Inconel Alloy 625/N06625/2.4856/NS 3306 Precipitation Hardenable for Enhanced Mechanical Properties in Severe Environments

Inconel Alloy 625/N06625/2.4856/NS 3306 Precipitation-Hardenable for Enhanced Mechanical Properties in Severe Environments

Inconel Alloy 625 (UNS N06625) is a high-performance, versatile alloy with outstanding properties in high-temperature and corrosive environments. Its exceptional resistance to oxidation, pitting, and stress corrosion cracking, along with its high strength and good fatigue resistance, make it a preferred choice for industries like aerospace, chemical processing, marine, nuclear, and oil and gas. The alloy’s combination of heat resistance, strength, and weldability ensures its reliability in the most demanding applications.

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Key Features:

• Composition:

Nickel (Ni): 58%–70% (balance of the alloy).

Chromium (Cr): 20%–23% (providing resistance to oxidation and corrosion).

Molybdenum (Mo): 8%–10% (adds resistance to pitting, crevice, and stress corrosion cracking).

Iron (Fe): 5%–10%.

Other elements include niobium (Nb), titanium (Ti), and small amounts of carbon, manganese, and silicon.

• Mechanical Properties:

Tensile Strength: Approx. 1,380–1,500 MPa (varies depending on the form and temperature).

Yield Strength: Approx. 690–800 MPa.

Elongation: Typically around 30% (providing good ductility).

Hardness: Good hardness properties, typically in the range of Rockwell B 90–95.

• Corrosion and Oxidation Resistance:

Excellent Resistance to a wide range of aggressive environments, including sea water, acidic solutions, and high-temperature gases.

Inconel 625 has superior resistance to pitting, crevice corrosion, and stress corrosion cracking, making it ideal for use in severe service conditions.

Performs well in oxidizing and reducing environments due to its high chromium and molybdenum content.

It is particularly resistant to high-temperature oxidation and to carburization, making it ideal for high-temperature applications in combustion and furnace environments.

• Thermal Properties:

Melting Point: Around 1,350°C–1,400°C (2,462°F–2,552°F).

Thermal Conductivity: Lower than pure metals like copper, but adequate for high-temperature applications.

Coefficient of Expansion: Moderate, making it stable under thermal cycling.

• Electrical and Magnetic Properties:

Electrical Conductivity: Relatively low compared to copper, typical for high-performance alloys.

Magnetic Permeability: Inconel 625 is non-magnetic, making it suitable for sensitive electronic or magnetic applications.

• Weldability and Fabrication:

Excellent Weldability: Inconel 625 has good weldability by most standard welding methods, including TIG, MIG, and plasma welding. It can be welded in both the annealed and solution-treated conditions.

Can be cold-formed and hot-formed, though hot forming must be done with caution to avoid excessive grain growth.

Machinability: Although it is a tough material, it can be machined, albeit with difficulty. It is generally recommended to use carbide tools for machining.

Applications:

• Aerospace: Used in turbine blades, seals, exhaust systems, and other high-temperature engine components due to its heat and corrosion resistance.
• Chemical Processing: Equipment exposed to high-temperature and corrosive chemicals, such as heat exchangers, reactors, and piping systems.
• Marine Environments: Due to its outstanding resistance to seawater corrosion, Inconel 625 is used in marine and offshore applications, such as subsea equipment, propeller blades, and other parts exposed to saltwater.
• Nuclear Power: Used in reactor cores, steam generator tubing, and other parts exposed to radiation and high temperatures.
• Oil and Gas: Ideal for high-performance applications like gas turbines, deep-sea equipment, and equipment exposed to extreme pressure and temperature conditions.
• Industrial Furnace: For parts like furnace linings, heating elements, and combustion chambers.