Nickel Alloy BNi-4 AS-BRAZED
Heat-treated state
UNS N99640 · ISO B-Ni4
Design condition for joint strength after a 1010–1175 °C vacuum or dry-hydrogen braze cycle.
Values for the AS-BRAZED condition
Other BNi-4 tempers and conditions
BNi-4 is listed in 2 conditions; see the grade overview at BNi-4.
- DIFF-BRAZED
- AS-BRAZED
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Diffusion-brazed / post-braze diffusion heat treated joint | Long hold above the braze temperature dissolves boride centre-line, raising joint remelt temperature and ductility. | 350 | 560 | 6 | 25 HRC | 1.9 % IACS |
AS-BRAZEDThis page As-brazed joint (deposited filler metal) | Design condition for joint strength after a 1010–1175 °C vacuum or dry-hydrogen braze cycle. | 400 | 450 | 2 | 33 HRC | 1.6 % IACS |
What is BNi-4 AS-BRAZED?
BNi-4 AS-BRAZED is BNi-4 heat treated to AS-BRAZED — design condition for joint strength after a 1010–1175 °C vacuum or dry-hydrogen braze cycle. BNi-4 AS-BRAZED has a tensile strength of 450 MPa (65.3 ksi), weaker than 94% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 190 GPa (27.6 Msi). BNi-4 AS-BRAZED has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 980°C (1,796 °F).
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
- Needs corrosion protection — 42/100, worse than 94% of nickel alloy grades
- Difficult to weld — 15/100, worse than 87% of nickel alloy grades
BNi-4 AS-BRAZED properties
Typical room-temperature values for BNi-4 AS-BRAZED; 22 are specific to this condition. Other listed values are BNi-4 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
BNi-4 AS-BRAZED has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 980°C (1,796 °F).
Mechanical8
BNi-4 AS-BRAZED has a tensile strength of 450 MPa (65.3 ksi), weaker than 94% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 190 GPa (27.6 Msi).
Thermal6
BNi-4 AS-BRAZED is rated for continuous service to 900°C (1,652 °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 13.5 µm/m·K (7.5 µin/in·°F).
Electrical2
BNi-4 AS-BRAZED has an electrical resistivity of 1.1×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 94% of nickel alloy grades.
Sustainability4
Producing a kilogram of BNi-4 AS-BRAZED takes about 185 MJ of energy and emits 14 kg of CO₂ — more than 73% of nickel alloy grades. Typical recycled content is 15%.
Manufacturability5
BNi-4 AS-BRAZED's machinability is not recommended (12/100, worse than 86% of nickel alloy grades); weldability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BNi-4 AS-BRAZED
Is BNi-4 easy to machine?
Solidified filler is hard and boride-bearing — remove excess fillets by grinding or EDM rather than turning; keep joint clean-up to a minimum.
Can BNi-4 be welded?
Not a fusion-welding filler; braze in vacuum (10⁻⁴ mbar range) or dry hydrogen at 1010–1175 °C with joint clearances of about 0.025–0.10 mm.
Can BNi-4 be formed, bent or molded?
Supplied as powder, paste, tape or rapidly-solidified ribbon; only the amorphous ribbon can be cut and formed into preforms.
What surface finishes work on BNi-4?
Chromium-free deposit oxidises above ~900 °C — apply aluminide or Cr-rich coatings, or passivate the parent stainless after brazing, for aggressive service.
BNi-4 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 | 3 – 4 | 3.5 |
| B | 1.5 – 2.2 | 1.8 |
| Fe | ≤ 1.5 | 0.5 |
| C | ≤ 0.06 | 0.03 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Al | ≤ 0.05 | — |
| Ti | ≤ 0.05 | — |
| Zr | ≤ 0.05 | — |
| Other elements, total | ≤ 0.5 | — |
| Ni | balance | — |
BNi-4 AS-BRAZED — frequently asked
What is BNi-4 AS-BRAZED used for?
BNi-4 AS-BRAZED is typically used for ductile joint brazing, stainless steel assemblies and food and medical equipment brazing. In short: lower boron than BNi-3; more ductile brazed joints; chromium-free deposit.
What is the tensile strength of BNi-4 AS-BRAZED?
BNi-4 AS-BRAZED has a typical tensile strength of 450 MPa (65.3 ksi) — weaker than 94% of nickel alloy grades. Strength varies by condition: see the 2 listed tempers.
Is BNi-4 AS-BRAZED easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 86% of nickel alloy grades). Solidified filler is hard and boride-bearing — remove excess fillets by grinding or EDM rather than turning; keep joint clean-up to a minimum.
Can BNi-4 AS-BRAZED be welded?
Not readily — weldability is rated poor (15/100). Not a fusion-welding filler; braze in vacuum (10⁻⁴ mbar range) or dry hydrogen at 1010–1175 °C with joint clearances of about 0.025–0.10 mm.
What surface finishes work on BNi-4 AS-BRAZED?
Chromium-free deposit oxidises above ~900 °C — apply aluminide or Cr-rich coatings, or passivate the parent stainless after brazing, for aggressive service.
Can BNi-4 AS-BRAZED be formed, bent or molded?
Supplied as powder, paste, tape or rapidly-solidified ribbon; only the amorphous ribbon can be cut and formed into preforms.
What is the maximum service temperature of BNi-4 AS-BRAZED?
BNi-4 AS-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 A5.8/A5.8M Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (Nickel brazing filler metals) — ASM International (1993)
- AWS Brazing Handbook, 5th ed. — American Welding Society (2007)
- Nickel braze filler metal powder/paste/foil datasheets (Ni-Si-B family) — Various braze 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.