Alloy K-500
Also known as Monel® K-500, UNS N05500, Werkstoff 2.4375
Alloy K-500 is an age-hardened nickel-copper alloy combining very high strength with excellent seawater corrosion resistance.
Alloy K-500 (UNS N05500) is a precipitation-hardenable Nickel-Copper alloy refined by Electro Slag Refining (ESR), offering a unique combination of very high strength and hardness with excellent corrosion resistance in a wide range of environments including seawater, hydrofluoric acid, sulphuric acid, alkalis and chlorides.
With low magnetic permeability to very low temperatures (Curie temperature -90°C), high fatigue strength in seawater and listed in NACE MR0175 for sour oil and gas service, it is a primary choice for highly loaded downhole and marine components. Predominantly supplied in the Hot Worked and Precipitation Treated condition to the most demanding material specifications.
We stock bar in the UK and USA. Plate, tube and fittings are available on enquiry; forgings and castings to order.
- High strength and hardness from sub-zero to elevated temperatures
- Excellent corrosion resistance in a wide range of environments
- Resistant to chloride stress corrosion
- Good resistance to impingement attack
- High fatigue strength in seawater
- Low magnetic permeability to very low temperatures
| Element | Min | Max |
|---|---|---|
| Nickel (Ni) | 63.00 | - |
| Copper (Cu) | 27.0 | 33.0 |
| Aluminium (Al) | 2.30 | 3.15 |
| Titanium (Ti) | 0.35 | 0.85 |
| Iron (Fe) | - | 2.0 |
| Manganese (Mn) | - | 1.50 |
| Silicon (Si) | - | 0.50 |
| Carbon (C) | - | 0.25 |
| Sulphur (S) | - | 0.010 |
| Property | Imperial | Metric |
|---|---|---|
| 0.2% Proof stress (min) | 105 ksi | 724 N/mm² |
| Tensile strength (min) | 140 ksi | 965 N/mm² |
| Elongation (5.65√S0 & 4D) | 20% | |
| Hardness (Rockwell C) | 27-35 | |
| Impact strength (≤ -29°C) | 27 J av (20 J min) |
| Property | Imperial | Metric |
|---|---|---|
| 0.2% Proof stress (min) | 105 ksi | 724 N/mm² |
| Tensile strength (min) | 140 ksi | 965 N/mm² |
| Elongation (5.65√S0 & 4D) | 20% | |
| Hardness (Rockwell C) | 27-35 | |
| Impact strength (≤ -29°C) | 27 J av (20 J min) |
| Property | Imperial | Metric |
|---|---|---|
| 0.2% Proof stress (min) | 110 ksi | 760 N/mm² |
| Tensile strength (min) | 145 ksi | 1000 N/mm² |
| Elongation (5.65√S0 & 4D) | 14% | |
| Hardness (Rockwell C) | 27-35 | |
| Impact strength (≤ -29°C) | 27 J av (20 J min) |
| Property | Value |
|---|---|
| Density (kg/m³) | 8440 |
| Magnetic permeability (20°C) | < 1.005 (1.002 typical) |
| Young's modulus (kN/mm²) | 179 |
| Specific electrical resistance, 20°C (µΩ.m) | 0.62 |
| Mean coefficient of thermal expansion, 20-100°C (m/m/°C) | 13.4 x 10⁻⁶ |
| Specific heat, 20°C (J/kg.K) | 418 |
| Thermal conductivity, 20°C (W/m.K) | 17.5 |
| Curie temperature (°C) | -90 |
Equivalents & cross-references
Standard designations
- UNS
- N05500Unified Numbering System
- Werkstoff
- 2.4375German/European material number
- BS
- 3072-3076 NA18British Standard nickel alloy NA18
- ASTM
- B865Rod, bar, wire and forging stock
- AMS
- 4676Bar, rod and wire
- DIN
- 17743German standard
- NACE
- MR0175 / ISO 15156Sour service
Alloy K-500 is also designated UNS N05500, Werkstoff 2.4375, BS 3072-3076 NA18, ASTM B865, AMS 4676, DIN 17743 and NACE MR0175 / ISO 15156.
Trade name equivalents
-
Monel K-500
Special Metals Corporation
Monel K-500 is a trade name of Special Metals Corporation for Alloy K-500.
Common questions
What is the UNS number for Alloy K-500?
Alloy K-500 is a precipitation-hardenable nickel-copper alloy covered by UNS N05500, Werkstoff No. 2.4375, BS 3072-3076 (NA18), ASTM B865, AMS 4676 and DIN 17743, and is listed in NACE MR0175/ISO 15156. Langley Alloys predominantly supplies it in the hot worked and precipitation treated condition, which gives the optimum combination of high strength and ductility across the size range. Strength is developed by adding aluminium and titanium and age hardening to precipitate gamma-prime Ni3(Ti,Al) particles. It is stocked as bar; plate, tube and fittings are available on enquiry, and forgings and castings are to order.
What is Alloy K-500 used for?
Alloy K-500 is used for marine shafts, propellers, fasteners, gyroscopes and springs; oil and gas pump shafts, valve stems, drill collars and instrumentation; and process industry doctor blades and scrapers handling organic acids, caustic soda and dry chlorine. It is also used for sensors, electronic components and heat exchanger components. The combination of very low corrosion rates in high-velocity seawater and high strength makes it well suited to marine shafts.
Is Alloy K-500 non-magnetic?
Alloy K-500 has very low magnetic permeability (below 1.005) and is effectively non-magnetic down to about its Curie temperature of around minus 90C, below which it becomes ferromagnetic. This makes it useful where a strong, non-magnetic material is needed.
What is Monel K-500?
Monel K-500 is a registered trade name of Special Metals Corporation for UNS N05500, a precipitation-hardened nickel-copper alloy. Langley Alloys stocks this alloy as Alloy K-500 and supplies it to ASTM B865, AMS 4676, and NACE MR0175/ISO 15156.
Is Alloy K-500 the same as Monel K-500?
Yes. Alloy K-500 is the generic designation for UNS N05500, the same material sold by Special Metals Corporation as Monel K-500. Langley Alloys stocks Alloy K-500 to ASTM B865, AMS 4676, DIN 17743, and NACE MR0175/ISO 15156.
What is the UNS number for Monel K-500?
The UNS number for Monel K-500 is N05500. It is also designated Werkstoff No. 2.4375, BS NA18, ASTM B865, AMS 4676, and DIN 17743. Langley Alloys stocks this alloy as Alloy K-500.
What is the density of Alloy K-500?
Alloy K-500 has a density of approximately 8.44 g/cm³ (8440 kg/m³).
Datasheets
Monel for seawater and chemical service
Alloy K-500, also known as Monel K-500, is a nickel-copper alloy age-hardened for higher strength than standard Monel 400 while keeping its excellent seawater and chemical corrosion resistance.
First developed over a century ago, it remains a go-to for marine shafts, fasteners, and pump and valve components that must stay strong and corrosion-free in seawater and aggressive chemicals.
Visit our YouTube channelAlloy K-500 is refined by Electro Slag Refining (ESR); bars are supplied peeled and polished to 125CLA or better, with each bar ultrasonically tested and visually inspected.
Processing capability
Cutting
Automated band sawing to 650mm section. CNC sawing at all sites.
Cutting servicesFirst-stage processing
Turning, boring and grinding undertaken in-house.
Processing servicesInspection & testing
Each bar ultrasonically tested and visually inspected.
Inspection & testing
Tools for this grade
Sour-service screen (NACE MR0175)
Sour-Service Screen
Work out whether a service is sour from the H2S partial pressure, and see each alloy's NACE MR0175 / ISO 15156 status and hardness limit. A first-pass screen for oil & gas material selection - the full environmental envelope for a grade is set in ISO 15156-3 Annex A.
Candidate grade
| Grade | Family | NACE status | Hardness limit |
|---|
First-pass screen only. This shows whether the service is sour (from H2S partial pressure) and each material group's NACE MR0175 hardness limit and general suitability. It does not reproduce the full environmental windows (maximum H2S partial pressure, temperature, chloride, in-situ pH per grade) - those are in ISO 15156-3 Annex A and must be checked there for the specific grade, product form and condition. Qualification also depends on heat treatment, cold work and welding.
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