Nimonic 80A Investment Casting Power Generation Turbine Components Foundry
Introduction
Nimonic 80A is a precipitation-hardened nickel-chromium alloy reinforced with titanium and aluminum, offering excellent high-temperature strength, oxidation resistance, and creep resistance up to 870°C. At our specialized investment casting foundry, we manufacture precision Nimonic 80A components for power generation turbines with tight dimensional control (±0.05 mm), uniform grain structures, and porosity levels below 1%.
Our castings are engineered for long-life, high-load operation in industrial steam and gas turbines where thermal stability and fatigue resistance are essential.
Core Technology: Investment Casting of Nimonic 80A
Our Nimonic 80A turbine components are manufactured using ceramic shell investment casting under vacuum, with alloy pouring at 1350–1380°C and mold preheating at 1000–1100°C. Controlled solidification (cooling rate: 40–90°C/min) yields equiaxed grain sizes of 0.5–2 mm. Tolerances are maintained within ±0.05 mm, ideal for close-fit turbine applications.
Material Characteristics of Nimonic 80A Alloy
Nimonic 80A is a nickel-based alloy used widely in turbine blades, bolts, discs, and other hot-section hardware. It combines strength, fatigue resistance, and oxidation stability under continuous thermal stress. Key properties include:
Property | Value |
|---|---|
Melting Range | 1320–1380°C |
Density | 8.19 g/cm³ |
Tensile Strength (at 750°C) | ≥825 MPa |
Yield Strength (at 750°C) | ≥590 MPa |
Elongation | ≥20% |
Operating Temperature Limit | ~870°C |
Oxidation Resistance | Excellent |
Creep Resistance (1000h @ 750°C) | ≥140 MPa |
These properties make Nimonic 80A an excellent material for components subjected to high stress and thermal cycling in rotating and static turbine assemblies.
Case Study: Nimonic 80A Turbine Component Production
Project Background
A global energy equipment manufacturer required turbine wheel segments and stator support brackets capable of continuous service at 800–850°C in an industrial steam turbine. We delivered vacuum-cast Nimonic 80A parts conforming to ASTM B637 standards, with consistent wall thicknesses, low shrinkage, and robust creep performance under cyclic thermal conditions.
Typical Power Generation Turbine Applications
Steam Turbine Nozzle Rings: Static rings cast in Nimonic 80A to resist thermal shock and oxidation at 700–850°C in base-load utility systems.
Gas Turbine Blade Platforms: Precision components located in transition zones between rotating and stationary elements, where fatigue resistance is critical.
Turbine Stator Support Brackets: Fixed assemblies holding blade arrays, requiring consistent mechanical strength and dimensional stability under heavy load cycles.
Turbine Retaining Bolts and Seal Plates: Cast components used to anchor hot-section assemblies exposed to vibration and long-term heat exposure.
These components support the thermal efficiency and structural integrity of power turbines in demanding operational environments.
Turbine Component Manufacturing Solutions
Casting Process Wax patterns are coated with ceramic slurries to build 8–10 shell layers. After dewaxing and sintering, molds are vacuum cast at ~1360°C. Controlled solidification avoids segregation and ensures uniform carbide and γ′ distribution for creep strength.
Post-processing Parts are subjected to Hot Isostatic Pressing (HIP) at 1175°C and 100 MPa to eliminate microporosity and increase fatigue life. Final CNC machining guarantees dimensional precision and sealing surface flatness.
Surface Treatment Depending on service location, thermal barrier coatings (TBC) or oxidation-resistant coatings are applied via plasma spray to extend part life under high-temperature gas flow or steam erosion.
Testing and Inspection Each part is inspected by X-ray radiography, CMM dimensional scanning, and high-temperature tensile testing. Metallographic analysis confirms grain refinement and carbide uniformity.
Core Manufacturing Challenges of Nimonic 80A Turbine Parts
Casting thin-walled structures with complex geometry while preventing hot tearing and shrinkage.
Achieving porosity <1% and dimensional control within ±0.05 mm for rotor- and stator-mounted hardware.
Ensuring long-term creep resistance and oxidation durability under multi-decade operational loads.
Results and Verification
Delivered components demonstrated:
Consistent grain structure (0.5–2 mm) and porosity below 1%.
Tensile strength ≥825 MPa and yield strength ≥590 MPa at 750°C.
High dimensional repeatability validated by 3D CMM measurements.
No coating delamination or surface degradation after 1000-hour cyclic oxidation testing at 850°C.
FAQs
What makes Nimonic 80A ideal for power turbine components?
What dimensional tolerances can be achieved using investment casting?
Can Nimonic 80A components be customized with internal cooling features?
What are the typical post-processing and coating options for hot-section parts?
How is casting integrity and mechanical compliance verified before delivery?
