Copper Alloy C68000-AW (As-welded deposit)
Heat-treated state · default condition
UNS C68000
Default condition: properties of the as-deposited braze weld metal made with bare RBCuZn-B rod plus separate flux.
Values for the AW 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 |
|---|---|---|---|---|---|---|
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 |
AWDefaultThis page 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-AW?
C68000-AW is C68000 heat treated to AW — default condition: properties of the as-deposited braze weld metal made with bare RBCuZn-B rod plus separate flux. C68000-AW has a yield strength of 310 MPa (45 ksi) and a tensile strength of 500 MPa (72.5 ksi) — stronger than 64% of copper alloy grades. Elongation at break is 30% and the elastic modulus is 103 GPa (14.9 Msi). C68000-AW 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).
Advantages
- Low embodied carbon — 3.2 kg CO₂/kg, better than 92% of copper alloy grades
- Easy to machine — 75/100, better than 80% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
- Ductile — tolerates forming and impact — 30%, better than 75% of copper alloy grades
C68000-AW properties
Typical room-temperature values for C68000-AW; 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-AW 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-AW has a yield strength of 310 MPa (45 ksi) and a tensile strength of 500 MPa (72.5 ksi) — stronger than 64% of copper alloy grades. Elongation at break is 30% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C68000-AW is rated for continuous service to 200°C (392 °F). It conducts heat at 120 W/m·K (69.3 BTU/hr·ft·°F), better than 66% of copper alloy grades. Thermal expansion is 20.8 µm/m·K (11.6 µin/in·°F).
Electrical3
C68000-AW conducts electricity at 24 % IACS, better than 57% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 86% of copper alloy grades.
Sustainability4
Producing a kilogram of C68000-AW 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-AW's machinability is very good (75/100, better than 80% of copper alloy grades); weldability good (60/100); formability fair (50/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C68000-AW
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-AW — frequently asked
What is C68000-AW used for?
C68000-AW 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-AW?
C68000-AW has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 500 MPa (72.5 ksi) — stronger than 64% of copper alloy grades. Strength varies by condition: see the 2 listed tempers.
Is C68000-AW easy to machine?
Yes — machinability is rated very good (75/100, better than 80% 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-AW be welded?
Yes — weldability is rated good (60/100). 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-AW?
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-AW 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-AW?
C68000-AW 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.