Monel K500 Product Introduction
Product Overview
Monel K500 (UNS N05500) is a precipitation-hardening nickel-copper (Ni-Cu) superalloy derived from Monel 400, engineered to deliver significantly higher mechanical strength while retaining Monel 400’s legendary corrosion resistance. Unlike the non-hardening Monel 400, Monel K500 incorporates aluminum (2.3-3.1%) and titanium (0.35-0.85%)—elements that form nano-scale γ' phase (Ni₃(Ti,Al)) during aging heat treatment, boosting room-temperature tensile strength to ≥965 MPa (nearly double Monel 400’s ≥485 MPa). It maintains exceptional resistance to seawater, brine, and dilute acids, and performs stably up to 482°C. Widely used in high-stress corrosive environments (e.g., deep-sea oil wells, precision mechanical components) where Monel 400’s strength is insufficient, it balances "extreme strength + marine-grade corrosion resistance" like no other Ni-Cu alloy.
International Grade Comparison
Standard System | Grade | Description |
ASTM (USA) | N05500 | UNS Unified Numbering System Grade (exclusive for Monel K500) |
EN (EU) | NiCu30AlTi | EN 10088-1 Standard Grade (precipitation-hardening Ni-Cu alloy) |
JIS (Japan) | NW05500 | JIS G4902 Standard Grade (equivalent to Monel K500) |
DIN (Germany) | 2.4375 | DIN 17750 Standard Grade (strengthened variant of Monel 400’s 2.4360) |
ISO (International) | NiCu30AlTi | ISO 6363 Standard Grade (strength & corrosion dual-optimized Ni-Cu alloy) |
Physical Properties (Room Temperature & High-Temperature Highlights)
Property Indicator | Typical Value (Room Temp, After Aging) | Unit | Performance Advantage |
Tensile Strength | ≥965 | MPa | Nearly double Monel 400; retains ≥650 MPa at 482°C |
Yield Strength (0.2% Offset) | ≥760 | MPa | 3x higher than Monel 400’s ≥170 MPa; 482°C yield: ≥550 MPa |
Elongation (50mm Gauge Length) | ≥15 | % | Maintains ductility despite high strength; enables precision machining |
Density | 8.86 | g/cm³ | Slightly lower than Monel 400 (8.89 g/cm³) due to Al/Ti addition |
Melting Point | 1300-1350 | ℃ | Stable up to maximum service temperature (482°C) |
Magnetic Property | Non-magnetic | — | Suitable for navigation/electronic components |
Chemical Composition (Mass Fraction, Key Elements & Strengthening Mechanism)
Chemical Symbol | Composition Range (%) | Role in Performance |
Ni | 63.0-70.0 (Balance) | Stabilizes austenitic matrix; retains Monel 400’s corrosion resistance |
Cu | 27.0-33.0 | Enhances seawater/brine resistance; improves toughness |
Al | 2.3-3.1 | Core precipitation hardener; forms γ' phase (Ni₃Al) with Ti |
Ti | 0.35-0.85 | Synergizes with Al to refine γ' phase; boosts high-temp strength |
Fe | ≤2.0 | Improves hot workability; reduces hot cracking |
Mn | ≤1.5 | Refines grain size; enhances weldability |
C | ≤0.15 | Minimizes carbide precipitation; avoids intergranular corrosion |
S | ≤0.010 | Ultra-low content prevents sulfide stress cracking (SSC) in sour media |
Product Characteristics
1.Unmatched Strength-Corrosion Balance: Precipitation hardening delivers ≥965 MPa tensile strength (2x Monel 400) while retaining 95% of Monel 400’s marine corrosion resistance—outperforming most Ni-Cu and even some Incoloy alloys in high-stress corrosive environments;
2.Superior Marine & Acid Resistance: Ni-Cu matrix + low S content resists pitting, crevice corrosion, and SSC in seawater, brine, and dilute acids (e.g., 30% sulfuric acid, room temp)—meets NACE MR0175 for sour service;
3.Stable High-Temperature Performance: Retains high strength up to 482°C (60°C higher than Monel 400’s 427°C) with no brittle phase formation; suitable for medium-high temp load-bearing components;
4.Precision Processability: Despite high strength, it enables cold forming (annealed state) and precision machining; welding requires pre-heating (200-300°C) and post-weld aging to restore full strength;
5.Long-Term Structural Stability: γ' phase (Ni₃(Ti,Al)) is thermally stable—no strength degradation after 10,000 hours at 400°C; non-magnetic nature suits sensitive electronic/navigation applications.
Metallographic Structure
•Annealed State (Before Aging): Uniform face-centered cubic (FCC) austenitic matrix (ASTM grain size 5-8 grades) with Al/Ti dissolved in the Ni-Cu matrix—no visible precipitates, ensuring good formability;
•Aged State (After Hardening): Austenitic matrix dispersed with nano-scale γ' phase (Ni₃(Ti,Al)) (10-30 nm in size) at grain boundaries and within grains. These precipitates act as "dislocation barriers" to enhance strength, while the single-phase austenitic base retains corrosion resistance—no harmful intermetallic phases (e.g., sigma phase) form.
Product Forms and Executive Standards
Product Form | Main International Executive Standards | Application Reference |
Plates/Sheets | ASTM B127, EN 10088-2 | Deep-sea oil well pressure vessel liners, high-stress marine hull components |
Seamless Pipes/Tubes | ASTM B165, EN 10216-5 | Subsea oil & gas flowlines (high pressure), acid transport tubes (high stress) |
Bars/Forgings | ASTM B160, EN 10269 | Marine propeller shafts, pump impellers (high torque), valve stems (high pressure) |
Wires/Rods | ASTM B164, EN 10250-3 | Precision springs (corrosive environments), welding filler wires for high-strength joints |
Fasteners | ASTM F467, EN 10269 | Offshore platform high-strength bolts, subsea connector fasteners |
