Inconel X-750 UNS N07750

Introduction to Inconel X-750

Inconel X-750 is a high-strength, nickel-chromium-based superalloy known for its excellent mechanical properties, corrosion resistance, and ability to perform under extreme temperatures. Developed by the International Nickel Company (INCO), Inconel X-750 has become a critical material in industries such as aerospace, nuclear engineering, gas turbines, and chemical processing. Its unique combination of strength, oxidation resistance, and thermal stability makes it suitable for demanding applications.

Composition and Properties

Inconel X-750 is primarily composed of nickel (approximately 70%), chromium (14-17%), and iron (5-9%). It also contains significant amounts of niobium (0.7-1.2%) and titanium (2.25-2.75%), which contribute to its precipitation-hardening capabilities. Small additions of aluminum (0.4-1.0%) and carbon (0.08% max) further enhance its strength and high-temperature performance.

The alloy exhibits excellent tensile strength, creep resistance, and fatigue resistance at temperatures up to 700°C (1292°F). It also maintains good oxidation resistance and corrosion resistance in both aqueous and high-temperature environments. These properties make Inconel X-750 particularly suitable for applications requiring long-term stability under stress and heat.

Heat Treatment and Fabrication

Inconel X-750 is a precipitation-hardening alloy, meaning its mechanical properties can be significantly enhanced through heat treatment. The standard heat treatment process involves:

1. Solution Annealing: Heating the alloy to 1150-1175°C (2100-2150°F) followed by rapid cooling.

2. Aging: Heating to 705-760°C (1300-1400°F) for 16-20 hours to precipitate gamma prime (γ') phases, which strengthen the material.

Fabrication of Inconel X-750 can be challenging due to its high strength and work-hardening rate. However, it can be machined, welded, and formed using appropriate techniques. Welding requires careful control of heat input to avoid cracking and to maintain the alloy's corrosion resistance.

Applications

Inconel X-750 is widely used in industries that demand high performance under extreme conditions. Key applications include:

• Aerospace: Jet engine components, such as turbine blades, seals, and afterburner parts, due to its high-temperature strength and oxidation resistance.

• Nuclear Engineering: Reactor core components, fuel assembly parts, and control rod mechanisms, where its radiation resistance and thermal stability are critical.

• Gas Turbines: Combustion chambers, turbine discs, and bolts, where it withstands high stresses and temperatures.

• Chemical Processing: Heat exchangers, valves, and fasteners, where it resists corrosion in aggressive environments.

• Industrial Gas Turbines: Components exposed to high temperatures and mechanical stress.

Advantages of Inconel X-750

• High strength and toughness at elevated temperatures.

• Excellent oxidation and corrosion resistance.

• Good creep and fatigue resistance.

• Suitable for long-term use in extreme environments.

Conclusion

Inconel X-750 is a versatile and reliable superalloy that has proven indispensable in high-performance applications across various industries. Its unique combination of mechanical properties, corrosion resistance, and thermal stability ensures its continued use in some of the most demanding environments. As technology advances and the need for materials that can withstand extreme conditions grows, Inconel X-750 will remain a critical material in engineering and manufacturing.

Chemistry

Tensile Data

D- Forging quality is furnished to chemical requirements and surface inspection only. No mechanical properties required.

Specifications

Machining

Machinability Ratings