Copper Alloy C68000
UNS C68000
C68000 is a manganese-bronze type copper-zinc braze-welding filler with iron and manganese additions for strength.
Reference datasheet — C68000 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the AW condition
C68000 tempers and conditions
C68000 is supplied in 2 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
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 |
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 |
Supply forms, finishes and certifications
Ways C68000 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FC | Flux-coated rod deposit | Supply form |
MIG | Spooled solid wire for MIG/GMAW braze welding | Surface finish |
What is C68000?
C68000 is a manganese-bronze type copper-zinc braze-welding filler with iron and manganese additions for strength. Deposits reach about 310 MPa yield, 500 MPa tensile, 30% elongation and 130 HB (74 HRB) — higher than RBCuZn-A — which is why it is used to braze weld steel and cast iron; it is supplied as bare rod, flux-coated rod and spooled GMAW wire. Electrical conductivity is 24% IACS, machinability rates 75, and service is limited to 200 °C. Zinc fuming demands extraction and low heat input; low-fuming RBCuZn grades are the alternative when peak deposit strength is not needed. C68000 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). C68000 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).
What is C68000 used for?
- cast iron braze welding
- structural steel repair
- tank and pipe fabrication
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 properties
Typical room-temperature values for C68000-AW; bars are the position among copper alloy grades.
Physical3
C68000 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 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 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 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 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'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. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C68000 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C68000
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.
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 |
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.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
How much does C68000 cost?
C68000 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C68000 — frequently asked
What is C68000 used for?
C68000 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?
C68000 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 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 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?
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 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?
C68000 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.
How much does C68000 cost?
C68000 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.