Monel K-500 · UNS N05500 · W. Nr. 2.4375 · NiCu30Al · QQ-N-286
Monel K-500 (N05500): composition, properties, fittings and flanges
Monel K-500 (UNS N05500, W. Nr. 2.4375) adds 2.30-3.15 % aluminium and 0.35-0.85 % titanium to the Monel 400 nickel-copper base so the alloy can be precipitation hardened by fine gamma prime Ni3(Al,Ti) precipitates. After ageing it typically reaches 965 MPa (140 ksi) tensile strength and 690 MPa (100 ksi) yield strength with…
- UNS
- N05500
- W. Nr.
- 2.4375
- Density
- 8.44 g/cm³ (0.305 lb/in³)
- Key strength
- 965 MPa / 140 ksi
Identification and standards
| Short form | Monel K-500 · UNS N05500 · W. Nr. 2.4375 · NiCu30Al · QQ-N-286 |
|---|---|
| Classification | Age-hardenable nickel-copper-aluminium alloy |
| UNS | N05500 |
| Werkstoff number | 2.4375 |
| Material family | Monel Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Nickel + Cobalt (Ni+Co) | 63.0 min | Matrix |
| Copper (Cu) | 27.0 - 33.0 | Seawater resistance, hardening matrix |
| Aluminium (Al) | 2.30 - 3.15 | Gamma prime former - primary hardening element |
| Titanium (Ti) | 0.35 - 0.85 | Gamma prime former |
| Iron (Fe) | 2.00 max | - |
| Manganese (Mn) | 1.50 max | - |
| Silicon (Si) | 0.50 max | - |
| Carbon (C) | 0.18 max | - |
| Sulphur (S) | 0.010 max | - |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, aged, typical | 965 MPa / 140 ksi |
|---|---|
| 0.2 % yield strength, aged, typical | 690 MPa / 100 ksi |
| Elongation in 2 in, aged, typical | 20 % |
| Typical hardness, aged | 265 - 346 HB (approximately 27 - 35 HRC) |
| Typical hardness, annealed | 140 - 200 HB |
| Retains useful strength to | About 600 °C |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.44 g/cm³ (0.305 lb/in³) |
|---|---|
| Melting range | 1315 - 1350 °C (2400 - 2460 °F) |
| Modulus of elasticity | 179 GPa (26 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 17.5 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 13.7 µm/m·°C |
| Electrical resistivity at 20 °C | 0.61 µΩ·m |
| Magnetic permeability at -100 °C | Below 1.005, effectively non-magnetic |
Specifications by product form
| Bar / rod / wire / forgings | ASTM B865 / ASME SB-865, AMS 4676, QQ-N-286 |
|---|---|
| Plate / sheet / strip | ASTM B865 / QQ-N-286 |
| Seamless pipe & tube | ASTM B165 / B163 with age treatment by agreement |
| Forgings & flanges | ASTM B564 / ASME SB-564 (UNS N05500) |
| Butt weld fittings | ASTM B366 (WP500) or machined from bar / forging |
| Welding consumables | ERNiCu-7; age after welding to restore strength |
| UNS / EN / China | UNS N05500 · EN NiCu30Al · W. Nr. 2.4375 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged shafts, blocks and rings
- Fasteners and springs aged after forming
- Forged flanges to drawing
- Machined pump components, valve trim and bushings
- Non-sparking safety tools
Typical applications
- Propeller shafts, pump shafts, impeller shafts and rotor shafts in marine service
- Downhole drilling tools, MWD/LWD collars, stabilisers and non-magnetic drill collars
- Oil and gas valves, chokes, Christmas tree components and wellhead trim
- Marine fasteners, springs, chains, cable and screen wire
- Non-sparking tools for explosive atmospheres
- Doctor blades, scrapers, springs and bellows for the pulp and paper industry
Welding, forming and machining
- Heat treatment
- Solution anneal at 980-1040 °C then quench, followed by ageing at 595-610 °C for typically 8-16 hours and furnace cooling at 10-20 °C/h to about 480 °C. Cold working before ageing further increases strength.
- Welding
- Weld in the annealed condition with ERNiCu-7 filler, then age the assembly. Ageing welded structures recovers most of the strength, but prolonged exposure in the 650-870 °C range must be avoided.
- Machining
- Best machined in the annealed or hot-finished-and-aged condition. Fully aged K-500 requires carbide tooling and rigid setups; it is considerably stronger and tougher than Monel 400.
- Corrosion note
- K-500 can suffer stress corrosion cracking in aerated hydrofluoric acid vapour and on contact with mercury, so service-specific testing is recommended before specifying.
Buy Monel K-500 from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.