Precious Metal BVAu-5 AS-BRAZED
Heat-treated state
UNS P00307
Condition to quote for joint design allowables after furnace brazing at ~900–960 °C.
Values for the AS-BRAZED condition
What is BVAu-5 AS-BRAZED?
BVAu-5 AS-BRAZED is BVAu-5 heat treated to AS-BRAZED — condition to quote for joint design allowables after furnace brazing at ~900–960 °C. BVAu-5 AS-BRAZED has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 68% of precious metal grades. Elongation at break is 20% and the elastic modulus is 95 GPa (13.8 Msi). BVAu-5 AS-BRAZED has a density of 11.3 g/cm³ (0.408 lb/in³), heavier than 59% of precious metal grades. It melts at 845°C (1,553 °F).
Advantages
- Polishes to a fine finish — 95/100, better than 86% of precious metal grades
- High service temperature — 500°C (932 °F), better than 79% of precious metal grades
Limitations
- Limited ductility — 20%, worse than 77% of precious metal grades
BVAu-5 AS-BRAZED properties
Typical room-temperature values for BVAu-5 AS-BRAZED; 5 are specific to this condition. Other listed values are BVAu-5 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
BVAu-5 AS-BRAZED has a density of 11.3 g/cm³ (0.408 lb/in³), heavier than 59% of precious metal grades. It melts at 845°C (1,553 °F).
Mechanical10
BVAu-5 AS-BRAZED has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 68% of precious metal grades. Elongation at break is 20% and the elastic modulus is 95 GPa (13.8 Msi).
Thermal6
BVAu-5 AS-BRAZED is rated for continuous service to 500°C (932 °F). It conducts heat at 75 W/m·K (43.3 BTU/hr·ft·°F), worse than 57% of precious metal grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
BVAu-5 AS-BRAZED conducts electricity at 19 % IACS, worse than 51% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 56% of precious metal grades.
Sustainability4
Producing a kilogram of BVAu-5 AS-BRAZED takes about 76,000 MJ of energy and emits 5,300 kg of CO₂ — more than 64% of precious metal grades. Typical recycled content is 60%.
Manufacturability7
BVAu-5 AS-BRAZED's machinability is fair (45/100, better than 59% of precious metal grades); weldability fair (40/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BVAu-5 AS-BRAZED
Is BVAu-5 easy to machine?
Rarely machined — gummy, smearing noble alloy; use sharp carbide/HSS tools, high rake and light cuts, and capture all chips for refining.
Can BVAu-5 be welded?
Not a structural weld metal; joints are made by furnace brazing at ~900–960 °C in high vacuum or dry hydrogen with no flux.
Can BVAu-5 be formed, bent or molded?
Very ductile: cold rolls to thin foil and draws to fine wire with interanneals at 550–650 °C in a clean reducing atmosphere.
What surface finishes work on BVAu-5?
Leave as-brazed for vacuum service; degrease with residue-free solvents only, and avoid sulphur-bearing polishing compounds that tarnish the Ag/Cu phases.
BVAu-5 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 |
|---|---|---|
| Augold content of the ~30 % Au Au-Ag-Cu filler | 29.5 – 30.5 | 30 |
| Ag | 32 – 34 | 33 |
| Cdvacuum-grade restriction on volatile/outgassing elements | ≤ 0 | |
| Znvacuum-grade restriction | ≤ 0 | |
| Pvacuum-grade restriction | ≤ 0 | |
| Pbvacuum-grade restriction | ≤ 0 | |
| Other elements, totaltotal residuals | ≤ 0.15 | |
| Cubalance, nominally ~37 % | balance |
BVAu-5 AS-BRAZED — frequently asked
What is BVAu-5 AS-BRAZED used for?
BVAu-5 AS-BRAZED is typically used for vacuum tube sealing, sapphire/metal hermetic joints, aerospace instrument brazing and microwave device assembly. In short: most ductile BVAu grade; lower-temperature gold braze; UHV hermetic sealing filler.
What is the yield strength of BVAu-5 AS-BRAZED?
BVAu-5 AS-BRAZED has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 68% of precious metal grades.
Is BVAu-5 AS-BRAZED easy to machine?
Reasonably — machinability is rated fair (45/100, better than 59% of precious metal grades). Rarely machined — gummy, smearing noble alloy; use sharp carbide/HSS tools, high rake and light cuts, and capture all chips for refining.
Can BVAu-5 AS-BRAZED be welded?
With care — weldability is rated fair (40/100). Not a structural weld metal; joints are made by furnace brazing at ~900–960 °C in high vacuum or dry hydrogen with no flux.
What surface finishes work on BVAu-5 AS-BRAZED?
Leave as-brazed for vacuum service; degrease with residue-free solvents only, and avoid sulphur-bearing polishing compounds that tarnish the Ag/Cu phases.
Can BVAu-5 AS-BRAZED be formed, bent or molded?
Very ductile: cold rolls to thin foil and draws to fine wire with interanneals at 550–650 °C in a clean reducing atmosphere.
What is the maximum service temperature of BVAu-5 AS-BRAZED?
BVAu-5 AS-BRAZED is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- AWS A5.8M/A5.8 — Specification for Filler Metals for Brazing and Braze Welding (BAu / BVAu classifications) — American Welding Society (2019)
- ASM Handbook Vol. 6 — Welding, Brazing, and Soldering (gold-base brazing filler metals) — ASM International (1993)
- ASM Handbook Vol. 2 — Properties of Precious Metals and Alloys — ASM International (1990)
- Vacuum-grade gold braze alloy foils, wires and preforms — Morgan Advanced Materials (Wesgo Metals) / Materion (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.