Inconel 718 vs Inconel X-750 Disc Springs: Material Selection for High-Temperature Preload

Why the comparison matters

Many buyers search for Inconel springs or nickel alloy Belleville washers after ordinary spring steel has become too risky. At that point, the material choice affects not only maximum strength but also relaxation behavior, fatigue margin, corrosion confidence and commercial availability.

Inconel 718 and X-750 can both be valid, but the correct review starts from the application instead of the alloy name.

Where Inconel 718 is commonly reviewed

Inconel 718 is often considered for HPHT valve systems, aerospace hardware, offshore tools and severe-service preload assemblies where strength and retained load are both important.

It is usually worth reviewing when failure consequence is high and the buyer needs stronger confidence in load retention under demanding temperature and mechanical stress.

• HPHT valve and actuator preload systems.
• Offshore and petrochemical equipment.
• Aerospace and high-strength industrial hardware.
• Applications needing documentation and engineering review.

Where Inconel X-750 is commonly reviewed

Inconel X-750 has a long history in high-temperature spring applications and is often reviewed where retained load, heat exposure and spring behavior are the main concerns.

For many industrial Belleville washer programs, X-750 can be a strong candidate when the application needs nickel alloy temperature performance but does not automatically require the same strength path as 718.

RFQ data that decides the material direction

The useful comparison needs normal and peak temperature, hold time under load, target force, working deflection, corrosion media, cycle duty, stack height and whether the spring works in a valve, flange, actuator or custom preload assembly.

With these inputs, FeTech can review whether Inconel 718, Inconel X-750, Inconel 625, Nimonic 90 or another alloy is the stronger technical and commercial fit.