Precious Metal BVAg-8
UNS P07727
BVAg-8 is the vacuum-grade form of the 72Ag-28Cu eutectic braze filler (UNS P07727), made to low-vapor-pressure purity limits and free of zinc and cadmium for vacuum and controlled-atmosphere furnace brazing.
Reference datasheet — BVAg-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.
BVAg-8 tempers and conditions
BVAg-8 is supplied in one standard condition, AS-BRAZED.
Supply forms, finishes and certifications
Ways BVAg-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 | Strip / foil / ribbon | Supply form |
PREFORM | Stamped washers, rings and formed shapes | Supply form |
WIREDefault | Wire / rod | Supply form |
WIRE-HD | Wire | Supply form |
PASTE | Vacuum-grade paste | Printing process |
POWDER | Atomised powder | Printing process |
What is BVAg-8?
BVAg-8 is the vacuum-grade form of the 72Ag-28Cu eutectic braze filler (UNS P07727), made to low-vapor-pressure purity limits and free of zinc and cadmium for vacuum and controlled-atmosphere furnace brazing. Engineers select it for its sharp eutectic melt, clean flux-free flow and low outgassing in sealed assemblies; forms include annealed and hard-drawn wire, foil, stamped preforms, powder and paste. As-brazed properties are about 275 MPa tensile, 120 MPa yield, 25% elongation and 60 HB. It does not reduce tenacious chromium oxides on its own, so lithium-bearing BVAg-8b is the usual alternative for stainless and superalloy joints brazed without flux. BVAg-8 has a density of 9.9 g/cm³ (0.358 lb/in³), lighter than 70% of precious metal grades. It melts at 780°C (1,436 °F). BVAg-8 has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 76% of precious metal grades. Elongation at break is 25% and the elastic modulus is 85 GPa (12.3 Msi).
What is BVAg-8 used for?
- vacuum furnace brazing
- electron tube and sensor assemblies
- stainless steel vacuum components
Advantages
- High electrical conductivity — 87 % IACS, better than 93% of precious metal grades
- Conducts heat well — 350 W/m·K (202.2 BTU/hr·ft·°F), better than 89% of precious metal grades
Limitations
- Low strength — 120 MPa (17.4 ksi), worse than 76% of precious metal grades
BVAg-8 properties
Typical room-temperature values; bars are the position among precious metal grades.
Physical3
BVAg-8 has a density of 9.9 g/cm³ (0.358 lb/in³), lighter than 70% of precious metal grades. It melts at 780°C (1,436 °F).
Mechanical10
BVAg-8 has a yield strength of 120 MPa (17.4 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 76% of precious metal grades. Elongation at break is 25% and the elastic modulus is 85 GPa (12.3 Msi).
Thermal6
BVAg-8 is rated for continuous service to 370°C (698 °F). It conducts heat at 350 W/m·K (202.2 BTU/hr·ft·°F), better than 89% of precious metal grades. Thermal expansion is 19.7 µm/m·K (10.9 µin/in·°F).
Electrical3
BVAg-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 BVAg-8 takes about 1,200 MJ of energy and emits 110 kg of CO₂ — less than 66% of precious metal grades. Typical recycled content is 40%.
Manufacturability6
BVAg-8's machinability is fair (35/100, worse than 73% of precious metal grades); formability excellent (88/100).
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. BVAg-8 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BVAg-8
Is BVAg-8 easy to machine?
Rarely machined; the eutectic is soft and gummy — stamping or shearing of foil into preforms is preferred over turning or milling.
Can BVAg-8 be welded?
Not a structural weld filler; joint is made by vacuum or dry-hydrogen furnace brazing at 780–900 °C with 0.03–0.10 mm diametral clearance and no flux.
Can BVAg-8 be formed, bent or molded?
Excellent cold formability — drawn to fine wire, rolled to 0.05 mm foil and stamped into rings and washers with interstage annealing.
BVAg-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 |
|---|---|---|
| Ageutectic composition | 71 – 73 | 72 |
| Znvacuum-grade high-vapor-pressure limit | ≤ 0 | |
| Cdvacuum-grade high-vapor-pressure limit | ≤ 0 | |
| P | ≤ 0 | |
| Pb | ≤ 0 | |
| Other (total)total of all other elements | ≤ 0.15 | |
| Cu | balance |
What surface finishes work on BVAg-8?
Handle with clean gloves and degrease before loading; as-brazed fillets are bright and need no finishing, but sulfur-bearing atmospheres will tarnish them, so store preforms sealed.
Equivalent designations
Standards and trade names that resolve to Precious Metal BVAg-8 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P07727
- Also called
- BAg-8
How much does BVAg-8 cost?
BVAg-8 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
BVAg-8 — frequently asked
What is BVAg-8 used for?
BVAg-8 is typically used for vacuum furnace brazing, electron tube and sensor assemblies and stainless steel vacuum components. In short: eutectic 72Ag-28Cu filler; low-outgassing vacuum grade; flux-free furnace brazing.
What is the yield strength of BVAg-8?
BVAg-8 has a typical yield strength of 120 MPa (17.4 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 76% of precious metal grades.
Is BVAg-8 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 73% of precious metal grades). Rarely machined; the eutectic is soft and gummy — stamping or shearing of foil into preforms is preferred over turning or milling.
Can BVAg-8 be welded?
Not a structural weld filler; joint is made by vacuum or dry-hydrogen furnace brazing at 780–900 °C with 0.03–0.10 mm diametral clearance and no flux.
What surface finishes work on BVAg-8?
Handle with clean gloves and degrease before loading; as-brazed fillets are bright and need no finishing, but sulfur-bearing atmospheres will tarnish them, so store preforms sealed.
Can BVAg-8 be formed, bent or molded?
Excellent cold formability — drawn to fine wire, rolled to 0.05 mm foil and stamped into rings and washers with interstage annealing.
What is the maximum service temperature of BVAg-8?
BVAg-8 is rated for continuous use to about 370°C (698 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BVAg-8 cost?
BVAg-8 is a high-cost precious metal ($$$$), 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)
- ASM Handbook Vol. 6 — Welding, Brazing, and Soldering (Brazing Filler Metals) — ASM International (1993)
- Brazing Handbook, 5th ed. — American Welding Society (2007)
- Silver-copper eutectic vacuum-grade filler metal datasheets (Lucas-Milhaupt / Umicore / ) — various producers (2023)
- GB/T 10046 — SAC (2018)
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.