What's the difference between the Inconel X-750 and the Inconel 718?
What's the difference between the Inconel X-750 and the Inconel 718?
The main difference lies in their properties. Inconel 718 is a high-strength alloy primarily used in the aerospace industry due to its excellent high-temperature mechanical properties and good corrosion resistance. Inconel X-750, on the other hand, is better suited for applications requiring high creep rupture strength, oxidation resistance, and thermal fatigue resistance, such as in the power generation and chemical industries. Inconel 718 contains molybdenum, resulting in a more complex chemical composition that provides superior strength and corrosion resistance, while X-750 is strengthened by the addition of aluminum and titanium.
What Is Inconel 718?
Inconel 718 is a nickel-based superalloy known for its high strength, corrosion resistance, and excellent weldability. It is a precipitation-hardening alloy, meaning its mechanical properties can be enhanced through heat treatment.
Temperature Range: Performs well over a temperature range of -250°C to 700°C.
Corrosion Resistance: Exhibits excellent resistance to oxidation, pitting, and stress corrosion cracking, even in harsh environments.
Mechanical Strength: High tensile and yield strength due to the presence of niobium.
Applications: Commonly used in aerospace turbines, gas turbines, nuclear reactors, and oil and gas extraction.
What Is Inconel X-750?
Inconel X-750 is another nickel-based alloy that performs excellently at high temperatures. It also exhibits precipitation hardening properties, but compared to Inconel 718, it has a higher aluminum and titanium content, resulting in improved high-temperature strength.
Temperature Range: Performs best at temperatures up to 980°C.
Creep Resistance: Excellent resistance to deformation under long-term high-temperature stress.
Corrosion Resistance: Good resistance to oxidation and chemical corrosion, but slightly less than Inconel 718.
Applications: Commonly used in jet engines, nuclear reactors, springs, and fasteners.
Inconel 718 vs Inconel X-750: What Are Their Differences?
Inconel X750 Chemical Composition
| Grade | Ni | Cr | Al | C | Mn | Ti | Cu | Si | S |
| Inconel X-750 | 70.0 min | 14.0 - 17.0 | 0.40 - 1.0 | .08 max | 1.00 max | 2.25 - 2.75 | 0.50 max | .50 max | .01 max |
Inconel 718 Chemical Composition
| Grade | C | Mn | Si | Fe | S | Cr | Al | Ni | |
| 718 | min. | – | – | – | bal | – | 17.0 | 0.2 | 50.0 |
| max. | 0.08 | 0.35 | 0.35 | bal | 0.01 | 21.0 | 0.8 | 55.0 | |
Mechanical Properties: Inconel 718 vs Inconel X-750
| Property | Inconel 718 | Inconel X-750 |
|---|---|---|
| Tensile Strength | 1370 MPa | 1100 MPa |
| Yield Strength | 1030 MPa | 780 MPa |
| Elongation | 12-15% | 15-20% |
| Hardness (Rockwell) | B95-C36 | B88-C32 |
Physical Properties: Inconel 718 and Inconel X-750
| Property | Inconel 718 | Inconel X-750 |
|---|---|---|
| Density (g/cm³) | 8.19 | 8.28 |
| Melting Range (°C) | 1260 – 1336 | 1390 – 1430 |
| Thermal Conductivity (W/m·K, at 20°C) | ~11.4 | ~11.4 |
| Electrical Resistivity (µΩ·m, at 20°C) | ~1.29 | ~1.29 |
| Elastic Modulus (GPa) | 200–210 | 207 |
Main Standards and Specifications
Both Inconel 718 and Inconel X-750 comply with international standards to ensure quality and traceability:
Inconel 718
ASTM B637 (Bars, Forgings)
ASTM B670 (Plates, Sheets, Strips)
AMS 5662 / AMS 5663 (Aerospace Specifications)
ISO 15156 / NACE MR0175 (Oil & Gas Applications)
Inconel X-750
ASTM B637 (Bars, Forgings)
ASTM B670 (Plates, Sheets, Strips)
AMS 5667 / AMS 5668 (Aerospace & High-Temperature Applications)
MIL-N-6856 (Military Specifications)
Applications of Inconel 718 and Inconel X-750
Advantages of Inconel 718
Superior mechanical strength.
Better weldability.
Excellent resistance to pitting and stress-corrosion cracking.
Advantages of Inconel X-750
Better high-temperature performance.
Excellent creep resistance.
Ideal for long-term, high-heat exposure applications.
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/X-750 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/X-750 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/X-750, 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.
