What are the differences between Inconel 625 and SS 316 alloys?
What are the differences between Inconel 625 and SS 316 alloys?
Inconel 625 is a nickel-based alloy with excellent strength, toughness, and high-temperature performance, while SS 316 is a stainless steel alloy that is more affordable and easier to process. The main difference is that Inconel 625 can withstand extreme high temperatures and corrosive environments, but its initial cost is higher and it is more difficult to process. SS 316 is more suitable for applications that require good corrosion resistance but cannot withstand the extreme temperatures or stresses achievable with Inconel 625.
Can Inconel 625 be hardened?
Hardening treatment helps improve the strength and hardness of the material. The precipitation hardening temperature of Inconel 625 is typically between 540°C and 620°C, with a holding time of approximately eight hours.
Chemical Composition Comparison
Inconel 625 Alloy Main Elements and Their Contents
Ni (Ni): 58-60%. Nickel forms the main matrix, contributing to improved strength and corrosion resistance.
Chromium (Cr): 20-23%. Chromium enhances oxidation resistance.
Molybdenum (Mo): 8-10%. Molybdenum significantly improves resistance to pitting and crevice corrosion, especially in chloride environments.
Niobium (Nb): 3.15-4.15%. Niobium stabilizes the alloy and prevents sensitization, which leads to intergranular corrosion.
Iron (Fe): ≤5%. Iron content is kept at a low level to maintain the required properties.
Carbon (C): ≤0.10%. Low carbon content minimizes carbide precipitation, thus preserving mechanical properties.
Other elements: Small amounts of cobalt (Co), manganese (Mn), and silicon (Si), all below 1%.
316 Stainless Steel (SS 316) Main Elements and Their Contents
Iron (Fe): 65-70%. Iron forms the basic structure of the alloy.
Chromium (Cr): 16-18%. Chromium is crucial for corrosion resistance; it forms a passivating oxide layer on the surface.
Nickel (Ni): 10-14%. Nickel stabilizes the austenitic structure and enhances corrosion resistance.
Molybdenum (Mo): 2-3%. Molybdenum improves resistance to pitting and crevice corrosion caused by chlorides.
Carbon (C): ≤0.08%. Low carbon content minimizes the risk of sensitization and intergranular corrosion.
Other elements: Manganese (Mn) ≤2% and Silicon (Si) ≤1% improve deoxidation properties.
Inconel 625 vs. SS316: Corrosion Resistance
Both Inconel 625 and SS316 exhibit excellent corrosion resistance, but there are some key differences between them. Because Inconel 625 contains higher levels of molybdenum and niobium, its resistance to pitting and crevice corrosion is superior to SS316. This means it can withstand harsher environments than SS316 without any damage or performance degradation.
In terms of general corrosion resistance, the two alloys perform similarly in milder environments such as food processing equipment or chemical plants. However, if you need an alloy that can withstand more demanding conditions, such as high temperatures or seawater environments, Inconel 625 is a better choice due to its superior resistance to pitting and crevice corrosion.
Inconel 625 vs. SS316: Strength
Both alloys are known for their excellent strength, but there are some differences in this aspect. Inconel 625 has a higher yield strength than SS316 (65 ksi vs. 45 ksi), making it more suitable for applications where the material needs to withstand frequent cyclic loading or deform due to dynamic forces such as vibration and pressure fluctuations. Furthermore, Inconel 625 also has better fatigue strength than SS316, making it more suitable for applications involving rotating components (such as shafts or gears) and aerospace components subjected to extreme temperatures.
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 Inconel 625 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 Inconel 625 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 Inconel 625, 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.
