Copper Alloy C55280
UNS C55280
C55280 is a copper-phosphorus brazing filler with about 5 % silver and roughly 7 % phosphorus, giving better flow and joint ductility than straight phos-copper while remaining self-fluxing on copper.
Reference datasheet — C55280 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 AS-BRAZED condition
C55280 tempers and conditions
C55280 is supplied in one standard condition, AS-BRAZED. AS-BRAZED is the default FabDigit quotes; the values on this page are for it.
Supply forms, finishes and certifications
Ways C55280 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
PREFORM | Rings, washers and stamped preforms | Supply form |
ROD | Extruded / drawn bare rod | Supply form |
STRIP | Flat strip / shim stock | Supply form |
WIRE | Coiled wire / spooled filler | Supply form |
PASTE | Atomised powder / brazing paste | Printing process |
What is C55280?
C55280 is a copper-phosphorus brazing filler with about 5 % silver and roughly 7 % phosphorus, giving better flow and joint ductility than straight phos-copper while remaining self-fluxing on copper. It is used for torch, induction and furnace brazing at approximately 720–815 °C and is supplied as rod, wire, strip, stamped preforms and paste; as-brazed properties are about 250 MPa tensile strength, 5 % elongation, 90 HB, 10 % IACS and service to 150 °C. Brass and bronze joints require flux, and the alloy must not be used on steel, stainless or nickel alloys. Silver-free C55181 is the lower-cost alternative where flow demands are modest. C55280 has a density of 8.15 g/cm³ (0.294 lb/in³), lighter than 86% of copper alloy grades. It melts at 643°C (1,189 °F). C55280 has a tensile strength of 250 MPa (36.3 ksi), weaker than 81% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 100 GPa (14.5 Msi).
What is C55280 used for?
- copper pipe brazing
- refrigeration and AC lines
- electrical connectors
Limitations
- Hard to polish — 50/100, worse than 99% of copper alloy grades
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
- Difficult to weld — 15/100, worse than 94% of copper alloy grades
- Limited ductility — 5%, worse than 93% of copper alloy grades
- High embodied carbon — 6 kg CO₂/kg, worse than 92% of copper alloy grades
C55280 properties
Typical room-temperature values for C55280-AS-BRAZED; bars are the position among copper alloy grades.
Physical3
C55280 has a density of 8.15 g/cm³ (0.294 lb/in³), lighter than 86% of copper alloy grades. It melts at 643°C (1,189 °F).
Mechanical7
C55280 has a tensile strength of 250 MPa (36.3 ksi), weaker than 81% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
C55280 is rated for continuous service to 150°C (302 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), worse than 66% of copper alloy grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
C55280 conducts electricity at 10 % IACS, worse than 74% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 68% of copper alloy grades.
Sustainability4
Producing a kilogram of C55280 takes about 90 MJ of energy and emits 6 kg of CO₂ — more than 93% of copper alloy grades. Typical recycled content is 30%.
Manufacturability7
C55280's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability poor (15/100); formability poor (25/100).
Common Calculations4
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. C55280 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C55280
Is C55280 easy to machine?
Not a structural machining alloy — the ~7 % P makes it hard and brittle; filler shapes are extruded, drawn or cast to size rather than machined.
Can C55280 be welded?
Used as the filler itself: torch, induction or furnace brazed at roughly 720–815 °C, self-fluxing on copper but requiring flux on brass and bronze.
Can C55280 be formed, bent or molded?
Limited cold ductility; supplied as extruded rod, drawn wire, strip or stamped preforms with intermediate anneals, and cannot be sharply bent.
C55280 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 |
|---|---|---|
| Ag | 1.8 – 2.2 | 2 |
| P | 6.8 – 7.2 | 7 |
| Other (total)total of all other elements per AWS A5.8 | ≤ 0.15 | |
| Cu | balance |
What surface finishes work on C55280?
Joints are cleaned of residue and can be plated or painted like copper; avoid sulfur-bearing pickles that attack the phosphide phase.
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 C55280 cost?
C55280 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C55280 — frequently asked
What is C55280 used for?
C55280 is typically used for copper pipe brazing, refrigeration and AC lines and electrical connectors. In short: 5 % silver phos-copper; better flow than plain phos-copper; self-fluxing on copper.
What is the tensile strength of C55280?
C55280 has a typical tensile strength of 250 MPa (36.3 ksi) — weaker than 81% of copper alloy grades.
Is C55280 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Not a structural machining alloy — the ~7 % P makes it hard and brittle; filler shapes are extruded, drawn or cast to size rather than machined.
Can C55280 be welded?
Not readily — weldability is rated poor (15/100). Used as the filler itself: torch, induction or furnace brazed at roughly 720–815 °C, self-fluxing on copper but requiring flux on brass and bronze.
What surface finishes work on C55280?
Joints are cleaned of residue and can be plated or painted like copper; avoid sulfur-bearing pickles that attack the phosphide phase.
Can C55280 be formed, bent or molded?
Limited cold ductility; supplied as extruded rod, drawn wire, strip or stamped preforms with intermediate anneals, and cannot be sharply bent.
What is the maximum service temperature of C55280?
C55280 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does C55280 cost?
C55280 is a high-cost copper alloy ($$$$), 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 — American Welding Society (2019)
- GB/T 6418 (2008)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering — ASM International (1993)
- UNS C55280 copper alloy record — Copper Development Association (copper.org) (2024)
- Silver-bearing phos-copper brazing alloy datasheets (Lucas-Milhaupt / Harris / ) — various filler metal producers (2024)
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.