Precious Metal BAg-8
GB BAg72Cu
BAg-8 (UNS P07720, BAg72Cu) is the binary silver-copper eutectic brazing filler metal, with a single sharp melting point and no mushy range.
Reference datasheet — BAg-8 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 Annealed condition
BAg-8 tempers and conditions
BAg-8 is supplied in 3 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-brazed joint deposit (cast eutectic structure) | Use these as-solidified eutectic values (lamellar Ag-rich/Cu-rich phases, 330 MPa, 12% elongation, 355 W/m·K, 400 °C max) when assessing the finished joint rather than the supplied filler. | 140 | 330 | 12 | 84 HB | 85 % IACS |
AnnealedDefault soft wire / rod / strip as supplied | Default stocked form: soft wire, rod or strip at 380 MPa tensile and 20% elongation, easy to bend into preformed rings and hand-feed, but too limp for automatic feeders. | 160 | 380 | 20 | 65 HB | 87 % IACS |
Hard drawn | Pick hard-drawn wire when an automatic feeder or stamping blank needs stiffness: 620 MPa tensile and 130 HB, with elongation dropping to 4% and formability limited. | 480 | 620 | 4 | 130 HB | 84 % IACS |
Supply forms, finishes and certifications
Ways BAg-8 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Foil-Preform | Foil / stamped preform | Supply form |
POWDER-PASTE | Atomized powder / brazing paste | Supply form |
What is BAg-8?
BAg-8 (UNS P07720, BAg72Cu) is the binary silver-copper eutectic brazing filler metal, with a single sharp melting point and no mushy range. Its zinc-free composition suits furnace and vacuum brazing of carbide tooling and electronic assemblies, and it is stocked as annealed and hard wire, foil preforms, powder paste and flux-coated forms. Typical values are 160 MPa yield, 380 MPa tensile, 20 % elongation, 65 HB and 87 % IACS, with machinability 55 and formability 85. Brazing at 800–870 °C is higher than zinc-bearing grades such as BAg-7, so heat-sensitive base metals need a lower-melting alternative. BAg-8 has a density of 10 g/cm³ (0.361 lb/in³), lighter than 65% of precious metal grades. It melts at 780°C (1,436 °F). BAg-8 has a yield strength of 160 MPa (23.2 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 66% of precious metal grades. Elongation at break is 20% and the elastic modulus is 90 GPa (13.1 Msi).
What is BAg-8 used for?
- carbide tool tip brazing
- vacuum furnace brazing
- electronic and RF component assembly
Advantages
- High electrical conductivity — 87 % IACS, better than 93% of precious metal grades
- Conducts heat well — 355 W/m·K (205.1 BTU/hr·ft·°F), better than 92% of precious metal grades
- Easy to machine — 55/100, better than 86% of precious metal grades
Limitations
- Limited ductility — 20%, worse than 77% of precious metal grades
BAg-8 properties
Typical room-temperature values for BAg-8-Annealed; bars are the position among precious metal grades.
Physical3
BAg-8 has a density of 10 g/cm³ (0.361 lb/in³), lighter than 65% of precious metal grades. It melts at 780°C (1,436 °F).
Mechanical13
BAg-8 has a yield strength of 160 MPa (23.2 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 66% of precious metal grades. Elongation at break is 20% and the elastic modulus is 90 GPa (13.1 Msi).
Thermal6
BAg-8 is rated for continuous service to 400°C (752 °F). It conducts heat at 355 W/m·K (205.1 BTU/hr·ft·°F), better than 92% of precious metal grades. Thermal expansion is 19.6 µm/m·K (10.9 µin/in·°F).
Electrical3
BAg-8 conducts electricity at 87 % IACS, better than 93% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 66% of precious metal grades.
Sustainability4
Producing a kilogram of BAg-8 takes about 1,100 MJ of energy and emits 78 kg of CO₂ — less than 71% of precious metal grades. Typical recycled content is 45%.
Manufacturability7
BAg-8's machinability is good (55/100, better than 86% of precious metal grades); weldability poor (30/100); formability excellent (85/100).
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 precious metal family
Yield strength against density for every precious metal grade FabDigit runs. BAg-8 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BAg-8
Is BAg-8 easy to machine?
Soft and gummy: turning preforms requires sharp, high-rake tooling, high spindle speed and ample lubricant to prevent smearing and built-up edge.
Can BAg-8 be welded?
This is a brazing filler metal. Furnace or vacuum braze at roughly 800–870 °C; the eutectic has no mushy range, so heat quickly and uniformly and avoid long soaks that soften the base metal.
Can BAg-8 be formed, bent or molded?
Annealed material is ductile enough to draw to wire, roll to foil and stamp into rings and shims. After hard drawing, interanneal at about 600 °C with a rapid cool to restore ductility.
BAg-8 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 |
|---|---|---|
| AgAWS A5.8/A5.8M, UNS P07720 | 71 – 73 | 72 |
| Znimpurity | ≤ 0.05 | |
| Cdcadmium-free grade | ≤ 0.01 | |
| Pimpurity | ≤ 0.01 | |
| Pbimpurity | ≤ 0.03 | |
| Other (total)sum of other elements | ≤ 0.15 | |
| Cu | balance |
What surface finishes work on BAg-8?
Pickle joints after brazing to remove flux residue. The copper-rich phase darkens in sulphide atmospheres, so plate cosmetic joints with nickel or rhodium.
Equivalent designations
Standards and trade names that resolve to Precious Metal BAg-8 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GB (China)
- BAg72Cu
- Also called
- AWS BAg-872Ag28Cu
- Other
- Ag72Cu
- Similar grades
- P07720
How much does BAg-8 cost?
BAg-8 is a high-cost precious metal ($$$$), 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.
BAg-8 — frequently asked
What is BAg-8 used for?
BAg-8 is typically used for carbide tool tip brazing, vacuum furnace brazing and electronic and RF component assembly. In short: eutectic, single melting point; zinc-free vacuum brazing filler; 87 % IACS conductivity.
What is the yield strength of BAg-8?
BAg-8 has a typical yield strength of 160 MPa (23.2 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 66% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is BAg-8 easy to machine?
Reasonably — machinability is rated good (55/100, better than 86% of precious metal grades). Soft and gummy: turning preforms requires sharp, high-rake tooling, high spindle speed and ample lubricant to prevent smearing and built-up edge.
Can BAg-8 be welded?
Not readily — weldability is rated poor (30/100). This is a brazing filler metal. Furnace or vacuum braze at roughly 800–870 °C; the eutectic has no mushy range, so heat quickly and uniformly and avoid long soaks that soften the base metal.
What surface finishes work on BAg-8?
Pickle joints after brazing to remove flux residue. The copper-rich phase darkens in sulphide atmospheres, so plate cosmetic joints with nickel or rhodium.
Can BAg-8 be formed, bent or molded?
Annealed material is ductile enough to draw to wire, roll to foil and stamp into rings and shims. After hard drawing, interanneal at about 600 °C with a rapid cool to restore ductility.
What is the maximum service temperature of BAg-8?
BAg-8 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BAg-8 Annealed and BAg-8 Hard?
Annealed is the default condition — default stocked form: soft wire, rod or strip at 380 MPa tensile and 20% elongation, easy to bend into preformed rings and hand-feed, but too limp for automatic feeders. Hard: pick hard-drawn wire when an automatic feeder or stamping blank needs stiffness: 620 MPa tensile and 130 HB, with elongation dropping to 4% and formability limited. Yield strength is 160 MPa in Annealed versus 480 MPa in Hard.
How much does BAg-8 cost?
BAg-8 is a high-cost precious metal ($$$$), 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 10046 (2018)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys — ASM International (1990)
- Silver brazing filler metal data (72Ag-28Cu eutectic) — Lucas-Milhaupt / Handy & Harman (2020)
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.