The differences between Inconel alloy 601 and alloys 600, 617, 625, and 718.
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The differences between Inconel alloy 601 and alloys 600, 617, 625, and 718.
Inconel 601 possesses superior oxidation resistance (due to its aluminum content), differentiating it from Inconel 600 (a general-purpose high-temperature alloy), 617 (a high-temperature strength alloy containing cobalt/molybdenum), 625 (a corrosion-resistant/high-strength alloy containing molybdenum/niobium), and 718 (which achieves exceptional strength through precipitation hardening and is an ideal material for aerospace applications). Each alloy balances strength, corrosion resistance, and high-temperature performance in specific extreme environments, with 601 excelling in carburization resistance, while 718 offers the highest strength for structural applications.
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What are the differences between Inconel 617 and 601?
INCONEL 601 exhibits excellent oxidation resistance and strong resistance to chloride stress corrosion cracking and alkaline corrosion. In contrast, INCONEL 617 possesses superior metallurgical stability, strength, and oxidation resistance, performing particularly well in high-temperature environments.
Inconel 600/UNS N06600
Inconel 600 is a solid-solution strengthened alloy primarily composed of nickel and chromium. It exhibits excellent oxidation and corrosion resistance, making it suitable for chemical processing, aerospace, and nuclear engineering applications. The alloy's versatility allows it to withstand various corrosive environments and high-temperature conditions.
Inconel 601/UNS N06601
Inconel 601 builds upon Inconel 600 by enhancing oxidation resistance through the addition of aluminum. This modification forms a protective oxide layer, enabling the alloy to perform exceptionally well in high-temperature environments. Common applications include heat treatment equipment, heat treatment baskets, and components in pollution control systems.
Inconel 617/UNS N06617
Inconel 617 combines nickel, chromium, cobalt, and molybdenum, offering an exceptional balance of strength and oxidation resistance at high temperatures. Its high-temperature strength and corrosion resistance make it ideal for gas turbines, petrochemical processing, and heat exchangers.
Inconel 625/UNS N06625
Inconel 625 is renowned for its exceptional fatigue strength and thermal fatigue strength, possessing excellent oxidation and corrosion resistance. This alloy is widely used in the aerospace, marine, and chemical processing industries, particularly in applications requiring high strength and resistance to corrosive environments.
Inconel 718/UNS N07718
Inconel 718 is a precipitation-hardened nickel-chromium alloy containing significant amounts of iron, niobium, and molybdenum, along with smaller amounts of aluminum and titanium. It combines corrosion resistance with high strength and excellent weldability, including resistance to post-weld cracking. The alloy exhibits superior creep rupture strength at temperatures up to 1300°F (700°C), making it suitable for gas turbines, rocket engines, and nuclear reactors.
Chemical Composition (wt%) of Inconel Alloy
| Alloy | Ni | Cr | Fe | Mo | Co | Nb | Al | Ti | Mn | Si | C | Other |
| Inconel 600 | ≥72 | 14-17 | 6-10 | – | – | – | – | – | ≤1 | ≤0.5 | ≤0.15 | Cu ≤0.5, S ≤0.015 |
| Inconel 601 | 58-63 | 21-25 | Balance | – | – | – | 1.0-1.7 | – | ≤1 | ≤0.5 | ≤0.10 | S ≤0.015 |
| Inconel 617 | ≥44.5 | 20-24 | ≤3 | 8-10 | 10-15 | – | 0.8-1.5 | – | ≤0.5 | ≤0.5 | 0.05-0.15 | B ≤0.006, S ≤0.015 |
| Inconel 625 | ≥58 | 20-23 | ≤5 | 8-10 | ≤1 | 3.15-4.15 | ≤0.4 | ≤0.4 | ≤0.5 | ≤0.5 | ≤0.10 | P ≤0.015 |
| Inconel 718 | 50-55 | 17-21 | Balance | 2.8-3.3 | ≤1 | 4.75-5.5 | 0.2-0.8 | 0.65-1.15 | ≤0.35 | ≤0.35 | ≤0.08 | B ≤0.006, Cu ≤0.3 |
Mechanical Properties (Annealed Condition) of Inconel Alloy
| Alloy | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (Rockwell) |
| Inconel 600 | 550 (80 ksi) | 240 (35 ksi) | 30% | B80 |
| Inconel 601 | 550 (80 ksi) | 205 (30 ksi) | 30% | B88 |
| Inconel 617 | 750 (109 ksi) | 345 (50 ksi) | 35% | B95 |
| Inconel 625 | 760 (110 ksi) | 345 (50 ksi) | 30% | B95 |
| Inconel 718 | 1240 (180 ksi) | 1035 (150 ksi) | 12% | C35 |
Product Forms and ASTM Standards
| Alloy | Pipes & Tubes | Plates, Sheets & Strips | Bars & Rods | Forgings | Rings |
| Inconel 600 | ASTM B167 | ASTM B168 | ASTM B166 | ASTM B564 | Custom |
| Inconel 601 | ASTM B167 | ASTM B168 | ASTM B166 | ASTM B564 | Custom |
| Inconel 617 | ASTM B166 | ASTM B168 | ASTM B166 | ASTM B564 | Custom |
| Inconel 625 | ASTM B444, B705 | ASTM B443 | ASTM B446 | ASTM B564 | Custom |
| Inconel 718 | ASTM B983 | ASTM B670 | ASTM B637 | ASTM B637 | AMS 5662 |
Heat Treatment Process of Inconel Alloy
| Alloy | Solution Annealing Temperature | Cooling Method | Precipitation Hardening (if applicable) |
| Inconel 600 | 1010–1150°C (1850–2100°F) | Air cool | Not applicable |
| Inconel 601 | 1065–1180°C (1950–2150°F) | Air cool | Not applicable |
| Inconel 617 | 1120–1205°C (2050–2200°F) | Air cool | Not applicable |
| Inconel 625 | 980–1040°C (1800–1900°F) | Water quench | Not applicable |
| Inconel 718 | 980°C (1800°F) for 1 hr, then 720°C (1325°F) for 8 hrs | Air cool | Yes - age-hardened for high-strength |
Weldability of Inconel Alloy
| Alloy | Weldability Rating | Recommended Welding Process | Post-Weld Heat Treatment |
| Inconel 600 | Excellent | GTAW (TIG), GMAW (MIG), SMAW (Stick) | Not required |
| Inconel 601 | Good | GTAW, GMAW, SMAW | Not required |
| Inconel 617 | Good | GTAW, GMAW | Not required |
| Inconel 625 | Excellent | GTAW, GMAW, SMAW, PAW (Plasma) | Not required |
| Inconel 718 | Moderate (susceptible to cracking) | GTAW, Electron Beam, Laser | Solution annealing is recommended after welding |
Welding precautions:
Inconel 625 and 718 alloys have excellent welding properties and a very low tendency to crack.
Because Inconel 718 has a precipitation-hardened structure, precise control of welding temperature is required to avoid the formation of microcracks.
Corrosion Resistance Comparison
| Alloy | Oxidation Resistance | Sulfidation Resistance | Acid Resistance | Seawater Resistance |
| Inconel 600 | Excellent up to 1095°C (2000°F) | Moderate | Good (Nitric, Hydrochloric acids) | Moderate |
| Inconel 601 | Outstanding up to 1250°C (2280°F) | Excellent | Limited (resists some acids) | Limited |
| Inconel 617 | Outstanding up to 1100°C (2000°F) | Excellent | Moderate | Limited |
| Inconel 625 | Excellent up to 980°C (1800°F) | Good | Excellent (resists most acids) | Excellent |
| Inconel 718 | Good up to 650°C (1200°F) | Good | Good | Moderate |
Corrosion Resistance Highlights:
Due to its molybdenum content, Inconel 625 performs exceptionally well in marine environments, exhibiting excellent resistance to pitting and crevice corrosion.
Inconel 601 forms a tightly adhering oxide layer, making it ideal for high-temperature oxidizing environments.
Inconel 718 sacrifices some corrosion resistance in exchange for higher strength and creep resistance, making it particularly suitable for high-stress aerospace applications.
Industry-Specific Applications
| Alloy | Aerospace | Oil & Gas | Chemical Processing | Marine & Offshore | Power Generation |
| Inconel 600 | Jet engine components, exhaust liners | Furnace components, heat exchangers | Caustic alkali environments | Not ideal (limited seawater resistance) | Steam superheaters, nuclear reactor components |
| Inconel 601 | Afterburners, combustion cans | Reformer tubes, flare stacks | High-temp sulfur-bearing atmospheres | Not ideal | Gas turbines, heat treating equipment |
| Inconel 617 | Gas turbines, combustion liners | High-temp piping, flue gas systems | High-temperature chemical processing | Limited use | Heat exchangers, petrochemical plants |
| Inconel 625 | Rocket engine thrust chambers, heat shields | Sour gas pipelines, offshore platforms | Acid-resistant piping, scrubbers | Propeller blades, seawater components | Nuclear reactors, waste heat boilers |
| Inconel 718 | Turbine discs, jet engines, space shuttle components | Downhole tools, casing hangers | Acidic environments needing high-strength | Limited use | Gas turbines, cryogenic tanks |
Key takeaways:
Inconel 625 performs exceptionally well in marine and chemical environments due to its superior corrosion resistance.
Inconel 718 dominates the aerospace industry with its high strength and creep resistance, but its performance is overkill in highly corrosive environments.
Inconel 601 offers unparalleled advantages in extreme high-temperature environments such as furnaces and gas turbines.
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
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📦 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 601 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 601 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 601, 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.
