high-strength unleaded brass — use sharp positive-rake carbide, moderate speeds; expect stringy chips versus free-cutting brass.
Can C68000 be welded?
Applied by oxy-acetylene braze welding (slightly oxidising flame) or GMAW braze at 880–915 °C with borax-type flux; keep heat input low and ventilate for zinc fume.
Can C68000 be formed, bent or molded?
Supplied as drawn bare rod, flux-coated rod or spooled wire; the deposit itself is a casting and should not be relied on for cold forming.
What surface finishes work on C68000?
Colour is a yellow-gold brass tone that blends with brass/bronze bases; polishes well, can be lacquered, chemically patinated or nickel/chrome plated — not anodisable.
C68000 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 | 56 – 60 | 58 |
| Sn | 0.8 – 1.1 | 0.95 |
| Fegrain refinement, raises strength | 0.25 – 1.2 | 0.7 |
| Mn | 0.01 – 0.5 | 0.25 |
| Nidistinguishes RBCuZn-B from RBCuZn-C | 0.2 – 0.8 | 0.5 |
| Sisuppresses zinc fuming | 0.04 – 0.15 | 0.1 |
| Pb | ≤ 0.05 | — |
| Al | ≤ 0.01 | — |
| Others (total) | ≤ 0.5 | — |
| Zn | balance | — |
C68000 Cast — frequently asked
What is C68000 Cast used for?
C68000 Cast is typically used for cast iron braze welding, structural steel repair and tank and pipe fabrication. In short: strongest brass-type filler; stronger than RBCuZn-A; braze welds cast iron.
What is the yield strength of C68000 Cast?
C68000 Cast has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — stronger than 55% of copper alloy grades. Strength varies by condition: see the 2 listed tempers.
Is C68000 Cast easy to machine?
Yes — machinability is rated very good (78/100, better than 82% of copper alloy grades). Deposit machines like a high-strength unleaded brass — use sharp positive-rake carbide, moderate speeds; expect stringy chips versus free-cutting brass.
Can C68000 Cast be welded?
Yes — weldability is rated good (58/100). Applied by oxy-acetylene braze welding (slightly oxidising flame) or GMAW braze at 880–915 °C with borax-type flux; keep heat input low and ventilate for zinc fume.
What surface finishes work on C68000 Cast?
Colour is a yellow-gold brass tone that blends with brass/bronze bases; polishes well, can be lacquered, chemically patinated or nickel/chrome plated — not anodisable.
Can C68000 Cast be formed, bent or molded?
Supplied as drawn bare rod, flux-coated rod or spooled wire; the deposit itself is a casting and should not be relied on for cold forming.
What is the maximum service temperature of C68000 Cast?
C68000 Cast 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 C68000-AW and C68000 Cast?
AW is the default condition — default condition: properties of the as-deposited braze weld metal made with bare RBCuZn-B rod plus separate flux. Cast: reference condition for thick multi-pass overlays and cast test coupons; coarser grain gives slightly lower strength and ductility than a thin braze layer. Yield strength is 310 MPa in AW versus 260 MPa in Cast.
Sources
- AWS A5.8/A5.8M — Specification for Filler Metals for Brazing and Braze Welding (RBCuZn-B) — American Welding Society (2019)
- AWS A5.27/A5.27M — Specification for Copper and Copper Alloy Rods for Gas Welding — American Welding Society (2017)
- CDA Alloy C68000 (Low Fuming Brass, Nickel) datasheet — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- Low-fuming bronze braze welding rod datasheets — Harris Products Group / Lucas-Milhaupt (2022)
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.