Precious Metal BVAu-8
UNS P00927
A high-gold (~92.7%Au) vacuum-service gold-copper filler with a narrow, low melting range and minimal volatile content, used for delicate hermetic vacuum brazes where minimal alloying with the base metal is desired.
Reference datasheet — BVAu-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 ANN condition
BVAu-8 tempers and conditions
BVAu-8 is supplied in 3 conditions, soft to hard. ANN 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 |
|---|---|---|---|---|---|---|
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 |
ANNDefault 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 |
Supply forms, finishes and certifications
Ways BVAu-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 |
|---|---|---|
CAST-PREFORM | Cast / sintered preform | Supply form |
What is BVAu-8?
A high-gold (~92.7%Au) vacuum-service gold-copper filler with a narrow, low melting range and minimal volatile content, used for delicate hermetic vacuum brazes where minimal alloying with the base metal is desired. BVAu-8 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). BVAu-8 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).
What is BVAu-8 used for?
- Ultra-high-vacuum device brazing
- Delicate electronic hermetic seals
- Precision sensor packaging
- Low-temperature vacuum joints
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 properties
Typical room-temperature values for BVAu-8-ANN; bars are the position among precious metal grades.
Physical3
BVAu-8 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 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 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 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 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'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. 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. BVAu-8 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BVAu-8
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.
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 |
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.
Equivalent designations
Standards and trade names that resolve to Precious Metal BVAu-8 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P00927
- Also called
- AWS BVAu-8
How much does BVAu-8 cost?
BVAu-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.
BVAu-8 — frequently asked
What is BVAu-8 used for?
BVAu-8 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?
BVAu-8 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 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 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?
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 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?
BVAu-8 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.
How much does BVAu-8 cost?
BVAu-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 A5.8M/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; 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.