Precious Metal BVAg-6b
UNS P07507
BVAg-6b is the vacuum-service version of the BAg-6 silver-copper-zinc braze filler (nominally 50Ag-Cu-Zn, UNS P07507), refined to low-vapor-pressure impurity limits so zinc outgassing stays low enough for vacuum furnace use.
Reference datasheet — BVAg-6b 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-6b tempers and conditions
BVAg-6b is supplied in one standard condition, AS-BRAZED.
Supply forms, finishes and certifications
Ways BVAg-6b is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
PREFORM | Stamped rings, washers, discs | Supply form |
STRIP | Strip / foil | Supply form |
WIREDefault | Wire / rod | Supply form |
WIRE-HD | Wire | Supply form |
PASTE | Powder in clean-burnout organic binder | Printing process |
POWDER | Atomised, screened for paste/tape | Printing process |
What is BVAg-6b?
BVAg-6b is the vacuum-service version of the BAg-6 silver-copper-zinc braze filler (nominally 50Ag-Cu-Zn, UNS P07507), refined to low-vapor-pressure impurity limits so zinc outgassing stays low enough for vacuum furnace use. It is chosen for stainless steel and copper alloy vacuum joints where a 50% silver filler gives a wide melting range and good gap filling, and is stocked as annealed and hard-drawn wire, strip, preforms, powder and paste. As-brazed deposits run about 340 MPa tensile with 150 MPa yield and 25% elongation. Residual zinc still restricts it in electron-tube and ultra-high-vacuum work; use zinc-free BVAg-8 or BVAg-18 for those assemblies. BVAg-6b has a density of 9.6 g/cm³ (0.347 lb/in³), lighter than 80% of precious metal grades. It melts at 779°C (1,434 °F). BVAg-6b has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 68% of precious metal grades. Elongation at break is 25% and the elastic modulus is 100 GPa (14.5 Msi).
What is BVAg-6b used for?
- Vacuum furnace brazing of stainless steel assemblies
- Copper alloy vacuum joints
- Stainless-to-copper tube and fitting transitions
- Ring and washer preforms for tube joints
- Vacuum chamber fittings and flange subassemblies
- Torch-brazed copper alloy plumbing in air with white flux
Advantages
- Low embodied carbon — 57 kg CO₂/kg, better than 83% of precious metal grades
Limitations
- Needs corrosion protection — 55/100, worse than 94% of precious metal grades
- Difficult to weld — 20/100, worse than 86% of precious metal grades
BVAg-6b properties
Typical room-temperature values; bars are the position among precious metal grades.
Physical3
BVAg-6b has a density of 9.6 g/cm³ (0.347 lb/in³), lighter than 80% of precious metal grades. It melts at 779°C (1,434 °F).
Mechanical10
BVAg-6b has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 68% of precious metal grades. Elongation at break is 25% and the elastic modulus is 100 GPa (14.5 Msi).
Thermal6
BVAg-6b is rated for continuous service to 370°C (698 °F). It conducts heat at 220 W/m·K (127.1 BTU/hr·ft·°F), better than 72% of precious metal grades. Thermal expansion is 18.2 µm/m·K (10.1 µin/in·°F).
Electrical3
BVAg-6b conducts electricity at 48 % IACS, better than 70% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 94% of precious metal grades.
Sustainability4
Producing a kilogram of BVAg-6b takes about 800 MJ of energy and emits 57 kg of CO₂ — less than 83% of precious metal grades. Typical recycled content is 60%.
Manufacturability6
BVAg-6b's machinability is fair (35/100, worse than 73% of precious metal grades); weldability poor (20/100); formability very good (80/100).
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-6b is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BVAg-6b
Is BVAg-6b easy to machine?
Rarely machined; the alloy is soft and gummy — use sharp, high-rake tools, generous lubricant and take scrap back to the refiner.
Can BVAg-6b be welded?
Not a base metal for fusion welding; it is the filler — braze at 850–900 °C in vacuum (10⁻⁴ mbar or better) or dry hydrogen, or with a torch and white flux in air.
Can BVAg-6b be formed, bent or molded?
Excellent cold formability when annealed — drawn to fine wire, rolled to foil and stamped into rings; interanneal around 600–650 °C in a protective atmosphere.
BVAg-6b 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 |
|---|---|---|
| Ag | 49 – 51 | 50 |
| Znrestricted for low vapour pressure | ≤ 0 | |
| Cdrestricted for low vapour pressure | ≤ 0 | |
| P | ≤ 0 | |
| Pb | ≤ 0 | |
| other elements totalAWS A5.8 vacuum-grade impurity limit | ≤ 0.15 | |
| Cu | ≥ 48.5 (balance) |
What surface finishes work on BVAg-6b?
Fillets can be bright-dipped or polished to a silver finish; passivate or lacquer if sulphur tarnishing of exposed joints is a concern, and avoid nitric-acid pickles that dissolve the filler.
Equivalent designations
Standards and trade names that resolve to Precious Metal BVAg-6b in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P07507
- Also called
- BAg-6
How much does BVAg-6b cost?
BVAg-6b 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-6b — frequently asked
What is BVAg-6b used for?
BVAg-6b is typically used for vacuum furnace brazing of stainless steel assemblies, copper alloy vacuum joints, stainless-to-copper tube and fitting transitions, ring and washer preforms for tube joints, vacuum chamber fittings and flange subassemblies and torch-brazed copper alloy plumbing in air with white flux. In short: vacuum-grade 50Ag filler; controlled zinc outgassing; wide-gap brazing filler.
What is the yield strength of BVAg-6b?
BVAg-6b has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 340 MPa (49.3 ksi) — weaker than 68% of precious metal grades.
Is BVAg-6b easy to machine?
Not especially — machinability is rated fair (35/100, worse than 73% of precious metal grades). Rarely machined; the alloy is soft and gummy — use sharp, high-rake tools, generous lubricant and take scrap back to the refiner.
Can BVAg-6b be welded?
Not readily — weldability is rated poor (20/100). Not a base metal for fusion welding; it is the filler — braze at 850–900 °C in vacuum (10⁻⁴ mbar or better) or dry hydrogen, or with a torch and white flux in air.
What surface finishes work on BVAg-6b?
Fillets can be bright-dipped or polished to a silver finish; passivate or lacquer if sulphur tarnishing of exposed joints is a concern, and avoid nitric-acid pickles that dissolve the filler.
Can BVAg-6b be formed, bent or molded?
Excellent cold formability when annealed — drawn to fine wire, rolled to foil and stamped into rings; interanneal around 600–650 °C in a protective atmosphere.
What is the maximum service temperature of BVAg-6b?
BVAg-6b 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-6b cost?
BVAg-6b 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 (vacuum-grade BVAg classifications) — American Welding Society (2019)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (silver brazing filler metals) — ASM International (1993)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Ag, Cu, Ag-Cu system) — ASM International (1990)
- Vacuum-grade silver brazing alloy data (Ag-Cu 50/50) — Lucas-Milhaupt / Morgan Advanced Materials (Wesgo Metals) (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.