Introduction

Monel K500 Alloy (UNS N05500 / W.Nr. 2.4375) is a precipitation-hardenable nickel-copper alloy that combines the excellent corrosion resistance of Monel 400 with significantly higher strength and hardness. Additions of approximately 2.3–3.15% aluminum and 0.35–0.85% titanium enable age hardening through the formation of gamma-prime (Ni₃Al/Ti) precipitates. This high strength Monel K500 offers yield strengths exceeding 690 MPa (100 ksi) and hardness up to 300 HB, while maintaining corrosion resistant Monel K500 performance in marine environments, seawater, hydrofluoric acid, and many chemical process environments. The alloy is non-magnetic even at low temperatures and provides excellent resistance to stress corrosion cracking and erosion in high-flow environments. Available in Monel K500 plate, sheet, bar, round bar, rod, wire, fasteners, forgings, and valve components, in hot rolled, cold rolled, cold drawn, annealed, and age hardened conditions.

Chemical components(%)

Mechanical properties

Physical properties

Monel K500 Available Products and Standard

1. GB/T 20509 (Nickel and nickel alloy plate, strip and foil)

Type:  Wire / Strip / Bar / Sheet / Tube / Forgings

Size Range:

• Monel K500 Wire: 0.1 – 15.0 mm dia

• Monel K500 Strip: 0.05 – 5.0 mm thick × 5 – 500 mm wide

• Monel K500 Bar: 8 – 355 mm dia

• Monel K500 Sheet: 0.5 – 180 mm thick

• Monel K500 Tube: Custom sizes available

Surface: Annealed, Bright, Pickled, Ground

Testing: Chemical analysis, mechanical test (tensile strength, yield strength, elongation), hardness test (HRC/HB), precipitation hardening response test, corrosion resistance test, dimensional inspection

2. ASTM B865 (Standard Specification for Precipitation Hardening Nickel-Copper Alloy Bar, Rod, Wire, and Forgings)

Grade: UNS N05500 / Monel K500 / Alloy K500

Type: Wire / Rod / Bar / Forgings / Sheet / Tube

Size Range:

• Monel K500 Wire: 0.1 – 15.0 mm dia (coils or straight)

• Monel K500 Bar / Rod: 8 – 355 mm dia (cold drawn or hot rolled)

• Monel K500 Sheet: 0.5 – 180 mm thick (cold rolled or hot rolled)

Surface: Annealed, Bright, Pickled, Polished, Ground

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hardness test, precipitation hardening response test, stress corrosion cracking test, ultrasonic test (for bar), dimensional inspection

Applications

1. Marine Engineering & Seawater Applications

• For marine propeller shafts, pump shafts, and impellers operating in high-velocity seawater, Monel K500 for marine engineering delivers excellent resistance to corrosion, erosion, and cavitation while maintaining high strength. This seawater resistant Monel K500 is widely used in stagnant or slow-moving seawater where pitting and crevice corrosion are concerns.

• For shipbuilding components including valve stems, fasteners, and bolting, Alloy K500 plate and UNS N05500 round bar provide the combination of strength and corrosion resistance required for long-term service in marine environments.

2. Oil & Gas / Offshore Equipment

• For oil well tools, drill collars, and instrumentation components in sour gas service, Monel K500 for oil and gas is NACE MR0175 (ISO 15156-3) compliant for H₂S-containing environments. This high strength nickel copper alloy resists sulfide stress corrosion cracking while maintaining non-magnetic properties.

• For offshore equipment including subsea connectors, valve trim, and safety lift components, Monel K500 forgings and fasteners withstand the harsh conditions of deepwater production.

3. Pump Shafts & Valve Components

• For pump shafts and impellers requiring both high strength and corrosion resistance, Monel K500 for pump shafts is the preferred material due to its wear resistance and galling resistance superior to Monel 400.

• For valve components including stems, trim, and seals in chemical processing and marine service, UNS N05500 bar and rod provide the hardness and dimensional stability required for reliable valve operation.

4. Fasteners & Springs

• For high-strength fasteners in marine and chemical environments, Monel K500 fasteners, bolts, and nuts offer high strength (up to 150 ksi tensile) with corrosion resistance equivalent to Monel 400.

• For springs and precision components requiring non-magnetic properties, Monel K500 wire delivers excellent fatigue resistance and spring performance.

5. Chemical Processing & Industrial Equipment

• For chemical processing equipment handling hydrofluoric acid, sulfuric acid, and alkaline solutions, Monel K500 plate and sheet maintain corrosion resistance while providing higher strength for pressure-containing applications.

• For cryogenic equipment and electronic components operating at sub-zero temperatures, Monel K500 alloy retains ductility and toughness with no ductile-to-brittle transition temperature.

FAQ – Monel K500 Alloy

Q: What is the difference between Monel 400 and Monel K500?

A: Monel K500 alloy has the same base nickel-copper composition as Monel 400 but adds approximately 2.3–3.15% aluminum and 0.35–0.85% titanium, enabling precipitation hardening. Compared to Monel 400, K500 offers roughly double the yield strength and triple the hardness, while maintaining essentially identical corrosion resistance. Monel 400 is specified for piping and general corrosion-resistant service; Monel K500 is specified where both high strength and corrosion resistance are required simultaneously—pump shafts, valve stems, fasteners, and springs.

Q: Can Monel K500 be welded, and does it require post-weld heat treatment?

A: Yes, Monel K500 alloy can be welded using TIG, MIG, and other standard processes. However, welding can cause localized softening in the heat-affected zone, reducing the strength advantage that age hardening provides. For applications requiring full strength retention, post-weld age hardening is recommended to restore precipitation-hardened properties in the weld zone.

Q: What is the maximum operating temperature for Monel K500?

A: Monel K500 alloy operates effectively from cryogenic temperatures down to -184°C (-300°F) up to approximately 450°F (232°C) in continuous service. The maximum service temperature is approximately 480°C (900°F); above this temperature, over-aging occurs and the alloy loses its precipitation-hardened strength. The alloy retains excellent mechanical properties in sub-zero temperatures with no transition temperature.

Q: Is Monel K500 suitable for sour gas service (H₂S)?

A: Yes. Monel K500 alloy is NACE MR0175 (ISO 15156-3) compliant for sour gas service. It resists sulfide stress corrosion cracking in H₂S-containing environments. For optimal performance in sour gas, the alloy should be age-hardened to a hardness below HRC 35, which is the acceptable hardness limit for UNS N05500 in sour systems.

MONO Group specializes in the supply of Monel K500 and a comprehensive portfolio of nickel‑copper alloys for marine engineering, oil & gas, chemical processing, and pump/valve applications. As a China‑based manufacturer and wholesale distributor, we offer plates, sheets, round bars, seamless tubes, welded pipes, fittings, flanges, and custom‑machined parts – all produced in accordance with ASTM, ASME, DIN, ISO, and GB specifications. We also provide cut‑to‑size, precision machining, and surface finishing services to meet your project requirements. For detailed technical datasheets, stock availability, or a competitive quotation, please contact us at info@monokj.com – our team is ready to assist with fast, expert responses.