Precision-Cut Monel K500 Round Steel Excellent Fatigue Resistance, High Tensile Strength for Industrial Machinery Parts

Monel K500 Round Steel is a high-performance nickel-copper alloy renowned for its exceptional combination of high tensile strength, excellent fatigue resistance, and outstanding corrosion resistance. This precipitation-hardenable alloy is ideal for demanding industrial machinery applications where reliability and durability are critical. Below is a comprehensive overview of its product information.

► Overview of Monel K500

Monel K500 (UNS N05500) is a age-hardenable nickel-copper alloy that retains the excellent corrosion resistance of Monel 400 but with significantly enhanced mechanical properties due to additions of aluminum (Al) and titanium (Ti). This alloy is characterized by its high strength, good toughness over a wide temperature range, and excellent performance in corrosive environments. It is particularly suitable for precision-cut components in industrial machinery, marine engineering, aerospace, and chemical processing equipment.

► Chemical Composition (%)

The typical chemical composition of Monel K500 is as follows:

The addition of aluminum and titanium enables precipitation hardening through the formation of γ' (Ni₃(Al, Ti)) phases during heat treatment, significantly enhancing strength and hardness.

► Mechanical Properties

Monel K500 round steel exhibits impressive mechanical properties, both in annealed and age-hardened conditions:

• Tensile Strength: ≥1000 MPa (can reach up to 1200 MPa after age-hardening)

• Yield Strength (0.2% Offset): ≥690 MPa (can exceed 790 MPa in age-hardened condition)

• Elongation (A5 %): ≥20%

• Hardness: 265-310 HB (typical), or approximately HRC 25-35 after aging treatment

• Fatigue Strength: Excellent resistance to fatigue, particularly in corrosive environments; surface passivation film inhibits crack propagation

• Impact Toughness: Good fracture toughness (≥80J at -196°C)

Its yield strength is approximately three times that of Monel 400, and its tensile strength is about double.

► Physical Properties

• Density: 8.05 g/cm³ to 8.80 g/cm³

• Melting Point: 1300°C - 1350°C

• Elastic Modulus: 26,000 ksi

• Thermal Conductivity: 22 W/m·°C

• Magnetic Properties: Essentially non-magnetic

► Key Characteristics and Advantages

1. High Strength and Hardness: The primary advantage of Monel K500 is its significantly enhanced strength and hardness compared to other nickel-copper alloys, achieved through age-hardening treatments without compromising its corrosion resistance.

2. Excellent Fatigue Resistance: It demonstrates superior resistance to fatigue, especially in corrosive environments like seawater. Its surface passivation film effectively inhibits crack initiation and propagation.

3. Outstanding Corrosion Resistance: Similar to Monel 400, it offers excellent resistance to a wide range of corrosive media, including seawater, hydrofluoric acid, fluorine gas, hot concentrated alkalis, acids, salts, and alkaline solutions. It is highly resistant to chloride-induced stress corrosion cracking.

4. Good Wear Resistance: Exhibits approximately 30-50% better wear resistance compared to standard stainless steels, particularly in abrasive environments containing sand or particles.

5. Wide Temperature Applicability: Maintains good mechanical properties from sub-zero temperatures up to about 480°C (900°F). Its long-term organizational stability makes it suitable for applications up to 750°C.

6. Non-Magnetic: This property is valuable for applications in electronics and certain marine and aerospace instruments where magnetism is undesirable.

► Applications in Industrial Machinery

Monel K500 round steel is precision-cut for various critical components in demanding industries5:

• Pump Shafts and Impellers: Especially in marine and chemical applications for handling seawater, acids, and alkalis due to high strength and corrosion resistance.

• Valves and Valve Components: Used in chemical processing, oil and gas production (e.g., wellhead components, instrument housings).

• Fasteners and Springs: Marine bolts, springs requiring high strength and corrosion fatigue resistance.

• Scraper Blades and Doctor Blades: In paper manufacturing equipment and industrial scrapers.

• Wear Rings and Bushings: In pumps and valves for abrasive/corrosive services.

• Oil & Gas Drilling Equipment: Non-magnetic drill collars, downhole tools.

• Aerospace Components: Engine parts, turbine blades under 750°C.

► Processing and Heat Treatment

Monel K500 can be strengthened by cold working and age-hardening (precipitation hardening):

• Age-Hardening Treatment: Typical aging is performed at 480-620°C for 4-16 hours, leading to precipitation of fine γ' phases (Ni₃(Al, Ti)), significantly enhancing strength.

• It is recommended to perform stress relieving after welding before proceeding with the age-hardening process.

• Cold working prior to aging can further increase strength.

► Available Forms and Specifications

• Forms: Precision-cut round steel (bars, rods), also available as plates, sheets, tubes, pipes, wires, forgings, and flanges.

• Standard Specifications:

  • ASTM B865 (Bars, Wire, Plates)

  • AMS 4676

  • UNS N05500

  • DIN 2.4375

► Why Choose Monel K500 Round Steel?

For industrial machinery parts subjected to high stresses, cyclic loading (fatigue), and corrosive environments, Monel K500 offers an exceptional combination of properties:

• Reliability: High strength and fatigue resistance ensure long service life and reduced downtime.

• Versatility: Suitable for a wide range of temperatures and harsh chemical environments.

• Performance: Superior to many stainless steels and other nickel alloys in applications requiring both mechanical strength and corrosion resistance.

Typical Mechanical Properties of Monel K500 Round Steel (Aged Condition)