What is the difference between Inconel 625 and Inconel 718?
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What is the difference between Inconel 625 and Inconel 718?
The main difference between Inconel 625 and 718 alloys lies in their chemical composition. Both are nickel alloys, but they differ in the amounts of various chemical substances they contain, thus distinguishing them. Alloy 625 is primarily composed of nickel, while alloy 718 is primarily composed of nickel-cobalt (Ni+Co).
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What are the advantages of Inconel 718?
Inconel 718 is a high-strength, corrosion-resistant nickel-based superalloy. It possesses excellent mechanical properties, high-temperature strength, and resistance to oxidation and corrosion.
Composition: The main difference between Inconel Alloy 625 and 718 lies in their chemical composition. Both are nickel alloys, but they contain different proportions of various chemical substances that differentiate them.
Alloy 625 is primarily nickel-based, while Alloy 718 is nickel-cobalt (Ni+Co)-based. The use of nickel-cobalt in Alloy 718 gives it higher hardness and strength. On the other hand, Alloy 625 contains a higher proportion of chromium and molybdenum, thus providing greater corrosion resistance. See below for a complete comparison of the chemical compositions of Inconel 625 and 718.
| Element | Inconel 625 | Inconel 718 |
|---|---|---|
| Chromium (Cr) | 22 | 17-21 |
| Iron (Fe) | 4 | Balance |
| Titanium (Ti) | 0.3 | 0.65-1.15 |
| Aluminum (Al) | 0.3 | 0.20-0.80 |
| Carbon (C ) | 0.05 | 0.08 max |
| Phosphorous (P) | 0.01 | 0.015max |
| Boron (B) | - | 0.006 max |
| Nickel (Ni) | 60 | 50-55 |
| Molybdenum (Mo) | 9 | 2.80-3.30 |
| Niobium (Nb) | 3.5 | 4.75-5.50 |
| Manganese (Mn) | 0.3 | 0.35 max |
| Silicon (Si) | 0.25 | 0.35 max |
| Sulfur (S) | 0.003 | 0.015 max |
| Cobalt (Co) | - | 1.00 max |
| Tantalum (Ta) | - | 0.30 max |
Mechanical Properties of Inco 718 & 625
| Properties | Inconel 625 | Inconel 718 |
|---|---|---|
| Elongation at Break | 33 to 34 % | 12 to 50 % |
| Poisson's Ratio | 0.29 | 0.29 |
| Shear Strength | 530 to 600 MPa (77 to 87x 103psi) | 660 to 950 MPa (96 to 140x 103psi) |
| Yield Strength | 320 to 450 MPa (47 to 65x 103 psi) | 510 to 1330 MPa (74 to 190 x 103 psi) |
| Elastic Modulus | 190 GPa (28 x 106 psi) | 200 GPa (30 x 106 psi) |
| Fatigue Strength | 240 to 320 MPa (34 to 47 x 103 psi) | 460 to 760 MPa (67 to 110 x 103 psi) |
| Shear Modulus | 530 to 600 MPa (77 to 87 x 103 psi) | 75 GPa (11 x 106 psi) |
| Tensile Strength | 790 to 910 MPa (120 to 130 x 103 psi) | 930 to 1530 MPa (130 to 220 x 103 psi) |
Application
Inconel 625 and Inconel 718 are suitable for a wide range of industries and applications. However, their respective compositions and properties make each alloy stand out in specific areas.
Inconel 625 Applications
Due to its excellent corrosion resistance, Inconel 625 alloy is most commonly used in the oil and gas industry. This makes it the alloy of choice for subsea equipment. It is also used in the corrosive environments of the aerospace industry, such as exhaust systems, furnaces, and engine thrust reversers.
Inconel 718 Applications
Inconel 718 is a mainstay material in the aerospace industry. Its exceptional heat resistance makes it ideal for high-temperature applications, including engine components. It is also used in high-performance automotive engines in the motorsport industry.
Product Forms
Both alloys 625 and 718 are easy to form and weld, so they are readily available in a variety of product forms.
Inconel 625 Product Forms
Pipe
Coil
Welding Wire
Sheet and Plate
Round Bar
Pipe Fittings
Flanges
Inconel 718 Product Forms
Round Bar
Sheet and Plate
Welding Wire
Why Choose Gnee Nickel Alloy (Supplier Example)?
✅ Large stock of Inconel alloy tubes/bars/plates/fittings/coils, fast shipping.
✅ Factory direct sales, highly competitive prices, excellent value for money.
✅ Comprehensive quality assurance: Material Testing Certificate (MTC), chemical composition certificate, and mechanical property certificate.
✅ Value-added services: slitting, cutting, polishing, surface treatment.
✅ Worldwide shipping, secure and reliable packaging, and provision of export-required documents.
Email: ss@gneemetal.com
Gnee Steel is a supplier of Inconel 718/625 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 718/625 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 718/625, 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.
