INCONEL 718 is typically a better choice than INCONEL 625 when higher mechanical strength and fatigue resistance are required, especially at elevated temperatures.

Key differences:

  • Strength: INCONEL 718 is precipitation-hardened, giving it significantly higher yield and tensile strength than INCONEL 625.
  • Fatigue & creep resistance: 718 performs better under cyclic loading and long-term stress at high temperatures.
  • Structural applications: 718 is often preferred for load-bearing components, including turbine parts, fasteners, and engine hardware.
  • Temperature range: Both alloys perform well at high temperatures, but 718 is commonly specified where strength must be retained up to approximately 1300°F (704°C).

By contrast, INCONEL 625 is often selected for superior corrosion resistance and fabricability in chemically aggressive environments where extreme mechanical strength is less critical.

In short:

  • Choose INCONEL 718 for strength-driven, high-stress applications
  • Choose INCONEL 625 for corrosion-driven applications with moderate mechanical demands