Monel K500 (UNS N05500): Age-Hardened Nickel-Copper Alloy for Valve Trim, Stems & High-Strength Instrumentation Components
Monel K500 is an age-hardenable (precipitation-hardenable) nickel-copper alloy, designated UNS N05500 and W.Nr 2.4375, essentially Monel 400 with added aluminum and titanium, which lets it be heat-treated to roughly three times the yield strength of Monel 400 while keeping the same nickel-copper corrosion resistance. Crestflo specifies this grade for the high-strength parts of its instrumentation valve line, valve stems and trim, where the extra strength, hardness and galling resistance of K500 are required, backed by heat/lot-number traceability and EN 10204 material certificates and delivered US-serving in 6-8 weeks. The composition, mechanical and corrosion values below are standard published data for the alloy, per the applicable ASTM specification and customizable to requirement.
> Scope: Monel K500 here means the high-strength nickel-copper instrumentation and valve-component alloy (UNS N05500), not the lower-strength Monel 400 fitting and tubing grade, and not aerospace mill bar/plate. Crestflo offers K500 as valve trim and stems and other high-strength instrumentation components, not as loose mill bar, sheet, plate or fasteners.
Request a Monel K500 Quote · Request a Sample · sales@crestflousa.com · +1 346 594 9005 (Houston, TX)
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Monel K500 Also Known As: UNS N05500, K-Monel & W.Nr 2.4375
On drawings, datasheets and purchase orders the same alloy is called out under several trade names and standard designations. Whether a print reads "Monel K-500," "K-Monel," "Alloy K500" or "N05500 alloy," it refers to this one age-hardenable nickel-copper grade.
| Designation type | Value |
|---|---|
| Trade / common names | Monel K500, Monel K-500, Monel K 500, K-Monel, K Monel, KMonel, Alloy K-500, Alloy K500, Nickel Alloy K500 |
| UNS number | UNS N05500 (N05500) |
| Werkstoff (W.Nr) | 2.4375 |
| DIN designation | NiCu30Al |
| Alloy family | Nickel-copper, precipitation (age) hardenable |
| Base relationship | Monel 400 + aluminum + titanium (gamma-prime hardening) |
| Spaced / reversed forms | K500 Monel, K-500 Monel, K500 nickel-copper alloy, N05500 alloy |
UNS N05500 (the US designation) and W.Nr 2.4375 (the European designation) describe the identical alloy, so a part specified either way is the same Monel K500.
Monel K500 Chemical Composition (Nickel-Copper + Al/Ti, per ASTM B865)
What separates K500 from Monel 400 is the deliberate addition of aluminum and titanium: on aging, these form a fine gamma-prime Ni₃(Al,Ti) precipitate that hardens the alloy without sacrificing its nickel-copper corrosion resistance. Nominal element ranges follow ASTM B865.
| Element | wt % (per ASTM B865) |
|---|---|
| Nickel (Ni) | 63.0 min |
| Copper (Cu) | 27.0–33.0 |
| Aluminum (Al) | 2.30–3.15 |
| Titanium (Ti) | 0.35–0.85 |
| Iron (Fe) | 2.0 max |
| Manganese (Mn) | 1.5 max |
| Carbon (C) | 0.25 max |
| Silicon (Si) | 0.50 max |
| Sulfur (S) | 0.010 max |
Ranges are per the applicable ASTM product-form specification; Crestflo confirms the actual heat chemistry, the full chemical analysis, on the EN 10204 material test certificate supplied with every order.
Monel K500 Mechanical Properties: Tensile, Yield & Hardness (Age-Hardened vs Annealed)
Monel K500's strength is condition-dependent, it is soft and formable in the annealed state and reaches its high strength only after the aging heat treatment, not by cold work alone. The age-hardened figures below are the reason the alloy is chosen for valve stems, trim and fasteners over Monel 400.
| Property | Annealed | Age-hardened | Unit |
|---|---|---|---|
| Tensile strength | ~90–110 (620–760) | ~130–180 (900–1240) | ksi (MPa) |
| Yield strength (0.2% offset) | ~40–60 (275–415) | ~90–120 (620–830) | ksi (MPa) |
| Elongation | ~35–45 | ~20–30 | % |
| Hardness | ~65–80 HRB | ~24–35 HRC (~250–330 HB) | — |
| Modulus of elasticity | ~180 (26) | ~180 (26) | GPa (10⁶ psi) |
Values are typical standard published ranges for the alloy and vary with section size and heat-treat condition; certified properties for a given heat are stated on the material test certificate. In the age-hardened condition K500 reaches yield strengths comparable to or above many carbon and stainless steels while adding the seawater and hydrofluoric-acid corrosion resistance those steels lack.
Monel K500 Age Hardening & Heat Treatment (Gamma-Prime Precipitation)
K500 is strengthened by a solution anneal followed by a controlled aging cycle, during which a fine gamma-prime Ni₃(Al,Ti) phase precipitates through the nickel-copper matrix. Because the achieved strength and hardness depend on that thermal cycle and on section size, the same alloy can be supplied soft for machining and forming and then aged to full strength, which is why K500 properties are always quoted against a stated condition rather than as a single number.
Monel K500 Physical Properties: Density, Melting Range & Magnetic Permeability
The physical constants of K500 track closely to Monel 400, it is a dense nickel-copper alloy with low magnetic permeability that can be essentially non-magnetic depending on condition and temperature.
| Property | Value | Unit |
|---|---|---|
| Density | 8.44 (0.305) | g/cm³ (lb/in³) |
| Melting range | 1315–1350 (2400–2460) | °C (°F) |
| Modulus of elasticity | ~180 (26) | GPa (10⁶ psi) |
| Thermal conductivity | ~17.4 | W/m·K |
| Maximum continuous service temperature | ~480–540 (900–1000) | °C (°F) |
| Magnetic permeability | Low; near non-magnetic in many conditions | — |
| Structure | Face-centered cubic (nickel-copper matrix, gamma-prime hardened) | — |
Physical data is standard published nominal data for the alloy; the grade retains useful strength from cryogenic temperatures upward, with a maximum service temperature (upper temperature limit) of roughly 480–540°C (900–1000°F) for continuous use, values per applicable data and customizable to requirement.
Monel K500 Corrosion Resistance: Seawater, HF Acid & Sour Service (NACE MR0175 / ISO 15156)
Because aging changes the mechanical properties but not the base chemistry, K500 shares the nickel-copper corrosion behavior of Monel 400: excellent resistance to seawater, brackish and marine environments, hydrofluoric acid, and dilute sulfuric and hydrochloric acids, with strong resistance to chloride stress-corrosion cracking. The table summarises typical service suitability from standard alloy corrosion literature.
| Media / service | Suitability | Note |
|---|---|---|
| Seawater / brackish water | Excellent | High-strength marine and offshore hardware |
| Hydrofluoric acid (HF) | Excellent | A defining nickel-copper application |
| Sulfuric acid (H₂SO₄), dilute | Good | Reducing conditions favor nickel-copper |
| Hydrochloric acid (HCl), dilute | Good | Better than stainless in reducing acids |
| Alkalis / caustics | Excellent | Resists caustic and neutral salts |
| Chloride stress-corrosion cracking | Highly resistant | Key advantage over austenitic stainless |
| Sour / H₂S service | Suitable with hardness control | Per NACE MR0175 / ISO 15156, commonly ≤ HRC 35 |
For sour service, UNS N05500 is used under NACE MR0175 / ISO 15156 when hardness is controlled, typically to a maximum of HRC 35 in the correct heat-treat condition; confirm the level and hardness limit in the standard for your application. Note that PREN (the pitting-resistance index used for chromium-molybdenum stainless and duplex) is not the governing measure for a nickel-copper alloy, K500's corrosion resistance is set by its nickel-copper chemistry, not by a PREN value. See the NACE MR0175 and ISO 15156 standard pages, the sour-service selection guide, and the corrosion-by-media × alloy matrix.
Monel K500 vs Monel 400: Strength, Hardness & When to Choose Each
Monel K500 and Monel 400 share the same nickel-copper corrosion resistance, so the choice between them is a strength decision, not a corrosion decision. K500 adds aluminum and titanium to become age-hardenable; Monel 400 is the solid-solution grade used for fitting bodies, ferrules and tubing.
| Property | Monel 400 (N04400) | Monel K500 (N05500) |
|---|---|---|
| Age-hardenable? | No (solid solution) | Yes (gamma-prime Ni₃(Al,Ti)) |
| Yield strength (typical) | ~25–50 ksi | ~90–120 ksi age-hardened |
| Hardness | ~110–150 HB | ~24–35 HRC age-hardened |
| Corrosion resistance | Nickel-copper (seawater, HF, acids) | Same nickel-copper resistance |
| Typical instrumentation use | Tube fittings, ferrules, tubing, valve bodies | Valve stems and trim, high-strength components |
Choose Monel 400 for the corrosion-wetted body and connection forms; choose K500 where the same corrosion resistance must come with much higher strength and hardness, most often for valve stems, trim and fasteners. For the full lower-strength grade, see Monel 400; for the broader family decision, read the Inconel vs Monel guide.
Monel K500 Fabrication: Machinability, Weldability & Anti-Galling
Like all nickel-copper alloys, K500 work-hardens and is prone to galling on threaded and sliding surfaces, which shapes how it is machined, welded and finished.
- Machinability: K500 is machinable and is usually machined in the age-hardened condition for the best surface and chip control; it work-hardens, so rigid setups, sharp tooling and positive, uninterrupted feeds are used.
- Weldability: the alloy is weldable, gas-tungsten-arc welding being common; because weld heat affects the age-hardened strength, components are aged after welding where full strength is required.
- Galling and anti-galling finishes: nickel-copper mating parts such as stems and threaded trim can gall, so Crestflo offers silver anti-galling plating and other finishing on K500 components. In-house CNC / VMC / EDM machining produces the finished valve components.
Monel K500 Applications: Valve Stems, Trim, Fasteners & Marine Hardware
The combination of Monel-grade corrosion resistance with high strength makes K500 the standard choice wherever a nickel-copper part also has to carry load or resist wear.
- High-strength valve stems and trim for corrosive and marine service.
- Fasteners and bolting where nickel-copper corrosion resistance must come with high strength.
- Springs and other components needing strength plus corrosion resistance.
- Pump and propeller shafts, oil-and-gas downhole and marine hardware.
Within instrumentation, K500's role is the high-strength valve component, see the instrumentation valves hub, while the corrosion-wetted fitting and tubing forms are supplied in Monel 400. Typical end markets include oil & gas and marine & shipbuilding.
Monel K500 Standards & Specifications (ASTM B865, AMS 4676/4677, NACE)
The alloy is covered by product-form and application standards that educate the grade; Crestflo builds its instrumentation components from certified material to these specifications.
| Standard | Scope | Applies to K500? |
|---|---|---|
| ASTM B865 | Rod, bar and wire (UNS N05500) | Yes, primary product-form spec |
| AMS 4676 / AMS 4677 | Bar and forgings (aerospace) | Yes, where an AMS callout is specified |
| QQ-N-286 | Legacy US federal specification | Yes, historical equivalent |
| NACE MR0175 / ISO 15156 | Sour-service hardness limits (≤ HRC 35 typical) | Yes, with hardness control |
| ASME B16.34 / API | Valve pressure-boundary design and testing | Applies to the finished valve, not the raw grade |
| EN 10204 | Material test certificate (3.1 / 3.2) | Yes, supplied with every order |
Values and grades are per the applicable ASTM/AMS specification. Note that ASTM F1387 is a compression tube-fitting performance standard used for Crestflo's fitting products (in Monel 400 for nickel-copper); Crestflo valve components qualify to ASME B16.34 with API test practice. Material certificates accompany every order, see EN 10204 MTC.
Monel K500 Product Forms from Crestflo: Valve Trim, Stems & Nickel-Copper Instrumentation
Crestflo specifies UNS N05500 where the extra strength of an age-hardened nickel-copper alloy is required, principally as high-strength valve components. For the corrosion-wetted fitting, ferrule and tubing forms in nickel-copper, the standard grade is Monel 400.
- Monel K500 valve trim and stems, high-strength stems and trim within Crestflo instrumentation valves (needle, ball, check and manifold), where K500 replaces a lower-strength trim material for demanding service. Valve pressure-boundary design follows ASME B16.34 with API seat-leak and test practice.
- Monel 400 tube & compression fittings, for nickel-copper fitting bodies and ferrules, Monel 400 (UNS N04400) is the standard grade, with compression ends performance-qualified per ASTM F1387.
- Monel 400 instrumentation valves and Monel 400 tubing, the nickel-copper valve and tubing forms.
Every Crestflo nickel-copper part carries a heat/lot number and ships with an EN 10204 material test certificate, with material verified by PMI. Sizes, trim material and thread standard are configured to requirement.
Why Crestflo for Monel K500
We Engineer Confidence, and for a high-strength alloy like K500 that means PMI-verified chemistry, honest sourcing and real interchange, published as extractable specs rather than a buried PDF. As a US-serving Monel K500 supplier and manufacturer, not a mill-product stockist or distributor, Crestflo supplies the finished valve components, not loose bar.
- Drop-in interchange for Swagelok®, Parker®, Hoke® and Hy-Lok® across the nickel-copper instrumentation range, dimensional interchange, with compression fitting ends backed by ASTM F1387 performance qualification (interchange/equivalent parts, not "compatible/intermix"). Request your Swagelok®/Parker® cross-reference from our engineering team via the cross-reference page.
- Lead time 6-8 weeks versus 20+ weeks typical for the majors, see the lead-time capability.
- Full traceability, heat/lot number on every part, EN 10204 MTC 3.1 as standard (3.2 on request), PMI to confirm the material is genuinely N05500, plus in-house testing.
- NACE MR0175 / ISO 15156 hardness-controlled material options, plus silver anti-galling plating and finishing for stems and threaded trim.
- ISO 9001 / 14001 / 45001 & PED certified; in-house CNC / VMC / EDM machining, small MOQ and private-label options.
- The heritage behind the brand: Crestflo is the instrumentation division of a four-decade-old, Government-of-India-recognized export house with a proven Middle-East delivery track record, new manufacturing, deep export pedigree. Read more about Crestflo.
Stock & delivery: ready stock for standard items · made-to-order for specials · 6-8 week delivery. Origin: Indian origin; US / European melt available on request, with full material traceability (origin & compliance).
Buyers: Request a Quote or Sample (end users, EPC, panel fabricators) · Talk to an engineer / send a print (equipment manufacturers, OEMs) · Become a distributor.
Monel K500 FAQs
What is Monel K500?
Monel K500 is an age-hardenable nickel-copper alloy, UNS N05500 / W.Nr 2.4375, Monel 400 with added aluminum and titanium so it can be precipitation-hardened to much higher strength while keeping the same corrosion resistance. It is used for high-strength valve stems, trim, fasteners and marine hardware.
What is the chemical composition of Monel K500?
Nominally 63% minimum nickel, 27-33% copper, 2.30-3.15% aluminum, 0.35-0.85% titanium, up to 2% iron, up to 1.5% manganese and up to 0.25% carbon, per ASTM B865. See the composition table above for the full ranges.
How hard is Monel K500?
In the age-hardened condition K500 is typically about 24-35 HRC (Rockwell C hardness), roughly 250-330 HB (Brinell); it is much softer when annealed and is hardened by an aging heat treatment rather than by cold work alone.
What are the key differences between Monel K500 and Monel 400?
Both share the same nickel-copper corrosion resistance, but K500 adds aluminum and titanium to become age-hardenable, giving roughly triple the yield strength and higher hardness. K500 is used for high-strength parts such as stems, trim and fasteners, while Monel 400 is the fitting and tubing grade. See the Monel 400 material page for the lower-strength grade.
Is Monel K500 stronger than steel?
Age-hardened K500 reaches yield strengths comparable to or above many carbon and stainless steels while adding the seawater and hydrofluoric-acid corrosion resistance most steels lack, which is why it is specified for high-strength corrosion-resistant hardware.
What material is equivalent to Monel K500?
By designation, UNS N05500 equals W.Nr 2.4375 (DIN NiCu30Al), covered by ASTM B865, legacy QQ-N-286 and aerospace AMS 4676/4677. There is no true drop-in substitute; the nearest lower-strength alloy is Monel 400 (UNS N04400).
Is Monel K500 suitable for NACE sour service?
Yes, under NACE MR0175 / ISO 15156 when hardness is controlled, commonly to a maximum of HRC 35 in the correct heat-treat condition; confirm the level and hardness limit in the standard for your application. Crestflo supplies NACE-compliant, hardness-controlled K500 valve components.
Can I get tube fittings or tubing in Monel K500?
For nickel-copper fitting bodies, ferrules and instrumentation tubing, the standard grade is Monel 400; K500 is specified for high-strength valve components such as stems and trim where the extra strength is needed. Crestflo routes those fitting and tubing forms to Monel 400 and supplies K500 as valve trim and stems.
Do you provide material certificates for Monel K500?
Yes. Every part carries a heat/lot number with an EN 10204 3.1 material test certificate as standard and 3.2 on request, plus PMI to confirm the material is genuinely UNS N05500.
What is the lead time and minimum order for Monel K500?
Price and cost are by quotation, components are made to order and offered for sale by RFQ, not through an online cart. Ready stock applies to standard items, with made-to-order for specials and 6-8 week delivery. Standard product is of Indian origin; US/European melt is available on request with full traceability. Small MOQ and private label are available, submit an RFQ with your form, size and line conditions.
Related Alloys & Resources
- Monel 400, the lower-strength solid-solution nickel-copper grade for fittings, ferrules and tubing.
- Inconel 625 · Inconel 825, nickel alloys for higher-temperature and broader corrosion service.
- Hastelloy C-276 · Nickel 200/201, related nickel-base grades.
- Inconel vs Monel, the corrosion-alloy matrix and the PREN comparison table decision guides.
- Browse the full range from the instrumentation valves hub and the materials hub.
Request a Monel K500 Quote
Send your requirement, valve trim and stems in K500, or nickel-copper fittings and tubing, with size, end connections and line conditions, and the Crestflo Engineering Team will return a configured part number, ratings and price.
Request a Quote · Request a Sample · Browse the materials hub sales@crestflousa.com · +1 346 594 9005 · Houston, TX
Datasheet / spec sheet, technical data & CAD available to customers on request. Reviewed by the Crestflo Engineering Team. Monel® is a registered trademark of Special Metals Corporation; Swagelok® and Parker® are trademarks of their respective owners.