Inconel X-750 Powder Metallurgy Steam Gas Turbine Disc
Introduction
Inconel X-750 powder metallurgy is an ideal solution for manufacturing steam and gas turbine discs operating in aggressive, high-temperature, and high-pressure environments. At Neway AeroTech, we use advanced powder metallurgy turbine disc techniques to consolidate Inconel X-750 into fully dense, fine-grained components with exceptional creep strength, oxidation resistance, and dimensional stability. These discs are deployed in power generation, nuclear systems, and industrial gas turbines, where extended life under cyclical thermal and mechanical stress is critical.
Powder metallurgy ensures consistent properties throughout large cross-section parts, while enabling complex profiles and tight tolerance control required for rotor assemblies.
Core Technology of Inconel X-750 PM Turbine Discs
Powder Production: Spherical Inconel X-750 powders (10–80 µm) produced by gas atomization for uniform chemistry and flow characteristics.
Hot Isostatic Pressing (HIP): Powders consolidated under 1150–1200°C and 100–150 MPa, achieving >99.9% density and eliminating internal porosity.
Optional Isothermal Forging: For large discs, forging at ~1100°C further refines grain structure and enhances axial strength under rotational loads.
Solution and Aging Treatment: Heat treatment (solution at ~1150°C, aging at 730°C) optimizes γ′ phase precipitation and stabilizes mechanical performance.
CNC Machining and Balancing: Multi-axis CNC machining delivers ±0.01 mm tolerance on all rotor-critical geometries.
Inspection and Certification: Non-destructive and dimensional testing, including X-ray inspection and CMM validation, ensure compliance with turbine OEM specifications.
Material Characteristics of Inconel X-750 PM Discs
Property | Value |
|---|---|
Max Operating Temp | 700–750°C |
Ultimate Tensile Strength | 950–1100 MPa |
Yield Strength | ≥800 MPa |
Creep Resistance | Excellent at sustained load and temp |
Oxidation Resistance | High in steam and hot gas environments |
Density (Post-HIP) | >99.9% |
Dimensional Accuracy | ±0.01 mm (machined) |
Case Study: Inconel X-750 Disc for Combined Cycle Power Turbine
Project Background
A combined cycle gas-steam power plant required a turbine disc for a crossover application between steam and exhaust gas flow, operating at 700°C with high-cycle fatigue conditions. The client selected Inconel X-750 due to its excellent thermal stability and PM suitability for large disc geometry.
Typical Applications of Inconel X-750 Turbine Discs
Steam Turbine HP/LP Rotors (X-750): Used in base-load thermal plants, resisting oxidation and creep at continuous high-pressure steam exposure.
Exhaust Stage Gas Turbine Discs: Positioned at hot section exits in industrial turbines where mechanical load and thermal gradients converge.
Nuclear Circulator Turbine Discs: Operate in helium or steam environments with high neutron exposure, requiring structural stability and radiation tolerance.
Combined Cycle Power Turbine Interface Discs: Inconel X-750 used where steam and gas expansion overlap, managing pressure gradients and fluctuating load.
Manufacturing Workflow
Powder Preparation: Inconel X-750 alloy atomized and classified for controlled particle size and composition uniformity.
HIP Consolidation: Billet consolidated at 1180°C and 150 MPa under vacuum, producing full-density turbine disc blanks.
Isothermal Forging (Optional): Large-diameter discs forged to refine grain structure and improve mechanical isotropy.
Heat Treatment: Two-stage aging performed after solutioning to develop γ′ phase structure and enhance creep-fatigue synergy.
Machining and Finishing: All bearing surfaces, bolt circles, dovetail fits, and bore tolerances machined to ±0.01 mm.
Non-Destructive Testing: Radiographic and ultrasonic scans ensure no internal defects; outer profiles verified via CMM inspection.
Balancing and Assembly Fitment: Rotor-balanced to ISO G1.0 for high-speed operation; pilot fits validated for mating with turbine shaft and casing.
Results and Validation
Mechanical Strength: Tensile strength >1050 MPa and YS >850 MPa confirmed at 700°C, meeting OEM turbine standards.
Thermal Stability: Less than 0.3% deformation after 1000-hour thermal soak at 750°C with repeated load cycling.
Fatigue and Creep Testing: Passed >30,000 low-cycle fatigue repetitions at elevated temperature with no crack propagation.
Dimensional Accuracy: All bore and interface dimensions within ±0.01 mm tolerance using high-resolution metrology tools.
Surface and Internal Integrity: SEM and NDT verified defect-free internal structure, with homogeneous γ′ phase distribution throughout cross-section.
FAQs
Why is Inconel X-750 preferred for steam and exhaust turbine disc applications?
What benefits does powder metallurgy offer over conventional forging for Inconel X-750 discs?
Can PM turbine discs be forged and heat treated for higher fatigue strength?
How does Neway AeroTech verify the mechanical performance of Inconel X-750 discs?
What industries most commonly use Inconel X-750 PM turbine discs?
