Precious Metal BVAu-8-ANN (Annealed)
Heat-treated state · default condition
UNS P00927
Standard stocked condition: soft, highly ductile wire/foil/preforms that conform easily into joint gaps and rings.
Values for the ANN condition
Other BVAu-8 tempers and conditions
BVAu-8 is listed in 3 conditions; see the grade overview at BVAu-8.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
solidified joint / deposit condition | Design condition for the finished vacuum-brazed joint; strength is normally limited by fillet geometry and base metal, not the filler. | 95 | 240 | 20 | 62 HB | 16 % IACS |
ANNDefaultThis page Annealed | Standard stocked condition: soft, highly ductile wire/foil/preforms that conform easily into joint gaps and rings. | 100 | 250 | 30 | 58 HB | 17 % IACS |
Cold worked | Pick when the preform must hold its shape (stiff rings, self-supporting shims, automatic feed wire). | 380 | 450 | 3 | 124 HB | 16 % IACS |
What is BVAu-8-ANN?
BVAu-8-ANN is BVAu-8 heat treated to ANN — standard stocked condition: soft, highly ductile wire/foil/preforms that conform easily into joint gaps and rings. BVAu-8-ANN has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 84% of precious metal grades. Elongation at break is 30% and the elastic modulus is 90 GPa (13.1 Msi). BVAu-8-ANN has a density of 17.85 g/cm³ (0.645 lb/in³), heavier than 88% of precious metal grades. It melts at 995°C (1,823 °F).
Advantages
- High service temperature — 800°C (1,472 °F), better than 90% of precious metal grades
- Good corrosion resistance — 95/100, better than 82% of precious metal grades
Limitations
- High embodied carbon — 15,000 kg CO₂/kg, worse than 94% of precious metal grades
- Heavy — 17.85 g/cm³ (0.645 lb/in³), worse than 88% of precious metal grades
- Difficult to machine — 30/100, worse than 86% of precious metal grades
- Low strength — 100 MPa (14.5 ksi), worse than 84% of precious metal grades
BVAu-8-ANN properties
Typical room-temperature values for BVAu-8-ANN; 17 are specific to this condition. Other listed values are BVAu-8 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
BVAu-8-ANN has a density of 17.85 g/cm³ (0.645 lb/in³), heavier than 88% of precious metal grades. It melts at 995°C (1,823 °F).
Mechanical12
BVAu-8-ANN has a yield strength of 100 MPa (14.5 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 84% of precious metal grades. Elongation at break is 30% and the elastic modulus is 90 GPa (13.1 Msi).
Thermal6
BVAu-8-ANN is rated for continuous service to 800°C (1,472 °F). It conducts heat at 150 W/m·K (86.7 BTU/hr·ft·°F), better than 65% of precious metal grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
BVAu-8-ANN conducts electricity at 17 % IACS, worse than 56% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (95/100), better than 82% of precious metal grades.
Sustainability4
Producing a kilogram of BVAu-8-ANN takes about 230,000 MJ of energy and emits 15,000 kg of CO₂ — more than 90% of precious metal grades. Typical recycled content is 70%.
Manufacturability7
BVAu-8-ANN's machinability is poor (30/100, worse than 86% of precious metal grades); formability excellent (88/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BVAu-8-ANN
Is BVAu-8 easy to machine?
Very soft and gummy — use sharp uncoated carbide/diamond tools, high speed, light feed, and capture all chips for refining.
Can BVAu-8 be welded?
Not a structural weld alloy; joined only by brazing/soldering — vacuum or dry-hydrogen furnace cycles at roughly 1020–1090 °C with 0.025–0.075 mm joint clearance.
Can BVAu-8 be formed, bent or molded?
Excellent cold formability in the annealed state: rolled to thin foil, drawn to fine wire, stamped into rings and washers with interstage anneals.
What surface finishes work on BVAu-8?
Requires no protective coating; degrease with solvent/ultrasonic clean before furnace run, and avoid touching preforms bare-handed to prevent carbon and salt contamination.
BVAu-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 |
|---|---|---|
| Auhigh-purity gold, vacuum grade | 92 – 93.5 | 92.7 |
| Cdvacuum grade — volatile elements restricted | ≤ 0 | — |
| Znvacuum grade — volatile elements restricted | ≤ 0 | — |
| Prestricted | ≤ 0 | — |
| Other elements, totalAWS A5.8 residual limit | ≤ 0.15 | — |
| Cu | balance | — |
BVAu-8-ANN — frequently asked
What is BVAu-8-ANN used for?
BVAu-8-ANN is typically used for ultra-high-vacuum device brazing, delicate electronic hermetic seals, precision sensor packaging and low-temperature vacuum joints. In short: narrow low melting range; minimal base-metal alloying; best-forming gold braze filler.
What is the yield strength of BVAu-8-ANN?
BVAu-8-ANN has a typical yield strength of 100 MPa (14.5 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 84% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is BVAu-8-ANN easy to machine?
Not especially — machinability is rated poor (30/100, worse than 86% of precious metal grades). Very soft and gummy — use sharp uncoated carbide/diamond tools, high speed, light feed, and capture all chips for refining.
Can BVAu-8-ANN be welded?
Not a structural weld alloy; joined only by brazing/soldering — vacuum or dry-hydrogen furnace cycles at roughly 1020–1090 °C with 0.025–0.075 mm joint clearance.
What surface finishes work on BVAu-8-ANN?
Requires no protective coating; degrease with solvent/ultrasonic clean before furnace run, and avoid touching preforms bare-handed to prevent carbon and salt contamination.
Can BVAu-8-ANN be formed, bent or molded?
Excellent cold formability in the annealed state: rolled to thin foil, drawn to fine wire, stamped into rings and washers with interstage anneals.
What is the maximum service temperature of BVAu-8-ANN?
BVAu-8-ANN is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BVAu-8-ANN and BVAu-8 Hard?
ANN is the default condition — standard stocked condition: soft, highly ductile wire/foil/preforms that conform easily into joint gaps and rings. Hard: pick when the preform must hold its shape (stiff rings, self-supporting shims, automatic feed wire). Yield strength is 100 MPa in ANN versus 380 MPa in Hard.
Sources
- AWS A5.8M/A5.8 Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- ASM Handbook Vol. 6: Welding, Brazing and Soldering — Gold Brazing Filler Metals — ASM International (1993)
- ASM Handbook Vol. 2: Properties of Nonferrous Alloys — Gold and Gold Alloys — ASM International (1990)
- Vacuum-grade gold braze filler metals (wire, foil, preforms) — Morgan Advanced Materials / Wesgo Metals (2022)
- UNS Metals & Alloys in the Unified Numbering System (P00927) — SAE/ASTM (2017)
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.