What is the difference between Inconel X750 and 718 springs?

nconel X750 and Inconel 718 are both nickel-based superalloys, but they have different compositions and properties that make them suitable for different applications. Here’s a comparison of the two, particularly in the context of spring materials:

1. Composition:
Inconel 718: Contains nickel (50-55%), chromium (17-21%), iron (up to 19%), molybdenum (2.8-3.3%), and niobium (4.75-5.5%). It also has small amounts of other elements like titanium and aluminum.
Inconel X750: Contains nickel (70-75%), chromium (14-17%), iron (5-9%), and significant amounts of titanium (1-2.5%) and aluminum (0.2-0.6%). It is primarily used in high-temperature applications.
2. Mechanical Properties:
Inconel 718: Known for its high strength, excellent fatigue resistance, and good ductility, particularly at elevated temperatures. It can be heat-treated to enhance its properties.
Inconel X750: Offers high strength and oxidation resistance at elevated temperatures, but it has lower ductility compared to Inconel 718. It is often used in applications that require stability under high-temperature conditions.
3. Corrosion Resistance:
Inconel 718: Excellent corrosion resistance, particularly in acidic and saline environments, making it suitable for aerospace and oil and gas applications.
Inconel X750: Also offers good corrosion resistance but is more focused on high-temperature oxidation resistance rather than resistance to acidic environments.
4. Applications:
Inconel 718: Commonly used in aerospace components, gas turbines, and springs that operate in high-stress and corrosive environments.
Inconel X750: Primarily used in gas turbine engines, nuclear reactors, and other high-temperature applications where stability and strength are critical.
5. Heat Treatment:
Inconel 718: Can be age-hardened to improve strength and hardness through specific heat treatment processes.
Inconel X750: Typically used in the solution-annealed condition; aging is less common as it is designed for stability rather than hardening.

Chemical Properties of Inconel 718