UNS N05500|2.4375|Monel K500 Seamless Tube
Distinguished by the addition of Aluminum and Titanium, our Monel K500 tubing undergoes a controlled precipitation-hardening process, delivering triple the yield strength of standard Monel 400 while maintaining excellent ductility. These tubes are indispensable for mission-critical applications in subsea oil well components, marine propeller shafts, and centrifugal pump shafts. Through advanced cold-drawing and age-hardening treatments, XinZhe ensures every tube offers superior resistance to hydrogen embrittlement and stress-corrosion cracking (SCC) in sour-gas (H2S) environments.
"While Monel 400 provides excellent general corrosion resistance, Monel K500 is the definitive choice for applications requiring additional strength and hardness through precipitation aging."
What Is a Seamless Monel K500 Tube?
Monel K500 (UNS N05500) is a precipitation-hardenable nickel-copper alloy made by adding small amounts of aluminium and titanium to the Monel 400 composition. Age hardening roughly doubles the yield strength and hardness of Monel 400 while retaining the same excellent corrosion resistance in seawater, hydrofluoric acid and alkaline media — which makes K500 tubing ideal for pump shafts, valve trim and subsea hardware.
Seamless Monel K500 Tube (UNS N05500) is a high-performance nickel-copper alloy tube designed for applications requiring exceptional strength, corrosion resistance, and reliability under extreme conditions.
Monel K500 is an age-hardenable alloy derived from Monel 400. Through the controlled addition of aluminum (Al) and titanium (Ti), and a precipitation hardening process, the alloy forms sub-microscopic Ni₃(Al, Ti) phases within the matrix.
The seamless manufacturing process ensures:
Key Features and Technical Advantages
Exceptional Strength and Hardness
Age hardening roughly doubles the yield strength and hardness of Monel 400 while retaining useful ductility, allowing K500 tubing to carry high mechanical loads.
Outstanding Corrosion Resistance
Monel K500 resists seawater, hydrofluoric acid, sulphuric acid and alkaline media, and is essentially immune to chloride stress-corrosion cracking.
Wide Temperature Performance
The alloy retains its mechanical properties from cryogenic temperatures up to about 480 °C, covering both LNG and hot-process duty.
Non-Magnetic and Spark-Resistant
The alloy stays non-magnetic after age hardening and resists sparking, which suits it to instrumentation and hazardous-area hardware.
Seamless Structural Integrity
Seamless construction removes the weld seam, giving a homogeneous structure with no weak zone along the tube length.
Product Specifications and Data
| Grade | C | Mn | S | Si | Ni | Cu | Fe | Ti | Al |
| Monel 400 | ≤0.3 | ≤2.0 | ≤0.024 | ≤0.5 | ≥63.0 | 28.0-34.0 | ≤2.5 | - | - |
| Monel K-500 | ≤0.2 | ≤1.5 | ≤0.010 | ≤0.5 | ≥63.0 | 27.0-33.0 | 0.5-2.0 | 0.35-0.85 | 2.30-3.15 |
Seamless Monel K500 Tube is specifically designed to maintain its high strength and shape in high-stress applications.
| Tensile Strength | Yield Strength | Elongation | Hardness |
| ≥ 1100 MPa | ≥ 758 MPa | ≥ 20% | 26-32 HRC |
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
| 8.44 g/cm³ | 1315 - 1350 °C | 13.7 µm/m·°C (20-100°C) | 17.5 W/m·K (20°C) | 179 GPa | 0.62 x 10⁻⁶ Ω·m (20°C) |
| Nominal Outside Diameter, in. (mm) | Outside Diameter in. (mm) | Thickness of Specified Nominal Wall , % | Thickness of Specified Minimum Wall , % | |||
| Plus | Minus | Plus | Minus | Plus | Minus | |
| Over 0.400 (10) to 5/8 (16), excl | 0.005 (0.13) | 0.005 (0.13) | 15 | 15 | 30 | 0 |
| 5/8 (16) to 1 1/2 (38), incl | 0.0075 (0.19) | 0.0075 (0.19) | 10 | 10 | 22 | 0 |
| Over 1 1/2 (38) to 3 (76), incl | 0.010 (0.25) | 0.010 (0.25) | 10 | 10 | 22 | 0 |
| Over 3 (76) to 4 1/2 (114), incl | 0.015 (0.38) | 0.015 (0.38) | 10 | 10 | 22 | 0 |
| Over 4 1/2 (114) to 6 (152), incl | 0.020 (0.51) | 0.020 (0.51) | 12.5 | 12.5 | 28 | 0 |
| Over 6 (152) to 6 5/8 (168), incl | 0.025 (0.64) | 0.025 (0.64) | 12.5 | 12.5 | 28 | 0 |
| Over 6 5/8 (168) to 8 5/8 (219), incl | 0.031 (0.79) | 0.031 (0.79) | 12.5 | 12.5 | 28 | 0 |
Dimensional Standards and Tolerances
Monel K500 seamless tubes are supplied to the dimensional tolerances of ASTM B163 / B829 unless a tighter project specification applies.
Common Industrial Applications
Marine and Offshore Engineering
- Pump shafts and valve trim
- Subsea hardware components
- Seawater handling systems
Oil and Gas Industry
- Downhole instrumentation housings
- Drill-collar and logging tools
- High-strength process tubing
Chemical and Petrochemical Processing
- Pump and agitator shafts
- Valve and impeller components
- Hydrofluoric acid service parts
Aerospace and Instrumentation
- Non-magnetic instrument components
- Spark-resistant hardware
- Precision mechanical parts
Quality Assurance and Manufacturing Process
Certification
All Monel K500 tubes are supplied to ASTM B163 / ASME SB163 and ASTM B829 with EN 10204 3.1 mill test certificates. Third-party inspection (SGS, BV, TUV, Lloyd's), PMI reports and full heat-number traceability can be provided on request.
Non-Destructive Testing (NDT)
Hydrostatic or eddy-current testing is performed on 100% of tubes. Ultrasonic testing (UT) and dye-penetrant inspection (PT) are available for critical service, with records retained for each production lot.
Material Verification
Positive Material Identification (PMI) and spectrometric analysis confirm that the chemical composition matches the ordered grade. Intergranular corrosion (IGC) testing to ASTM A262 Practice E is available for austenitic and nickel-alloy tubes.
Mechanical Testing
Tensile, yield, elongation and hardness tests are carried out per heat. Flattening, flaring and reverse-bend tests verify ductility, while creep-rupture data can be supplied for high-temperature grades.
Dimensional Inspection
Outside diameter, wall thickness, ovality and straightness are measured against ASTM A1016 / A1016M or EN 10216-5 tolerances. Length, square-cut ends and end-finish conditions are verified before packing.
Monel K500 vs Monel 400 / Inconel 625 – Technical Comparison
Monel K500 is the precipitation-hardened version of Monel 400. Comparing it with Monel 400 and Inconel 625 clarifies where strength rather than corrosion resistance is the design driver.
Strengthening Mechanism
- Monel K500: age hardened with aluminium and titanium — roughly double the yield strength of Monel 400
- Monel 400: solid-solution nickel-copper alloy, no hardening treatment
- Inconel 625: nickel-chromium-molybdenum alloy with a different corrosion envelope entirely
Corrosion Resistance
K500 retains the seawater, hydrofluoric acid and alkaline resistance of Monel 400. Inconel 625 is the better choice for chloride-induced pitting and crevice attack and for high-temperature oxidation, but it does not offer the same performance in hydrofluoric acid.
Magnetic Properties
Both Monel grades remain essentially non-magnetic, and K500 stays non-magnetic after ageing — a decisive advantage for instrumentation and sensor housings.
Selection Guide
- Choose Monel K500 where high strength, hardness or wear resistance is needed in a marine or hydrofluoric acid environment
- Choose Monel 400 where corrosion resistance alone governs and higher strength is unnecessary
- Choose Inconel 625 for chloride pitting service and high-temperature oxidation
Frequently Asked Questions
What is Monel K500 seamless tube?
Monel K500 (UNS N05500) is a precipitation-hardenable nickel-copper alloy tube made by adding aluminium and titanium to the Monel 400 composition and age hardening it. It offers roughly double the yield strength of Monel 400.
What is the difference between Monel 400 and Monel K500?
Both share the nickel-copper base and the same seawater, hydrofluoric acid and alkaline corrosion resistance. K500 is age hardened, which roughly doubles its yield strength and hardness, at the cost of being more complex to weld and fabricate.
What standard covers Monel K500 tube?
Monel K500 seamless tube is supplied to ASTM B163 / ASME SB163, with ASTM B829 covering general requirements. Mechanical property requirements follow the annealed and aged condition specified by the purchaser.
What is Monel K500 tube used for?
Monel K500 is used for pump shafts and valve trim, subsea and offshore hardware, downhole instrumentation housings, and non-magnetic or spark-resistant components in marine and chemical service.
Ready to Request a Quotation?
Send your Seamless Monel K500 Tube enquiry with grade, application, size (OD and wall thickness or schedule), quantity, length, end finish and inspection requirements. Our technical team will confirm availability, testing scope and lead time.
