Inconel625

1. Introduction to Inconel625 Material

Inconel625 alloy is solid-solution strengthened nickel-based wrought superalloy, with molybdenum and niobium as main strengthening elements. It features outstanding corrosion and oxidation resistance, stable tensile and fatigue performance from cryogenic temperature up to 980℃, and excellent resistance to stress corrosion under salt spray atmosphere. It resists various corrosive media in both oxidizing and reducing environments, with superior resistance to pitting, crevice, intergranular corrosion and chloride-induced corrosion.

2. Chemical composition of Inconel625

3. Physical performance of Inconel625

4. Features of Inconel625

• Excellent resistance to all kinds of corrosive media in oxidizing and reducing environments
• Superior pitting & crevice corrosion resistance, free from chloride-induced stress corrosion cracking
• Great resistance to inorganic acids including nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid and mixed acid solutions
• Stable anti-corrosion performance against various mixed inorganic acid solutions
• Good corrosion resistance to hydrochloric acid of all concentrations at 40℃
• Excellent machinability and weldability, no post-weld cracking susceptibility
• Certified for pressure vessel service at wall temperatures ranging from -196℃ to 450℃
• Complies with NACE MR-01-75 Grade VII standard for sour gas service

5. Inconel625 Metallographic structure

Inconel 625 has face-centered cubic lattice structure. After long-term aging at around 650℃, carbide particles and unstable quaternary phases precipitate and transform into stable orthorhombic Ni3(Nb,Ti) phases. Molybdenum and niobium dissolved in nickel-chromium matrix improve mechanical strength while slightly reducing ductility after solid solution strengthening.

6. Inconel625 corrosion resistance

Inconel 625 delivers outstanding corrosion resistance in most media. It resists pitting, crevice, intergranular and erosion corrosion under chloride conditions. It withstands inorganic acids (nitric, phosphoric, sulfuric, hydrochloric), alkalis and organic acids in both oxidizing and reducing environments, and effectively prevents chloride-induced stress corrosion cracking. It suffers negligible corrosion in seawater and industrial gas environments even at elevated temperatures. No welding embrittlement; resistant to carburization, oxidation and chlorine-containing gas corrosion under static or circulating service conditions.

7. Inconel625 Application Field

Soft annealed low-carbon Inconel625 is widely used in chemical processing industries; its high strength and corrosion resistance enable thinner lightweight structural parts. It is suitable for seawater contact components bearing high mechanical loads. Typical applications:

• Organic chemical equipment with chloride media, especially units using acid chloride catalysts
• Pulp & paper industry digesters and bleaching tanks
• Flue gas desulfurization system: absorption towers, reheaters, inlet baffles, wet fans, agitators, deflectors and flue ducts
• Sour gas production equipment and components
• Acetic acid & acetic anhydride reactors
• Sulfuric acid condensation equipment

High-temperature corrosion resistant service components across general industrial sectors. Inconel625 series are graded according to service environment requirements:

• Glass anti-corrosion series products
• High-precision castings: blades, turbochargers, turbine rotors, guide vanes, instrument connectors
• Centrifuges, high-temperature shafts and fittings for glass wool production; cobalt alloy heat-resistant support pads & slide rails for billet furnaces
• Valve seat rings
• Cast U-shaped resistance strips
• Centrifugal casting pipe series
• Nano-material series
• Low-density high-temperature structural alloys
• Functional alloys: expansion alloys, high-temperature high-elastic alloys, constant modulus elastic alloys
• Biomedical alloy products
• Electronic engineering sputtering target materials