Inconel 600 and Inconel 625 are nickel-based superalloys engineered for extreme temperature, corrosion, and mechanical loading conditions. They are widely used in aerospace, chemical processing, marine, nuclear, and oil & gas industries where failure is not an option.
Alloy Overview
Inconel 600 is a nickel–chromium alloy offering excellent oxidation resistance and stability at high temperatures.
Inconel 625 is a nickel–chromium–molybdenum alloy strengthened by molybdenum and niobium, providing exceptional strength, fatigue resistance, and corrosion performance.
Strengthening & Metallurgical Behavior
Inconel 600
• Solid-solution strengthened (Ni-Cr-Fe)
• Single-phase FCC structure
• No precipitation hardening
• Strength increases through cold working
Inconel 625
• Solid-solution strengthening from molybdenum
• Precipitation strengthening via Nb-rich γ″ phase
• Excellent microstructural stability
• Superior creep and fatigue resistance
Corrosion & Oxidation Resistance
Inconel 600
Excellent resistance to high-temperature oxidation, carburization,
nitriding, chloride stress-corrosion cracking, and dry chlorine or ammonia.
Inconel 625
Outstanding resistance to pitting and crevice corrosion, seawater,
marine atmospheres, chloride-induced SCC, and acidic or reducing environments.
Refining & Processing Properties
Melting & Refining
Vacuum Induction Melting (VIM) and Vacuum Arc Remelting (VAR)
for high cleanliness and reliability.
Fabrication
Good hot and cold workability, excellent weldability without post-weld
heat treatment, and the ability to form complex shapes.
Machining is difficult due to rapid work hardening.
Available Forms
Sheets & plates
Bars & rods
Pipes & tubes
Wire
Forgings
Fasteners
Applications
Inconel 600
Furnace components
Heat-treatment fixtures
Nuclear reactor parts
Chemical processing equipment
Thermocouple sheaths
Inconel 625
Offshore and subsea equipment
Aerospace engine components
Chemical reactors and heat exchangers
Marine and nuclear piping
Oil & gas downhole components
Advantages
Inconel 600
✔ Excellent oxidation resistance
✔ Stable at high temperatures
✔ Good corrosion resistance
✔ Easier fabrication than stronger superalloys
Inconel 625
✔ Extremely high strength
✔ Outstanding corrosion and fatigue resistance
✔ Excellent weldability
✔ Superior marine and chemical performance
Limitations
❌ High material and fabrication cost
❌ Low thermal conductivity
❌ Difficult machining
❌ Over-specification for mild environments
Why Choose Inconel 600 or 625?
Choose Inconel 600 when oxidation resistance and thermal stability are critical and moderate strength is sufficient.
Choose Inconel 625 when severe corrosion and high mechanical loading coexist, especially in marine, offshore, and chemical environments.
Inconel 600 is a robust heat- and corrosion-resistant alloy, while Inconel 625 is a high-strength superalloy engineered for the harshest service conditions.