Copper Alloy BCu-2
UNS C81100 · GB BCu100
BCu-2 is a high-purity copper brazing filler metal in the BCu family (also listed as C81100 and BCu100), supplied as paste and powder for furnace and torch brazing of steel and copper assemblies that need an oxygen-free deposit.
Reference datasheet — BCu-2 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
BCu-2 tempers and conditions
BCu-2 is supplied in 2 conditions, soft to hard. AS-BRAZED 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 used when the deposit is evaluated as bulk cast copper (test castings, filler slugs). | 62 | 172 | 40 | 44 HB | 92 % IACS |
AS-BRAZEDDefault reduced copper joint/deposit after furnace brazing | Default condition: the essentially pure copper metal left in the joint after the oxide paste is reduced at 1090–1150 °C in hydrogen or dissociated ammonia. | 65 | 200 | 35 | 45 HB | 90 % IACS |
Supply forms, finishes and certifications
Ways BCu-2 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
PASTE | Copper oxide dispersed in organic vehicle | Printing process |
POWDER | Copper/copper-oxide powder for paste making or preform pressing | Printing process |
What is BCu-2?
BCu-2 is a high-purity copper brazing filler metal in the BCu family (also listed as C81100 and BCu100), supplied as paste and powder for furnace and torch brazing of steel and copper assemblies that need an oxygen-free deposit. It is the companion product to BCu-1, and the as-brazed deposit is essentially pure copper at roughly 200 MPa tensile, 65 MPa yield, 35 % elongation and 45 HB, with 346 W/m·K thermal conductivity and 90 % IACS. The limits are the soft, low-strength fillet, a 350 °C service ceiling, and remelting of the joint if it is reheated above about 1080 °C. BCu-2 has a density of 8.92 g/cm³ (0.322 lb/in³), heavier than 81% of copper alloy grades. It melts at 1,083°C (1,981 °F). BCu-2 has a yield strength of 65 MPa (9.43 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 98% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 115 GPa (16.7 Msi).
What is BCu-2 used for?
- furnace brazing of steel joints
- heat exchanger fin brazing
- copper-to-steel joints
- hydrogen-atmosphere brazing
Advantages
- Tough — resists crack growth — 90 MPa·√m (81.9 ksi·√in), better than 96% of copper alloy grades
- High service temperature — 350°C (662 °F), better than 95% of copper alloy grades
- Forms and bends easily — 90/100, better than 89% of copper alloy grades
- Conducts heat well — 346 W/m·K (199.9 BTU/hr·ft·°F), better than 87% of copper alloy grades
- High electrical conductivity — 90 % IACS, better than 87% of copper alloy grades
Limitations
- Low strength — 65 MPa (9.43 ksi), worse than 98% of copper alloy grades
- Difficult to machine — 25/100, worse than 86% of copper alloy grades
BCu-2 properties
Typical room-temperature values for BCu-2-AS-BRAZED; bars are the position among copper alloy grades.
Physical3
BCu-2 has a density of 8.92 g/cm³ (0.322 lb/in³), heavier than 81% of copper alloy grades. It melts at 1,083°C (1,981 °F).
Mechanical15
BCu-2 has a yield strength of 65 MPa (9.43 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 98% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
BCu-2 is rated for continuous service to 350°C (662 °F). It conducts heat at 346 W/m·K (199.9 BTU/hr·ft·°F), better than 87% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
BCu-2 conducts electricity at 90 % IACS, better than 87% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of BCu-2 takes about 50 MJ of energy and emits 3.8 kg of CO₂ — less than 89% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
BCu-2's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability fair (45/100); formability excellent (90/100).
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. BCu-2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BCu-2
Is BCu-2 easy to machine?
Deposit is soft, gummy pure copper — use sharp positive-rake tools, high speed, generous coolant; expect burrs and poor chip breaking.
Can BCu-2 be welded?
Not a structural weld metal; joints are made by furnace/torch brazing at 1090–1150 °C, and re-heating a BCu joint above ~1080 °C will remelt it.
Can BCu-2 be formed, bent or molded?
Supplied as paste or powder — dispense, screen-print or press into preforms; joint clearances of 0.00–0.05 mm (interference to line-to-line) give the best capillary fill.
BCu-2 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.
| Element | Spec limit (wt %) |
|---|---|
| P | ≤ 0.08 |
| Pb | ≤ 0.02 |
| Other (total)Residuals excluding the organic vehicle and combined oxygen | ≤ 0.5 |
| CuMetallic copper content of the supplied oxide/vehicle product per AWS A5.8; the reduced deposit is essentially pure Cu | ≥ 86.5 (balance) |
What surface finishes work on BCu-2?
Bright reduced-copper fillets tarnish in air; protect with lacquer, or nickel/tin plate. Copper is not anodizable.
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 BCu-2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- C81100
- GB (China)
- BCu100
How much does BCu-2 cost?
BCu-2 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.
BCu-2 — frequently asked
What is BCu-2 used for?
BCu-2 is typically used for furnace brazing of steel joints, heat exchanger fin brazing, copper-to-steel joints and hydrogen-atmosphere brazing. In short: oxygen-free copper braze deposit; high-conductivity brazed joint; paste and powder forms.
What is the yield strength of BCu-2?
BCu-2 has a typical yield strength of 65 MPa (9.43 ksi) and a tensile strength of 200 MPa (29 ksi) — weaker than 98% of copper alloy grades. Strength varies by condition: see the 2 listed tempers.
Is BCu-2 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% of copper alloy grades). Deposit is soft, gummy pure copper — use sharp positive-rake tools, high speed, generous coolant; expect burrs and poor chip breaking.
Can BCu-2 be welded?
With care — weldability is rated fair (45/100). Not a structural weld metal; joints are made by furnace/torch brazing at 1090–1150 °C, and re-heating a BCu joint above ~1080 °C will remelt it.
What surface finishes work on BCu-2?
Bright reduced-copper fillets tarnish in air; protect with lacquer, or nickel/tin plate. Copper is not anodizable.
Can BCu-2 be formed, bent or molded?
Supplied as paste or powder — dispense, screen-print or press into preforms; joint clearances of 0.00–0.05 mm (interference to line-to-line) give the best capillary fill.
What is the maximum service temperature of BCu-2?
BCu-2 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BCu-2 AS-BRAZED and BCu-2 Cast?
AS-BRAZED is the default condition — default condition: the essentially pure copper metal left in the joint after the oxide paste is reduced at 1090–1150 °C in hydrogen or dissociated ammonia. Cast: reference condition used when the deposit is evaluated as bulk cast copper (test castings, filler slugs). Yield strength is 65 MPa in AS-BRAZED versus 62 MPa in Cast.
How much does BCu-2 cost?
BCu-2 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 — SAC (2008)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (brazing filler metals) — ASM International (1993)
- CDA alloy datasheet C81100 (cast pure copper) — 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.