Precious Metal BAu-3 AS-BRAZED
Heat-treated state
UNS P00350
Reference condition for design allowables of joints made with BAu-3 on stainless/Ni-base substrates.
Values for the AS-BRAZED condition
What is BAu-3 AS-BRAZED?
BAu-3 AS-BRAZED is BAu-3 heat treated to AS-BRAZED — reference condition for design allowables of joints made with BAu-3 on stainless/Ni-base substrates. BAu-3 AS-BRAZED has a tensile strength of 400 MPa (58 ksi), stronger than 55% of precious metal grades. Elongation at break is 20% and the elastic modulus is 105 GPa (15.2 Msi). BAu-3 AS-BRAZED has a density of 11 g/cm³ (0.397 lb/in³), heavier than 58% of precious metal grades. It melts at 975°C (1,787 °F).
Advantages
- High service temperature — 500°C (932 °F), better than 79% of precious metal grades
Limitations
- Poor heat conductor — 50 W/m·K (28.9 BTU/hr·ft·°F), worse than 79% of precious metal grades
- Limited formability — 70/100, worse than 78% of precious metal grades
- Limited ductility — 20%, worse than 77% of precious metal grades
- Low electrical conductivity — 11 % IACS, worse than 75% of precious metal grades
BAu-3 AS-BRAZED properties
Typical room-temperature values for BAu-3 AS-BRAZED; 2 are specific to this condition. Other listed values are BAu-3 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
BAu-3 AS-BRAZED has a density of 11 g/cm³ (0.397 lb/in³), heavier than 58% of precious metal grades. It melts at 975°C (1,787 °F).
Mechanical8
BAu-3 AS-BRAZED has a tensile strength of 400 MPa (58 ksi), stronger than 55% of precious metal grades. Elongation at break is 20% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
BAu-3 AS-BRAZED is rated for continuous service to 500°C (932 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), worse than 79% of precious metal grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
BAu-3 AS-BRAZED conducts electricity at 11 % IACS, worse than 75% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 53% of precious metal grades.
Sustainability4
Producing a kilogram of BAu-3 AS-BRAZED takes about 92,000 MJ of energy and emits 6,300 kg of CO₂ — more than 66% of precious metal grades. Typical recycled content is 60%.
Manufacturability4
BAu-3 AS-BRAZED's formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BAu-3 AS-BRAZED
Is BAu-3 easy to machine?
Filler alloy is not a structural machining stock; wire/foil is cut, sheared or stamped, and joints are cleaned by light grinding only to avoid smearing the soft noble metal.
Can BAu-3 be welded?
Not a weldable structural alloy — it is a brazing filler; braze in vacuum, dry hydrogen or inert gas at about 1000–1090 °C with tight 0.03–0.08 mm joint clearance.
Can BAu-3 be formed, bent or molded?
Very ductile FCC alloy: readily drawn to fine wire, rolled to foil and stamped into rings/washers, with interstage annealing after heavy reductions.
What surface finishes work on BAu-3?
Joints need no plating; degrease and pickle base metals before brazing, and avoid sulfur-bearing fluxes or cutting oils that stain the Cu/Ni-bearing fillet.
BAu-3 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 P00350 | 34.5 – 35.5 | 35 |
| Niimproves wetting, limits base-metal erosion | 2.5 – 3.5 | 3 |
| Other (total)total of all other elements per AWS A5.8 | ≤ 0.15 | |
| Cu | balance |
BAu-3 AS-BRAZED — frequently asked
What is BAu-3 AS-BRAZED used for?
BAu-3 AS-BRAZED is typically used for stainless steel and nickel-alloy brazing, electrical contact assemblies, instrument component joining and sensor housings. In short: best wetting on stainless; moderate melting range; silver-bearing, sulfur sensitive.
What is the tensile strength of BAu-3 AS-BRAZED?
BAu-3 AS-BRAZED has a typical tensile strength of 400 MPa (58 ksi) — stronger than 55% of precious metal grades.
Is BAu-3 AS-BRAZED easy to machine?
Filler alloy is not a structural machining stock; wire/foil is cut, sheared or stamped, and joints are cleaned by light grinding only to avoid smearing the soft noble metal.
Can BAu-3 AS-BRAZED be welded?
Not a weldable structural alloy — it is a brazing filler; braze in vacuum, dry hydrogen or inert gas at about 1000–1090 °C with tight 0.03–0.08 mm joint clearance.
What surface finishes work on BAu-3 AS-BRAZED?
Joints need no plating; degrease and pickle base metals before brazing, and avoid sulfur-bearing fluxes or cutting oils that stain the Cu/Ni-bearing fillet.
Can BAu-3 AS-BRAZED be formed, bent or molded?
Very ductile FCC alloy: readily drawn to fine wire, rolled to foil and stamped into rings/washers, with interstage annealing after heavy reductions.
What is the maximum service temperature of BAu-3 AS-BRAZED?
BAu-3 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 A5.8/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)
- Gold-based brazing filler metal datasheets (Au-Cu-Ni family) — precious-metal brazing alloy producers (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.