Nickel Alloy BNi-3
UNS N99630 · ISO B-Ni3
BNi-3 (UNS N99630) is a chromium-free Ni-Si-B brazing filler with a density of 8.2 g/cm³, supplied as powder, paste, sintered preform or rapidly solidified amorphous foil.
Reference datasheet — BNi-3 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.
BNi-3 tempers and conditions
BNi-3 is supplied in 2 conditions, soft to hard.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Diffusion-brazed / post-braze diffusion cycle | Select when a long hold above/near solidus is used to diffuse B and Si out of the joint, raising joint remelt temperature and ductility. | 400 | 620 | 4 | 35 HRC | 1.8 % IACS |
filler after furnace cycle (no post-braze heat treat) | Property set to quote for finished narrow-gap joints on austenitic stainless / Ni-base base metals. | 500 | 550 | 1 | 53 HRC | 1.6 % IACS |
Supply forms, finishes and certifications
Ways BNi-3 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOIL | Amorphous foil / ribbon | Supply form |
PREFORM | Sintered preform | Supply form |
PASTE | Powder pre-mixed with organic binder/gel | Printing process |
POWDERDefault | Gas-atomised braze powder | Printing process |
What is BNi-3?
BNi-3 (UNS N99630) is a chromium-free Ni-Si-B brazing filler with a density of 8.2 g/cm³, supplied as powder, paste, sintered preform or rapidly solidified amorphous foil. Its high fluidity suits close-fit joints of 0.02–0.08 mm brazed in vacuum or dry hydrogen at 1010–1177 °C, and the absence of chromium avoids chromium carbide formation at the joint. The deposit is a hard, brittle nickel boride/silicide composite with a machinability score of 8, so cleanup is by grinding or EDM. Fillet corrosion resistance is lower than chromium-bearing BNi-2, the usual alternative for wet or oxidising service. BNi-3 has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 982°C (1,800 °F). BNi-3 has a tensile strength of 480 MPa (69.6 ksi), weaker than 89% of nickel alloy grades. Elongation at break is 1% and the elastic modulus is 200 GPa (29 Msi).
What is BNi-3 used for?
- thin-gap furnace brazing
- nickel alloy joints
- aerospace tubing brazes
Advantages
- Conducts heat well — 20 W/m·K (11.6 BTU/hr·ft·°F), better than 87% of nickel alloy grades
Limitations
- Limited ductility — 1%, worse than 98% of nickel alloy grades
- Needs corrosion protection — 35/100, worse than 96% of nickel alloy grades
- Difficult to machine — 8/100, worse than 96% of nickel alloy grades
- Difficult to weld — 10/100, worse than 94% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
BNi-3 properties
Typical room-temperature values; bars are the position among nickel alloy grades.
Physical3
BNi-3 has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 982°C (1,800 °F).
Mechanical7
BNi-3 has a tensile strength of 480 MPa (69.6 ksi), weaker than 89% of nickel alloy grades. Elongation at break is 1% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
BNi-3 is rated for continuous service to 760°C (1,400 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), better than 87% of nickel alloy grades. Thermal expansion is 12.6 µm/m·K (7 µin/in·°F).
Electrical2
BNi-3 has an electrical resistivity of 1.1×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 96% of nickel alloy grades.
Sustainability3
Producing a kilogram of BNi-3 takes about 165 MJ of energy and emits 13.5 kg of CO₂ — more than 54% of nickel alloy grades. Typical recycled content is 10%.
Manufacturability5
BNi-3's machinability is not recommended (8/100, worse than 96% of nickel alloy grades); weldability not recommended (10/100).
Common Calculations4
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 nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. BNi-3 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BNi-3
Is BNi-3 easy to machine?
Solidified deposit is a hard brittle Ni-boride/silicide composite — remove by grinding or EDM only; avoid single-point cutting.
Can BNi-3 be welded?
Not a welding consumable; remelting or fusion welding over a BNi-3 joint causes boron-induced hot cracking and liquation of the base metal.
Can BNi-3 be formed, bent or molded?
Supplied as powder, paste, sintered preform or rapidly solidified amorphous foil; only the foil can be sheared, punched and wrapped to shape.
BNi-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 |
|---|---|---|
| Si | 4 – 5 | 4.5 |
| B | 2.75 – 3.5 | 3.1 |
| Fe | ≤ 0.5 | 0.2 |
| C | ≤ 0.06 | 0.03 |
| P | ≤ 0.02 | |
| S | ≤ 0.02 | |
| Al | ≤ 0.05 | |
| Ti | ≤ 0.05 | |
| Zr | ≤ 0.05 | |
| Other elements, totalAWS A5.8 residuals limit | ≤ 0.5 | |
| Ni | balance |
What surface finishes work on BNi-3?
Vacuum or dry hydrogen furnace cycle at 1010–1177 °C with joint gaps 0.02–0.08 mm; no flux needed in protective atmosphere, and Cr-free chemistry keeps base-metal carbide formation low but the fillet should be kept out of wet corrosive service or plated/coated.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Nickel Alloy BNi-3 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N99630
- ISO
- B-Ni3
How much does BNi-3 cost?
BNi-3 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
BNi-3 — frequently asked
What is BNi-3 used for?
BNi-3 is typically used for thin-gap furnace brazing, nickel alloy joints and aerospace tubing brazes. In short: chromium-free nickel braze; best for tight gaps; avoids chromium carbide formation.
What is the tensile strength of BNi-3?
BNi-3 has a typical tensile strength of 480 MPa (69.6 ksi) — weaker than 89% of nickel alloy grades. Strength varies by condition: see the 2 listed tempers.
Is BNi-3 easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 96% of nickel alloy grades). Solidified deposit is a hard brittle Ni-boride/silicide composite — remove by grinding or EDM only; avoid single-point cutting.
Can BNi-3 be welded?
Not readily — weldability is rated not recommended (10/100). Not a welding consumable; remelting or fusion welding over a BNi-3 joint causes boron-induced hot cracking and liquation of the base metal.
What surface finishes work on BNi-3?
Vacuum or dry hydrogen furnace cycle at 1010–1177 °C with joint gaps 0.02–0.08 mm; no flux needed in protective atmosphere, and Cr-free chemistry keeps base-metal carbide formation low but the fillet should be kept out of wet corrosive service or plated/coated.
Can BNi-3 be formed, bent or molded?
Supplied as powder, paste, sintered preform or rapidly solidified amorphous foil; only the foil can be sheared, punched and wrapped to shape.
What is the maximum service temperature of BNi-3?
BNi-3 is rated for continuous use to about 760°C (1,400 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BNi-3 cost?
BNi-3 is a high-cost nickel alloy ($$$$), 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)
- Brazing Handbook, 5th ed. — American Welding Society (2007)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- Nicrobraz / BNi-3 braze alloy data — Wall Colmonoy (2022)
- MBF-30 amorphous brazing foil datasheet — Metglas / Hitachi Metals (2021)
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.