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Monel K500 Round Bars - ASTM B865 UNS N05500 High-Strength Bar Stock Supplier
Nicorex Alloys is an ISO 9001 / ISO 14001 certified supplier in Mumbai, India. We supply Alloy K500 bar stock with EN 10204 3.1 mill test certificates and PMI reports.
Monel K500 round bar is a precipitation-hardened nickel-copper-aluminium alloy bar stock manufactured to ASTM B865 / ASME SB865. Age hardening through aluminium and titanium additions delivers approximately 3× yield strength and 2× tensile strength compared to other alloys, while retaining equivalent seawater and reducing-acid corrosion resistance. This alloy (UNS N05500, Werkstoff Nr. 2.4375) is non-magnetic at room temperature with a Curie temperature of -29°C (-20°F), and is NACE MR-01-75 listed for sour gas service. Density is 8.44 g/cm³. In the age-hardened condition, the K-Monel bar reaches 965 MPa (140 ksi) tensile strength and 690 MPa (100 ksi) yield strength with Rc 24 min hardness. Cold-drawn and aged bars achieve up to 1170 MPa (170 ksi) tensile. The alloy retains ductility down to cryogenic temperatures (-196°C) and maintains age-hardened properties up to 480°C (900°F). Key applications include propeller shafts, drill collars, pump shafts, and high-strength fasteners in marine and oil-and-gas environments.
Diameters span 4 mm to 500 mm in lengths of 1000-6000 mm per ASTM B865, AMS 4676, and QQ-N-286. Available forms include round bar, hex bar, flat bar, square bar, forged bar, bright bar, and hollow bar in hot-rolled, cold-drawn, and centreless-ground finishes. Conditions: annealed, age hardened, and hot finished.
Monel Alloy K500 Bar Specifications
Monel K500 bar, also known as UNS N05500, specifications, like standard, dimensions, conditions, tolerances, surface finishes, and more, are listed below:
| Specification | ASTM B865 / ASME SB865 |
|---|---|
| AMS / Federal | AMS 4676 / QQ-N-286 |
| Round Bar Dia. | 4 mm – 500 mm |
| Hex Bar | 6 mm – 57 mm A/F |
| Length | 1000 – 6000 mm, cut-to-length |
| Condition | Annealed (A), Age Hardened (AH), Hot Finished (HF) |
| Finish | Bright Ground, Black, Peeled, Polished, Rough Turned |
| Tolerance | h8, h9, h10, h11 per ISO 286-2 |
| Forms | Round, Hex, Flat, Square, Forged, Bright, Hollow |
Chemical Composition of Monel K500 Bar & Rod
ASTM B865, UNS N05500 specifies the chemical composition limits for corrosion-resistant, precipitation-hardenable nickel-copper alloy Monel K500 bars:
| Property | Tensile (min) | Yield 0.2% (min) | Elongation (min) | Hardness |
|---|---|---|---|---|
| Annealed | 655 MPa (95 ksi) | 276 MPa (40 ksi) | 25% | 140-185 HB |
| Age Hardened | 965 MPa (140 ksi) | 690 MPa (100 ksi) | 15% | Rc 24 min |
| CD + Aged | 1035-1170 MPa | 760-1035 MPa | 8-12% | Rc 30-38 |
Age hardening multiplies yield strength from 276 MPa to 690 MPa and tensile strength from 655 MPa to 965 MPa. Cold-drawn and aged bars push to 1170 MPa tensile and Rc 38 hardness.
Physical Properties of Nickel Alloy K500
Key physical characteristics of Monel K500, such as density, melting range, and Curie temperature, define its performance in demanding applications:
| Property | Value | Unit |
|---|---|---|
| Density | 8.44 | g/cm³ |
| Melting Range | 1315-1350 | °C |
| Curie Temperature | -29 | °C |
| Thermal Conductivity (25°C) | 17.5 | W/m·°C |
| Elastic Modulus | 179 | GPa |
| Thermal Expansion (20-100°C) | 13.7 × 10⁻⁶ | /°C |
| Electrical Resistivity (25°C) | 0.615 | µΩ·m |
Unlike Monel 400, K500 is non-magnetic at room temperature. This is a key selection factor for subsea instruments, MWD/LWD tool housings, and magnetic survey tools where ferromagnetic interference cannot be tolerated.
Monel K500 Bar Equivalent Grades
Monel K500 Bar has Werkstoff Nr. 2.4375 and its equivalent designations for UNS N05500 bar are listed in the given table:
| Property | UNS | Werkstoff Nr. | JIS |
|---|---|---|---|
| Value | N05500 | 2.4375 | NW 5500 |
Get Monel K500 Round Bars at Competitive Prices
Available Forms of Monel K500 Bar & Rod
Monel K500 bar is available in the following product forms. Age-hardened condition is available for all forms on request:
Monel K500 Round Bar
Monel K500 Hex Bar
Monel K500 Flat Bar
Monel K500 Square Bar
Monel K500 Forged Bar
Monel K500 Bright Bar
Monel K500 Hollow Bar
Age Hardening & Heat Treatment of Monel K500 Bar
Solution anneal hot-finished bar at 982°C (1800°F) minimum; cold-worked bar at 1038°C (1900°F) minimum. Water quench immediately to prevent partial precipitation. Keep the time at temperature short to avoid grain growth.
Age harden at 593-621°C (1100-1150°F) for 16 hours. Furnace cool at 8-14°C/hr to 482°C (900°F), then air cool. Atmosphere control is essential; free-air ageing degrades corrosion resistance. Properly aged bars reach Rc 24-38 depending on prior cold work. Over-ageing above 621°C reduces properties; re-solution annealing is needed to recover.
K500 in the age-hardened condition has a greater tendency toward stress-corrosion cracking than Monel 400 in some environments. Proper ageing and hardness control are critical for NACE MR-01-75 compliance.
Industries Using Monel K500 Round Bar
Monel K500 round bars provide high-strength, corrosion-resistant performance for demanding marine, offshore, oil and gas, and industrial applications.
Monel 400 bars and rods are specified across industries where solid-section corrosion-resistant material is needed for shafts, fasteners, valve components, and machined parts. These bars are used in the following 6 key applications:
-
Marine & Offshore: Propeller shafts, centrifugal pump shafts in seawater, anchor chain components, and submarine valve stems.
-
Oil & Gas: Drill collars, MWD/LWD tool housings, and choke valve stems used in sour service (NACE MR-01-75).
-
Chemical & Petrochemical: Reactor bolts, parts for spring-loaded safety valves, and mixer/agitator shafts used with corrosive slurries.
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Aerospace: Rods for landing gear actuators and shafts for hydraulic cylinders (per AMS 4676).
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Power Generation: Bolts that hold turbine blades in place and shafts for feedwater pumps.
How to Order Monel K500 Round Bar & Rod
To order Monel K500 Round Bar, the following 12 details are required:
- Product Form: Round Bar, Hex Bar, Flat Bar, Square Bar, Forged Bar
- Diameter / Size: mm or inches; A/F for hex
- Length: standard or custom cut-to-length
- Quantity: kg, MT, pieces, or running metres
- Condition: Annealed, Age Hardened, Hot Finished
- Surface Finish: Bright Ground, Black, Peeled, Polished
- Tolerance: h8, h9, h10, h11 per ISO 286-2
- Standard: ASTM B865 / ASME SB865 / AMS 4676 / QQ-N-286
- NACE Compliance: MR-01-75 if for sour service - specify hardness limit
- Additional Testing: PMI, UT, MPI, NACE SSR test, TPI
- Certification: EN 10204 3.1 / 3.2, NACE compliance cert
- Packaging & Delivery: domestic / export-grade
Frequently Asked Questions
What is the Difference Between Monel K500 and Monel 400 Bar?
K500 contains aluminium (2.30-3.15%) and titanium (0.35-0.85%) that enable precipitation hardening. After ageing, K500 delivers 3× yield strength (690 vs 207 MPa) and 2× tensile (965 vs 517 MPa) compared to Monel 400 annealed. Choose K500 when high strength is critical alongside corrosion resistance.
Is Monel K500 Bar Magnetic?
No. K500 is non-magnetic at and above room temperature (Curie temp -29°C). This differentiates it from Monel 400, which is slightly ferromagnetic.
What is the Age-Hardening Cycle for Monel K500 Bar?
Solution anneal at 982-1038°C, water quench. Age at 593-621°C for 16 hours, furnace cool at 8-14°C/hr to 482°C, air cool. Aged K500 achieves Rc 24-38.
What Makes Monel K500 Suitable for Pump Shafts?
High yield (690 MPa min aged), excellent fatigue resistance, and corrosion rates below 1 mpy in flowing seawater. These properties prevent shaft deflection, pitting, and SCC under cyclic loading.
What is the Maximum Temperature for Monel K500 Bar?
Age-hardened properties hold up to 480°C (900°F). Above this, over-ageing reduces strength. The alloy stays ductile down to -196°C.
What Welding Filler Metal is Used for Monel K500?
GTAW with ERNiCu-7 is standard. Note: ERNiCu-7 weldments will not match K500 base-metal strength because the filler is not age-hardenable. Solution anneal before ageing; stress-relieve weldments before age hardening.