Nickel Alloy BNi-5a AS-BRAZED
Heat-treated state
UNS N99651 · ISO B-Ni5a
Baseline condition straight out of the vacuum furnace; hardest and most brittle because of retained centreline borides.
Values for the AS-BRAZED condition
Other BNi-5a tempers and conditions
BNi-5a is listed in 2 conditions; see the grade overview at BNi-5a.
- AS-BRAZED
- DIFF
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AS-BRAZEDThis page no post-braze diffusion cycle | Baseline condition straight out of the vacuum furnace; hardest and most brittle because of retained centreline borides. | 420 | 480 | 1 | 55 HRC | 1.3 % IACS |
Diffusion heat treated after brazing | Select where joint ductility, higher remelt temperature and creep life matter; boron diffuses into the parent metal and the brittle centreline is largely eliminated. | 430 | 650 | 5 | 36 HRC | 1.6 % IACS |
What is BNi-5a AS-BRAZED?
BNi-5a AS-BRAZED is BNi-5a heat treated to AS-BRAZED — baseline condition straight out of the vacuum furnace; hardest and most brittle because of retained centreline borides. The elastic modulus is 205 GPa (29.7 Msi). BNi-5a AS-BRAZED has a density of 7.85 g/cm³ (0.284 lb/in³), lighter than 95% of nickel alloy grades. It melts at 1,030°C (1,886 °F).
Limitations
- Difficult to machine — 3/100, worse than 100% of nickel alloy grades
- Difficult to weld — 5/100, worse than 99% of nickel alloy grades
- Needs corrosion protection — 66/100, worse than 84% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
BNi-5a AS-BRAZED properties
Typical room-temperature values for BNi-5a AS-BRAZED; 21 are specific to this condition. Other listed values are BNi-5a reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
BNi-5a AS-BRAZED has a density of 7.85 g/cm³ (0.284 lb/in³), lighter than 95% of nickel alloy grades. It melts at 1,030°C (1,886 °F).
Mechanical6
The elastic modulus is 205 GPa (29.7 Msi).
Thermal6
BNi-5a AS-BRAZED is rated for continuous service to 900°C (1,652 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), better than 65% of nickel alloy grades. Thermal expansion is 13 µm/m·K (7.22 µin/in·°F).
Electrical3
BNi-5a AS-BRAZED conducts electricity at 1.3 % IACS, worse than 89% of nickel alloy grades.
Chemical & Environmental2
Corrosion resistance is good (66/100), worse than 84% of nickel alloy grades.
Sustainability3
Producing a kilogram of BNi-5a AS-BRAZED takes about 200 MJ of energy and emits 14 kg of CO₂ — more than 78% of nickel alloy grades. Typical recycled content is 10%.
Manufacturability5
BNi-5a AS-BRAZED's machinability is not recommended (3/100, worse than 100% of nickel alloy grades); weldability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BNi-5a AS-BRAZED
Is BNi-5a easy to machine?
The solidified braze deposit is a hard boride/silicide-bearing alloy — remove only by grinding or EDM, never expect conventional turning or milling.
Can BNi-5a be welded?
Not a welding consumable; fusion welding over a BNi-5a joint causes hot cracking and boride liquation, so re-braze rather than weld repair.
Can BNi-5a be formed, bent or molded?
Supplied as atomized powder, binder paste, tape or sintered preform — no wrought forming; control joint gap to 0.025–0.075 mm for capillary flow.
What surface finishes work on BNi-5a?
Braze in vacuum (10⁻⁴ mbar) or dry hydrogen at about 1120–1205 °C, hold briefly, then apply a diffusion cycle; fillets can be blended and passivated with the parent stainless steel.
BNi-5a 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 | 18.5 – 19.5 | 19 |
| Si | 7 – 7.5 | 7.25 |
| Bmelting-point depressant, diffuses into parent metal | 1 – 1.3 | 1.15 |
| C | ≤ 0.06 | — |
| Fe | ≤ 0.5 | — |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Al | ≤ 0.05 | — |
| Ti | ≤ 0.05 | — |
| Zr | ≤ 0.05 | — |
| Other (total) | ≤ 0.5 | — |
| Ni | balance | — |
BNi-5a AS-BRAZED — frequently asked
What is BNi-5a AS-BRAZED used for?
BNi-5a AS-BRAZED is typically used for turbine hardware brazing, high-temperature nickel alloy assemblies, tight-clearance capillary joints, stainless steel vacuum-brazed assemblies, hot-section static components and heat exchanger and manifold joints. In short: improved flow versus BNi-5; high-chromium oxidation resistance; 950 C service limit.
Is BNi-5a AS-BRAZED easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 100% of nickel alloy grades). The solidified braze deposit is a hard boride/silicide-bearing alloy — remove only by grinding or EDM, never expect conventional turning or milling.
Can BNi-5a AS-BRAZED be welded?
Not readily — weldability is rated not recommended (5/100). Not a welding consumable; fusion welding over a BNi-5a joint causes hot cracking and boride liquation, so re-braze rather than weld repair.
What surface finishes work on BNi-5a AS-BRAZED?
Braze in vacuum (10⁻⁴ mbar) or dry hydrogen at about 1120–1205 °C, hold briefly, then apply a diffusion cycle; fillets can be blended and passivated with the parent stainless steel.
Can BNi-5a AS-BRAZED be formed, bent or molded?
Supplied as atomized powder, binder paste, tape or sintered preform — no wrought forming; control joint gap to 0.025–0.075 mm for capillary flow.
What is the maximum service temperature of BNi-5a AS-BRAZED?
BNi-5a 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 A5.8M/A5.8 Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- Brazing Handbook, 5th ed. — American Welding Society (2007)
- Nickel-base brazing filler metal powder datasheets — Wall Colmonoy / Höganäs / Lucas-Milhaupt (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.