Copper Alloy C55284
UNS C55284
C55284 (Sil-Fos 15) is a silver-bearing phosphor-copper brazing filler from the copper-phosphorus family, with 15% Ag for flow and joint ductility and phosphorus that makes it self-fluxing on copper.
Reference datasheet — C55284 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
C55284 tempers and conditions
C55284 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 C55284 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FLUX-COATED | Flux-coated rod | Supply form |
PREFORM | Stamped/formed rings, washers and shapes | Supply form |
ROD | Straight-length bare brazing rod | Supply form |
STRIP | Strip / Foil | Supply form |
WIRE | Coiled/spooled bare filler wire | Supply form |
PASTE | Paste / Powder | Printing process |
What is C55284?
C55284 (Sil-Fos 15) is a silver-bearing phosphor-copper brazing filler from the copper-phosphorus family, with 15% Ag for flow and joint ductility and phosphorus that makes it self-fluxing on copper. It is chosen for copper and copper-to-brass joints in HVAC/R, electrical and instrumentation work, and is supplied as wire, rod, strip, preform, flux-coated rod and paste. As-brazed deposits reach about 275 MPa tensile with 6% elongation, 85 HB, 50 W/(m·K) and 10% IACS, with service limited to 200 °C. It must never be used on steel, cast iron or copper alloys above 10% Ni, where brittle phosphides form. C55284 has a density of 8.4 g/cm³ (0.303 lb/in³), lighter than 75% of copper alloy grades. It melts at 643°C (1,189 °F). C55284 has a tensile strength of 275 MPa (39.9 ksi), weaker than 77% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 95 GPa (13.8 Msi).
What is C55284 used for?
- copper and copper-brass pipe brazing
- HVAC/R systems
- electrical and instrumentation joints
- general copper fabrication
Limitations
- High embodied carbon — 20 kg CO₂/kg, worse than 100% of copper alloy grades
- Difficult to weld — 10/100, worse than 98% of copper alloy grades
- Low stiffness — 95 GPa (13.8 Msi), worse than 93% of copper alloy grades
- Hard to polish — 60/100, worse than 92% of copper alloy grades
- Limited ductility — 6%, worse than 89% of copper alloy grades
C55284 properties
Typical room-temperature values for C55284-AS-BRAZED; bars are the position among copper alloy grades.
Physical3
C55284 has a density of 8.4 g/cm³ (0.303 lb/in³), lighter than 75% of copper alloy grades. It melts at 643°C (1,189 °F).
Mechanical6
C55284 has a tensile strength of 275 MPa (39.9 ksi), weaker than 77% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 95 GPa (13.8 Msi).
Thermal6
C55284 is rated for continuous service to 200°C (392 °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 µm/m·K (9.44 µin/in·°F).
Electrical3
C55284 conducts electricity at 10 % IACS, worse than 74% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 86% of copper alloy grades.
Sustainability4
Producing a kilogram of C55284 takes about 270 MJ of energy and emits 20 kg of CO₂ — more than 100% of copper alloy grades. Typical recycled content is 30%.
Manufacturability6
C55284's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability not recommended (10/100); formability good (55/100).
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. C55284 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C55284
Is C55284 easy to machine?
Not a structural machining stock; excess fillet is best removed by abrasive or file since the cast deposit is hard and notch-sensitive.
Can C55284 be welded?
This is the filler itself — braze at 704–816 °C with fast, uniform heat; never apply to steel, cast iron or >10 % Ni copper alloys (brittle phosphide layer).
Can C55284 be formed, bent or molded?
Supplied drawn or rolled; wire bends into rings readily but severe cold bending of thick rod can crack the alloy — warm-form or use preforms.
C55284 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 |
|---|---|---|
| Agsilver — widens plastic range, improves ductility and flow | 14.5 – 15.5 | 15 |
| Pphosphorus — self-fluxing agent on copper | 4.8 – 5.2 | 5 |
| Other (total)sum of unspecified elements per AWS A5.8 | ≤ 0.15 | |
| Cu | balance |
What surface finishes work on C55284?
Joints clean up with mild acid or citric flux-residue rinse; the silvery fillet takes plating (Ni/Sn) and polishing, but avoid sulfur-bearing polish compounds that tarnish it.
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).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C55284 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Sil-Fos 15
How much does C55284 cost?
C55284 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C55284 — frequently asked
What is C55284 used for?
C55284 is typically used for copper and copper-brass pipe brazing, HVAC/R systems, electrical and instrumentation joints and general copper fabrication. In short: self-fluxing on copper; highest-silver phosphor-copper filler; not for steel or high-Ni alloys.
What is the tensile strength of C55284?
C55284 has a typical tensile strength of 275 MPa (39.9 ksi) — weaker than 77% of copper alloy grades.
Is C55284 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% of copper alloy grades). Not a structural machining stock; excess fillet is best removed by abrasive or file since the cast deposit is hard and notch-sensitive.
Can C55284 be welded?
Not readily — weldability is rated not recommended (10/100). This is the filler itself — braze at 704–816 °C with fast, uniform heat; never apply to steel, cast iron or >10 % Ni copper alloys (brittle phosphide layer).
What surface finishes work on C55284?
Joints clean up with mild acid or citric flux-residue rinse; the silvery fillet takes plating (Ni/Sn) and polishing, but avoid sulfur-bearing polish compounds that tarnish it.
Can C55284 be formed, bent or molded?
Supplied drawn or rolled; wire bends into rings readily but severe cold bending of thick rod can crack the alloy — warm-form or use preforms.
What is the maximum service temperature of C55284?
C55284 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does C55284 cost?
C55284 is a high-cost copper alloy ($$$$), 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 (BCuP-5) — American Welding Society (2019)
- ASTM B260 — Standard Specification for Brazing Filler Metal — ASTM International (2020)
- GB/T 6418 (BCu80AgP) — SAC / (2008)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- Sil-Fos 15 (BCuP-5) brazing alloy datasheet — Lucas-Milhaupt / Handy & Harman (2022)
- CDA copper alloy designation C55284 — Copper Development Association (2023)
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.