Precious Metal BVAu-2-ANN (Annealed)
Heat-treated state · default condition
UNS P00807
Standard stocked condition for vacuum-brazing preforms, foil and wire where formability and clean surfaces matter.
Values for the ANN condition
Other BVAu-2 tempers and conditions
BVAu-2 is listed in 3 conditions; see the grade overview at BVAu-2.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefaultThis page Annealed | Standard stocked condition for vacuum-brazing preforms, foil and wire where formability and clean surfaces matter. | 200 | 400 | 25 | 130 HB | 15 % IACS |
As built (as printed) | Use these numbers for joint design after vacuum brazing at roughly 900–1010 °C with slow cooling. | 230 | 360 | 20 | 140 HB | 15 % IACS |
Hard drawn / as-rolled | Pick when stiffer wire or spring-back-free ring preforms are needed for automated placement; ductility is reduced. | 520 | 620 | 4 | 195 HB | 14.5 % IACS |
What is BVAu-2-ANN?
BVAu-2-ANN is BVAu-2 heat treated to ANN — standard stocked condition for vacuum-brazing preforms, foil and wire where formability and clean surfaces matter. BVAu-2-ANN has a yield strength of 200 MPa (29 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 51% of precious metal grades. Elongation at break is 25% and the elastic modulus is 92 GPa (13.3 Msi). BVAu-2-ANN has a density of 15.9 g/cm³ (0.574 lb/in³), heavier than 81% of precious metal grades. It melts at 889°C (1,632 °F).
Advantages
- Good corrosion resistance — 93/100, better than 77% of precious metal grades
Limitations
- High embodied carbon — 14,000 kg CO₂/kg, worse than 88% of precious metal grades
- Heavy — 15.9 g/cm³ (0.574 lb/in³), worse than 81% of precious metal grades
- Poor heat conductor — 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 76% of precious metal grades
BVAu-2-ANN properties
Typical room-temperature values for BVAu-2-ANN; 19 are specific to this condition. Other listed values are BVAu-2 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
BVAu-2-ANN has a density of 15.9 g/cm³ (0.574 lb/in³), heavier than 81% of precious metal grades. It melts at 889°C (1,632 °F).
Mechanical13
BVAu-2-ANN has a yield strength of 200 MPa (29 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 51% of precious metal grades. Elongation at break is 25% and the elastic modulus is 92 GPa (13.3 Msi).
Thermal6
BVAu-2-ANN is rated for continuous service to 400°C (752 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 76% of precious metal grades. Thermal expansion is 15.9 µm/m·K (8.83 µin/in·°F).
Electrical3
BVAu-2-ANN conducts electricity at 15 % IACS, worse than 65% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (93/100), better than 77% of precious metal grades.
Sustainability4
Producing a kilogram of BVAu-2-ANN takes about 200,000 MJ of energy and emits 14,000 kg of CO₂ — more than 85% of precious metal grades. Typical recycled content is 70%.
Manufacturability8
BVAu-2-ANN's machinability is fair (40/100, worse than 60% of precious metal grades); weldability good (60/100); formability excellent (90/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BVAu-2-ANN
Is BVAu-2 easy to machine?
Soft and gummy — use sharp, polished, high-rake carbide tooling, light cuts and full scrap recovery; machining is rare since preforms are stamped.
Can BVAu-2 be welded?
Not a structural weld metal; it is applied as a brazing filler at about 900–1010 °C in high vacuum or dry hydrogen, with slow ramping to avoid preform shift and outgassing.
Can BVAu-2 be formed, bent or molded?
Excellent cold formability in the annealed state — rolled to 25–100 µm foil, drawn to fine wire and stamped into washers, rings and shims with interanneals.
What surface finishes work on BVAu-2?
Parts are used bare; clean preforms with solvent/ultrasonic degrease only, avoid chlorinated or sulphur-bearing residues, and handle with clean gloves to protect vacuum cleanliness.
BVAu-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. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| AuUNS P00807 | 79.5 – 80.5 | 80 |
| Other elements, totalAWS A5.8 impurity limit; vacuum grade additionally restricts high-vapour-pressure elements (Cd, Zn, Pb, P, Mg, S) to trace levels | ≤ 0.15 | — |
| Cu | balance | — |
BVAu-2-ANN — frequently asked
What is BVAu-2-ANN used for?
BVAu-2-ANN is typically used for high-vacuum tube assemblies, satellite and spacecraft hardware, klystron and traveling-wave tube brazing and ultra-high-vacuum instrumentation. In short: vacuum-grade Au-Cu braze; low-outgassing filler; excellent cold formability.
What is the yield strength of BVAu-2-ANN?
BVAu-2-ANN has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 51% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is BVAu-2-ANN easy to machine?
Not especially — machinability is rated fair (40/100, worse than 60% of precious metal grades). Soft and gummy — use sharp, polished, high-rake carbide tooling, light cuts and full scrap recovery; machining is rare since preforms are stamped.
Can BVAu-2-ANN be welded?
Yes — weldability is rated good (60/100). Not a structural weld metal; it is applied as a brazing filler at about 900–1010 °C in high vacuum or dry hydrogen, with slow ramping to avoid preform shift and outgassing.
What surface finishes work on BVAu-2-ANN?
Parts are used bare; clean preforms with solvent/ultrasonic degrease only, avoid chlorinated or sulphur-bearing residues, and handle with clean gloves to protect vacuum cleanliness.
Can BVAu-2-ANN be formed, bent or molded?
Excellent cold formability in the annealed state — rolled to 25–100 µm foil, drawn to fine wire and stamped into washers, rings and shims with interanneals.
What is the maximum service temperature of BVAu-2-ANN?
BVAu-2-ANN 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 BVAu-2-ANN and BVAu-2-HD?
ANN is the default condition — standard stocked condition for vacuum-brazing preforms, foil and wire where formability and clean surfaces matter. HD: pick when stiffer wire or spring-back-free ring preforms are needed for automated placement; ductility is reduced. Yield strength is 200 MPa in ANN versus 520 MPa in HD.
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)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (precious metals) — ASM International (1990)
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.