Nickel Alloy BNi-2
UNS N99620 · ASTM A5.8 BNi-2 · ISO B-Ni2 · also Nicrobraz 30
BNi-2 is the most widely used nickel brazing filler (UNS N99620, AWS A5.8 BNi-2, also sold as Nicrobraz 30), a Ni-Cr-Fe-Si-B alloy with a melting point of 971 °C and a density of 7.9 g/cm³.
Reference datasheet — BNi-2 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-2 tempers and conditions
BNi-2 is supplied in one standard condition, AS-BRAZED.
Supply forms, finishes and certifications
Ways BNi-2 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-ROD | Cast rod / stick | Supply form |
FOIL-AM | Amorphous foil | Supply form |
PREFORM | Sintered preform | Supply form |
PASTE | Powder pre-mixed with organic/neutral binder for dispensing | Printing process |
POWDERDefault | Gas-atomised braze powder | Printing process |
TAPE | Transfer tape / sheet | Printing process |
What is BNi-2?
BNi-2 is the most widely used nickel brazing filler (UNS N99620, AWS A5.8 BNi-2, also sold as Nicrobraz 30), a Ni-Cr-Fe-Si-B alloy with a melting point of 971 °C and a density of 7.9 g/cm³. It flows freely and fills gaps well, making it the default choice for stainless steel and nickel alloy assemblies brazed in vacuum, dry hydrogen or argon at 1010–1177 °C with 0.025–0.075 mm joint gaps. Supply forms include powder, paste, tape, sintered preform, cast rod and amorphous foil. The solidified fillet is brittle and unmachinable, and boron can erode thin sections; use BNi-3 where chromium must be excluded. BNi-2 has a density of 7.9 g/cm³ (0.285 lb/in³), lighter than 92% of nickel alloy grades. It melts at 971°C (1,780 °F). BNi-2 has a tensile strength of 690 MPa (100 ksi), weaker than 57% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi).
What is BNi-2 used for?
- stainless steel honeycomb seals
- heat exchanger brazing
- jet engine components
- general vacuum furnace brazing
Advantages
- Conducts heat well — 30 W/m·K (17.3 BTU/hr·ft·°F), better than 93% of nickel alloy grades
Limitations
- Limited ductility — 2%, worse than 95% of nickel alloy grades
- Hard to polish — 55/100, worse than 95% of nickel alloy grades
- Difficult to machine — 10/100, worse than 93% of nickel alloy grades
- Limited formability — 5/100, worse than 91% of nickel alloy grades
- Needs corrosion protection — 62/100, worse than 87% of nickel alloy grades
BNi-2 properties
Typical room-temperature values; bars are the position among nickel alloy grades.
Physical3
BNi-2 has a density of 7.9 g/cm³ (0.285 lb/in³), lighter than 92% of nickel alloy grades. It melts at 971°C (1,780 °F).
Mechanical7
BNi-2 has a tensile strength of 690 MPa (100 ksi), weaker than 57% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
BNi-2 is rated for continuous service to 870°C (1,598 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), better than 93% of nickel alloy grades. Thermal expansion is 12.8 µm/m·K (7.11 µin/in·°F).
Electrical1
Chemical & Environmental2
Corrosion resistance is good (62/100), worse than 87% of nickel alloy grades.
Sustainability4
Producing a kilogram of BNi-2 takes about 170 MJ of energy and emits 13 kg of CO₂ — more than 61% of nickel alloy grades. Typical recycled content is 15%.
Manufacturability6
BNi-2's machinability is not recommended (10/100, worse than 93% of nickel alloy grades); weldability poor (15/100); formability not recommended (5/100).
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-2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BNi-2
Is BNi-2 easy to machine?
Solidified BNi-2 is boride-hardened and effectively unmachinable — remove excess fillets by grinding or diamond wheel, and design for minimal cleanup.
Can BNi-2 be welded?
Not a welding consumable; avoid fusion welding over a BNi-2 joint since remelted boride eutectic cracks readily.
Can BNi-2 be formed, bent or molded?
Supplied as powder, paste, tape, sintered preform or rapidly solidified amorphous foil — only the foil can be stamped or wrapped; cast bar is brittle.
BNi-2 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 |
|---|---|---|
| Cr | 6 – 8 | 7 |
| Si | 4 – 5 | 4.5 |
| Bmelting-point depressant; causes base-metal erosion/boride formation | 2.75 – 3.5 | 3.1 |
| Fe | 2.5 – 3.5 | 3 |
| C | ≤ 0.06 | 0.03 |
| P | ≤ 0.02 | |
| S | ≤ 0.02 | |
| Al | ≤ 0.05 | |
| Ti | ≤ 0.05 | |
| Zr | ≤ 0.05 | |
| Co | ≤ 0.1 | |
| Se | ≤ 0.01 | |
| Other, totalsum of unspecified residuals | ≤ 0.5 | |
| Ni≈79 % nominal | balance |
What surface finishes work on BNi-2?
Braze in vacuum, dry hydrogen or argon at 1010–1177 °C with 0.025–0.075 mm gaps; passivate or electropolish the assembly afterwards, and do not plate over exposed braze fillets without masking.
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-2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N99620
- ASTM
- A5.8 BNi-2
- ISO
- B-Ni2
- Trade names
- Nicrobraz 30
How much does BNi-2 cost?
BNi-2 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
BNi-2 — frequently asked
What is BNi-2 used for?
BNi-2 is typically used for stainless steel honeycomb seals, heat exchanger brazing, jet engine components and general vacuum furnace brazing. In short: most widely used nickel braze; strong gap-filling and flow; melts at 971 °C.
What is the tensile strength of BNi-2?
BNi-2 has a typical tensile strength of 690 MPa (100 ksi) — weaker than 57% of nickel alloy grades.
Is BNi-2 easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 93% of nickel alloy grades). Solidified BNi-2 is boride-hardened and effectively unmachinable — remove excess fillets by grinding or diamond wheel, and design for minimal cleanup.
Can BNi-2 be welded?
Not readily — weldability is rated poor (15/100). Not a welding consumable; avoid fusion welding over a BNi-2 joint since remelted boride eutectic cracks readily.
What surface finishes work on BNi-2?
Braze in vacuum, dry hydrogen or argon at 1010–1177 °C with 0.025–0.075 mm gaps; passivate or electropolish the assembly afterwards, and do not plate over exposed braze fillets without masking.
Can BNi-2 be formed, bent or molded?
Supplied as powder, paste, tape, sintered preform or rapidly solidified amorphous foil — only the foil can be stamped or wrapped; cast bar is brittle.
What is the maximum service temperature of BNi-2?
BNi-2 is rated for continuous use to about 870°C (1,598 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BNi-2 cost?
BNi-2 is a high-cost nickel alloy ($$$$), 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)
- ASM Handbook Vol. 6 — Welding, Brazing, and Soldering (nickel braze filler metals) — ASM International (1993)
- Brazing Handbook, 5th ed. — American Welding Society (2007)
- Nickel braze filler metal datasheets (BNi-2 / Nicrobraz 30 class, powder, paste, tape, amorphous foil) — Wall Colmonoy / Lucas-Milhaupt / Metglas (2023)
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.