Nickel Alloy BNi-3 DIFF-BRAZED
Heat-treated state
UNS N99630 · ISO B-Ni3
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.
Values for the DIFF-BRAZED condition
Other BNi-3 tempers and conditions
BNi-3 is listed in 2 conditions; see the grade overview at BNi-3.
- DIFF-BRAZED
- AS-BRAZED
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
DIFF-BRAZEDThis page 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 |
What is BNi-3 DIFF-BRAZED?
BNi-3 DIFF-BRAZED is BNi-3 heat treated to DIFF-BRAZED — 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. BNi-3 DIFF-BRAZED has a tensile strength of 620 MPa (89.9 ksi), weaker than 68% of nickel alloy grades. Elongation at break is 4% and the elastic modulus is 205 GPa (29.7 Msi). BNi-3 DIFF-BRAZED 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).
Advantages
- Conducts heat well — 23 W/m·K (13.3 BTU/hr·ft·°F), better than 92% of nickel alloy grades
Limitations
- Needs corrosion protection — 40/100, worse than 95% of nickel alloy grades
- Limited ductility — 4%, worse than 93% of nickel alloy grades
- Difficult to weld — 20/100, worse than 84% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
BNi-3 DIFF-BRAZED properties
Typical room-temperature values for BNi-3 DIFF-BRAZED; 22 are specific to this condition. Other listed values are BNi-3 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
BNi-3 DIFF-BRAZED 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 DIFF-BRAZED has a tensile strength of 620 MPa (89.9 ksi), weaker than 68% of nickel alloy grades. Elongation at break is 4% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
BNi-3 DIFF-BRAZED is rated for continuous service to 900°C (1,652 °F). It conducts heat at 23 W/m·K (13.3 BTU/hr·ft·°F), better than 92% of nickel alloy grades. Thermal expansion is 12.6 µm/m·K (7 µin/in·°F).
Electrical2
BNi-3 DIFF-BRAZED has an electrical resistivity of 9.5×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 95% of nickel alloy grades.
Sustainability3
Producing a kilogram of BNi-3 DIFF-BRAZED 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 DIFF-BRAZED's machinability is poor (15/100, worse than 76% of nickel alloy grades); weldability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BNi-3 DIFF-BRAZED
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.
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.
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 | — |
BNi-3 DIFF-BRAZED — frequently asked
What is BNi-3 DIFF-BRAZED used for?
BNi-3 DIFF-BRAZED 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 DIFF-BRAZED?
BNi-3 DIFF-BRAZED has a typical tensile strength of 620 MPa (89.9 ksi) — weaker than 68% of nickel alloy grades. Strength varies by condition: see the 2 listed tempers.
Is BNi-3 DIFF-BRAZED easy to machine?
Not especially — machinability is rated poor (15/100, worse than 76% 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 DIFF-BRAZED be welded?
Not readily — weldability is rated poor (20/100). 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 DIFF-BRAZED?
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 DIFF-BRAZED 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 DIFF-BRAZED?
BNi-3 DIFF-BRAZED is rated for continuous use to about 900°C (1,652 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.