Table of Contents
Introduction
Monel K500 (UNS N05500) is a nickel-copper alloy known for its excellent corrosion resistance, high strength, and durability, even in extreme conditions. This alloy is a significant upgrade from Monel 400 due to the addition of aluminum and titanium, which enhance its mechanical properties through age hardening. Monel K500 is widely used in industries such as marine, oil and gas, and chemical processing, where components are exposed to harsh environments. This article explores its composition, mechanical properties, applications, and key advantages in detail.
What is Metal Monel K500?
Monel K500, also known as UNS N05500, is an age-hardenable nickel-copper alloy that combines the excellent corrosion resistance of Monel 400 with enhanced strength and hardness. This is achieved through the addition of aluminum and titanium, which enable precipitation hardening. Monel K500 offers up to three times the yield strength and double the tensile strength of Monel 400, along with resistance to corrosion fatigue and erosion. It’s widely used in marine and chemical applications due to its toughness, while stress-corrosion cracking may occur in certain environments.
What Are the Characteristics of Monel Alloy K500?
Monel K500 Chemical Composition
| Element | Percentage (%) |
| Nickel (Ni) | 63.0 – 70.0 |
| Copper (Cu) | 27.0 – 33.0 |
| Aluminum (Al) | 2.30 – 3.15 |
| Titanium (Ti) | 0.35 – 0.85 |
| Iron (Fe) | 2.0 max |
| Carbon (C) | 0.25 max |
| Manganese (Mn) | 1.5 max |
| Silicon (Si) | 0.50 max |
| Sulfur (S) | 0.01 max |
| Cobalt (Co) | 0.50 max |
Monel K500 Material Equivalent
| Standard/Specification | Equivalent Material |
| UNS | N05500 |
| ASTM | B865 |
| DIN | 2.4375 |
| BS | NA18 |
| AFNOR | NU30 |
| EN | NiCu30Al |
| ISO | NiCu30Al (UNS N05500) |
| AMS | AMS 4676 |
Monel K-500 Mechanical Properties
| Property | Value |
| Tensile Strength | 965 MPa – 1,100 MPa |
| Yield Strength (0.2% offset) | 690 MPa – 790 MPa |
| Elongation | 20% |
| Hardness (Rockwell B) | 85 – 96 HRB |
| Impact Strength | High |
| Density | 8.44 g/cm³ |
| Modulus of Elasticity | 179 GPa |
Monel K–500 Corrosion Resistance
| Environment | Corrosion Resistance |
| Seawater (Marine Environment) | Excellent, no significant corrosion rate after extended exposure |
| Sulfuric Acid (10-20%) | Resistant at room temperature, corrosion rate below 0.5 mm/year |
| Hydrochloric Acid (Dilute) | Good resistance in dilute solutions, corrosion rate < 0.3 mm/year |
| Alkalis (Caustic Solutions) | Highly resistant, negligible corrosion |
| Stress Corrosion Cracking | Some susceptibility in age-hardened condition |
| Atmospheric Corrosion | Excellent resistance, negligible corrosion in normal atmosphere |
Fabrication and Machining With Monel K–500
This alloy can be fabricated and machined using conventional methods, but its high strength and hardness after age hardening make it more challenging compared to Monel 400.
- Hot Working: Optimal temperature range is between 1600°F (870°C) and 2100°F (1150°C).
- Cold Working: Monel K-500 can be cold worked for additional strength, although care is needed to prevent cracking.
- Machining: Best performed in annealed conditions with tools designed for high-strength materials, such as carbide-tipped tools.
Heat Treatment of Monel K-500
| Heat Treatment Process | Details |
| Solution Annealing | Performed at 980°C – 1038°C (1800°F – 1900°F), followed by rapid quenching. |
| Age Hardening (Precipitation) | Typically conducted at 593°C – 649°C (1100°F – 1200°F) for a specified period. |
| Cooling | Quenching in water or air cooling after solution annealing to retain ductility. |
What Are the Advantages of Monel Alloy K-500?
Monel alloy K-500 offers several advantages that make it a preferred material for challenging environments:
- High Strength and Hardness: Compared to Monel alloy 400, K500 provides up to three times the yield strength, making it ideal for applications requiring durability.
- Corrosion Resistance: Retains excellent resistance to seawater, acids, and alkalis, crucial for marine and chemical industries.
- Fatigue and Erosion Resistance: Withstands mechanical stress and environmental wear, making it suitable for harsh, demanding applications.
- Wide Temperature Range: Performs well across a wide range of temperatures, maintaining its mechanical properties in extreme conditions.
What is Monel K500 Used For?
- Sour-Gas Service: Components for oil and gas safety lifts and valves.
- Oil-Well Tools: Drill collars, instruments, and other downhole equipment.
- Marine Applications: Propeller shafts, pump shafts, chains, cables, and valve components.
- Aerospace and Marine Fasteners: Chains, springs, and bolting used in corrosive environments.
- Industrial Scrapers and Blades: Doctor blades and impellers in chemical processing.
- Pump and Valve Components: For use in seawater and chemical environments.
Comparison with Other Monel Alloys
Monel K500 vs K400
Monel K500 offers greater strength and hardness compared to Monel 400 due to its age-hardenable properties, while both alloys share excellent corrosion resistance. K500 also has a higher tensile and yield strength, making it more suitable for high-stress applications.
Monel K500 vs 400
Monel 400 is softer and easier to machine than Monel K500 but lacks the strength and hardness that K500 gains through age hardening. K500 is more resistant to wear and erosion.
Monel K500 vs Inconel 718
While both Monel K500 and Inconel 718 are high-strength, corrosion-resistant alloys, Inconel 718 performs better at higher temperatures and in oxidation environments. Monel K500 excels in marine and chemical applications with high corrosion resistance.
Monel K500 vs SS316
Monel K500 provides superior corrosion resistance in seawater and acidic environments compared to SS316, along with significantly higher strength. However, SS316 is more cost-effective and widely used in less extreme applications.
Conclusion
Monel K500 is a top choice for applications that demand high strength and excellent corrosion resistance, especially in marine and chemical environments. Its superior mechanical properties make it more robust than Monel 400, making it ideal for critical industrial uses. If you’re looking for reliable, high-quality Monel K500 for your projects, AlloyXpert offers an extensive inventory. Contact us today for customized solutions and competitive pricing!
FAQs
Can Monel K500 Rust?
Monel K500 is highly resistant to rust due to its high nickel content, which provides excellent corrosion resistance in marine and chemical environments. It does not rust like carbon steels, but under certain conditions, it may develop surface oxidation.
Is Monel K500 Magnetic?
Monel K500 is slightly magnetic in the age-hardened condition due to the presence of nickel and copper. In its annealed condition, it is generally non-magnetic.
How Hard is Monel K-500?
This alloy has a hardness range of approximately 85-96 HRB in the Rockwell scale, making it significantly harder than Monel 400 due to the precipitation-hardening process.
What is the Heat Treatment Process of Monel K-500?
The heat treatment process for Monel K-500 involves solution annealing at 980°C to 1038°C (1800°F to 1900°F), followed by rapid quenching, and then age hardening at 593°C to 649°C (1100°F to 1200°F) to increase strength.
What is the Machinability of Monel K-500?
Monel K-500 is more difficult to machine compared to other alloys due to its high strength and work-hardening properties. Machining is best performed in its annealed condition using carbide tools and slower cutting speeds.
Read More:
What is Monel 400 Alloy (UNS N04400)?