Nickel Alloy BNi-8 AS-BRAZED
Heat-treated state
UNS N99800 · ISO B-Ni8
Property set for the finished joint; use for design allowables on lap and honeycomb joints in stainless and Ni-base parents.
Values for the AS-BRAZED condition
What is BNi-8 AS-BRAZED?
BNi-8 AS-BRAZED is BNi-8 heat treated to AS-BRAZED — property set for the finished joint; use for design allowables on lap and honeycomb joints in stainless and Ni-base parents. BNi-8 AS-BRAZED has a tensile strength of 420 MPa (60.9 ksi), weaker than 97% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 180 GPa (26.1 Msi). BNi-8 AS-BRAZED has a density of 8.1 g/cm³ (0.293 lb/in³), lighter than 80% of nickel alloy grades. It melts at 980°C (1,796 °F).
Advantages
- Conducts heat well — 15 W/m·K (8.67 BTU/hr·ft·°F), better than 81% of nickel alloy grades
Limitations
- Limited ductility — 2%, worse than 95% of nickel alloy grades
- Needs corrosion protection — 40/100, worse than 95% of nickel alloy grades
- Difficult to weld — 10/100, worse than 94% of nickel alloy grades
- Low stiffness — 180 GPa (26.1 Msi), worse than 85% of nickel alloy grades
BNi-8 AS-BRAZED properties
Typical room-temperature values for BNi-8 AS-BRAZED; 6 are specific to this condition. Other listed values are BNi-8 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
BNi-8 AS-BRAZED has a density of 8.1 g/cm³ (0.293 lb/in³), lighter than 80% of nickel alloy grades. It melts at 980°C (1,796 °F).
Mechanical6
BNi-8 AS-BRAZED has a tensile strength of 420 MPa (60.9 ksi), weaker than 97% of nickel alloy grades. Elongation at break is 2% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal5
BNi-8 AS-BRAZED is rated for continuous service to 600°C (1,112 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), better than 81% of nickel alloy grades. Thermal expansion is 14.5 µm/m·K (8.06 µin/in·°F).
Electrical2
BNi-8 AS-BRAZED has an electrical resistivity of 1.1×10⁻⁶ Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (40/100), worse than 95% of nickel alloy grades.
Sustainability4
Producing a kilogram of BNi-8 AS-BRAZED takes about 150 MJ of energy and emits 12 kg of CO₂ — less than 68% of nickel alloy grades. Typical recycled content is 15%.
Manufacturability3
BNi-8 AS-BRAZED's machinability is poor (15/100, worse than 76% of nickel alloy grades); weldability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BNi-8 AS-BRAZED
Is BNi-8 easy to machine?
Solidified fillets are hard and brittle — remove excess by grinding or EDM rather than turning/milling.
Can BNi-8 be welded?
Not a structural weld filler; fusion welding over a BNi-8 joint remelts it and causes cracking, so keep weld heat away from brazed seams.
Can BNi-8 be formed, bent or molded?
Supplied only as powder, paste, tape or sintered preform; joint gap of 0.05–0.13 mm gives best capillary fill.
What surface finishes work on BNi-8?
Braze in vacuum with 0.1–1 mbar argon partial pressure to suppress Mn evaporation and furnace contamination; grit-blast and passivate stainless assemblies afterwards.
BNi-8 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 |
|---|---|---|
| Mn | 21.5 – 24.5 | 23 |
| Si | 6 – 8 | 7 |
| Cu | 4 – 5 | 4.5 |
| C | ≤ 0.1 | |
| Pintentionally P-free | ≤ 0.02 | |
| S | ≤ 0.02 | |
| Bintentionally B-free | ≤ 0.03 | |
| Al | ≤ 0.05 | |
| Ti | ≤ 0.05 | |
| Zr | ≤ 0.05 | |
| Other, total | ≤ 0.5 | |
| Ni | balance |
BNi-8 AS-BRAZED — frequently asked
What is BNi-8 AS-BRAZED used for?
BNi-8 AS-BRAZED is typically used for ductile nickel alloy joints, components requiring post-braze forming, boron-free joints for nuclear and neutron-sensitive parts, stainless steel brazed assemblies, thin-section heat exchanger joints and instrument and vacuum hardware. In short: boron and phosphorus free; most ductile nickel braze; needs argon partial pressure.
What is the tensile strength of BNi-8 AS-BRAZED?
BNi-8 AS-BRAZED has a typical tensile strength of 420 MPa (60.9 ksi) — weaker than 97% of nickel alloy grades.
Is BNi-8 AS-BRAZED easy to machine?
Not especially — machinability is rated poor (15/100, worse than 76% of nickel alloy grades). Solidified fillets are hard and brittle — remove excess by grinding or EDM rather than turning/milling.
Can BNi-8 AS-BRAZED be welded?
Not readily — weldability is rated not recommended (10/100). Not a structural weld filler; fusion welding over a BNi-8 joint remelts it and causes cracking, so keep weld heat away from brazed seams.
What surface finishes work on BNi-8 AS-BRAZED?
Braze in vacuum with 0.1–1 mbar argon partial pressure to suppress Mn evaporation and furnace contamination; grit-blast and passivate stainless assemblies afterwards.
Can BNi-8 AS-BRAZED be formed, bent or molded?
Supplied only as powder, paste, tape or sintered preform; joint gap of 0.05–0.13 mm gives best capillary fill.
What is the maximum service temperature of BNi-8 AS-BRAZED?
BNi-8 AS-BRAZED is rated for continuous use to about 600°C (1,112 °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)
- Nickel brazing filler metal product data (BNi series powders, pastes and tapes) — Wall Colmonoy / Lucas-Milhaupt (2023)
- GB/T 10859 (2008)
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.