What are the differences between Inconel 690 and 625 alloys?
What are the differences between Inconel 690 and 625 alloys?
The main differences lie in their chemical composition and intended use: Inconel 690 is a high-chromium alloy primarily used in applications such as nuclear reactors and steam generators due to its excellent corrosion resistance; while Inconel 625 is a versatile nickel-molybdenum alloy favored for its high strength, fatigue resistance, and corrosion resistance, and is widely used in fields such as ship components, aerospace components, and chemical processing equipment.
What is INCONEL 690?
INCONEL 690 alloy (UNS N06690/W. Nr. 2.4642) is a high-chromium nickel alloy with excellent resistance to various corrosive aqueous media and high-temperature performance. In addition to corrosion resistance, alloy 690 also possesses high strength, good metallurgical stability, and excellent machinability.
Inconel 625
Composition: High molybdenum content (approximately 9 wt%), molybdenum being the key element for its high strength and corrosion resistance.
Strengthening Mechanism: Primarily employs solid solution strengthening; molybdenum atoms induce strain in the nickel alloy lattice, thereby hindering dislocation movement.
Main Properties: Excellent tensile strength, fatigue strength, and corrosion resistance.
Main Applications: Marine components, aerospace components, and chemical equipment.
Inconel 690
Composition: Extremely high chromium content (up to 31%) and also high nickel content (at least 58%).
Strengthening Mechanism: Strength and corrosion resistance are achieved through its high chromium and high nickel content.
Main Properties: Excellent resistance to water corrosion, pitting corrosion, crevice corrosion, and high-temperature oxidation. Furthermore, it exhibits excellent resistance to stress cracking.
Main Applications: Nuclear reactor steam generators and other components used in corrosive chemical or aqueous environments.
| Feature | Inconel 625 | Inconel 690 |
|---|---|---|
| Primary Alloying Elements | Nickel, Chromium, Molybdenum, Niobium | Nickel, Chromium |
| Key Property | High strength, fatigue resistance, and general corrosion resistance | High resistance to aqueous corrosion and high-temperature oxidation |
| Common Applications | Marine components, aerospace, chemical processing, jet engines | Steam generators, nuclear reactors, water treatment systems, chemical processing |
| Strengthening Mechanism | Solid solution strengthening from molybdenum and niobium | Primarily relies on its high chromium and nickel content for corrosion resistance |
| Specific Resistance | Resistance to pitting and crevice corrosion, chloride stress corrosion | Resistance to stress-corrosion cracking, strong oxidizing media, and specific mixed acids like HNO₂-HF |
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅ Over 18 years of export experience, products sold to more than 80 countries
✅ Certified by ISO, SGS, and BV
✅ Global inventory of Inconel, Hastelloy, Incoloy, and Monel alloy tubing, plates, and bars
✅ Custom processing services available – including cutting, polishing, CNC machining, and packaging
✅ Fast delivery within 7-15 days, supported by global logistics partners
📦 Packaging and Shipping
All stainless steel products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel is a supplier of GH4169 alloy, offering a wide range of products including: seamless pipe (sizes: 4-219 mm; thickness: 0.5-20 mm); welded pipe (sizes: 5.0-1219.2 mm; thickness: 0.5-20 mm); plates (thickness: 0.1 to 100 mm; width: 10-2500 mm); strips; alloy round bars (diameter: 3-800 mm); flat bars (thickness: 2-100 mm; width: 10-500 mm); hexagonal bars (size: 2-100 mm); wire rods; and extruded profiles. We collaborate with steel mills to provide our customers with GH4169 alloy products that meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells GH4169, pipes, plates, strips, round bars, flat bars, forged billets, hexagonal steel, wire rods, and extruded profiles. Please feel free to contact us at ss@gneesteel.com for a quote.
