Nimonic 75 Lost Wax Casting Aerospace Exhaust Systems Company
Introduction
Nimonic 75 is a nickel-chromium alloy known for its excellent oxidation resistance, structural stability, and moderate strength at elevated temperatures up to 950°C. As a dedicated lost wax casting company, we manufacture high-performance Nimonic 75 components for aerospace exhaust systems with tight dimensional tolerances (±0.05 mm), refined grain structures, and porosity levels under 1%.
Our parts are tailored for jet exhaust ducts, afterburner liners, and thermal shielding in aerospace and aviation engine systems operating in harsh thermal environments.
Core Technology: Lost Wax Casting of Nimonic 75
Our lost wax casting process uses precision-molded wax patterns, 8–10 layers of ceramic shell, and vacuum melting at approximately 1420°C. Molds are preheated to 1050°C to enable smooth metal flow and full cavity fill. Controlled solidification (cooling rate 40–100°C/min) produces equiaxed grain sizes (0.5–2 mm) and dimensional accuracy within ±0.05 mm, essential for high-performance exhaust system components.
Material Characteristics of Nimonic 75 Alloy
Nimonic 75 is a wrought/cast nickel-chromium alloy designed for moderate high-temperature strength and excellent oxidation and scaling resistance. It performs reliably in oxidizing and thermally variable conditions. Key properties include:
Property | Value |
|---|---|
Melting Range | 1320–1380°C |
Density | 8.37 g/cm³ |
Tensile Strength (at 800°C) | ≥600 MPa |
Yield Strength (at 800°C) | ≥300 MPa |
Elongation | ≥30% |
Operating Temperature Limit | ~950°C |
Oxidation Resistance | Excellent (air, combustion gases) |
These properties make Nimonic 75 an ideal material for jet exhaust parts requiring thermal stability and corrosion resistance over extended cycles.
Case Study: Nimonic 75 Aerospace Exhaust Components
Project Background
A commercial aircraft engine supplier required lightweight, oxidation-resistant exhaust duct liners and nozzle segments operating at continuous temperatures near 900°C. Our solution: vacuum-cast Nimonic 75 components with thin-wall geometries (2–3 mm) and complex curvature profiles, meeting AMS 5599 and aerospace dimensional standards.
Typical Aerospace Exhaust System Applications
Turbofan Exhaust Nozzle Liners (e.g., CFM56, PW4000): High-temperature Nimonic 75 liners maintaining shape under cyclic loading and offering long-term oxidation protection.
Afterburner Liners (e.g., F404, EJ200): Heat-shielding components exposed to rapid thermal cycling and hot combustion gases up to 950°C.
Jet Pipe Insulation Shields (e.g., LEAP-1A): Precision-cast, corrosion-resistant panels forming thermal barriers for high-bypass exhaust configurations.
Auxiliary Power Unit (APU) Exhaust Casings: Nimonic 75 shells delivering weight savings and high oxidation resistance for onboard exhaust management systems.
These parts are engineered for thermal resilience, dimensional stability, and reliability across commercial and military propulsion systems.
Aerospace Exhaust Component Manufacturing Solutions
Casting Process Wax patterns are assembled into ceramic shell molds, sintered, and vacuum cast at ~1420°C. Solidification is controlled to produce a uniform grain structure and minimize internal shrinkage or distortion during mold cooling.
Post-processing Components undergo hot isostatic pressing (HIP) at ~1175°C and 100 MPa to remove microvoids. Final machining and grinding ensure compliance with ±0.05 mm profile accuracy for mating interfaces and bolted joints.
Surface Treatment Optional aluminizing or oxidation-resistant ceramic coatings are applied via pack cementation or plasma spray to further enhance long-term heat exposure performance in combustion gas zones.
Testing and Inspection Critical inspections include digital X-ray, CMM dimensional scanning, elevated-temperature tensile testing, and metallographic analysis to verify microstructural consistency and phase stability.
Core Manufacturing Challenges of Nimonic 75 Exhaust Components
Casting thin-walled components (2–3 mm) with complex shapes and minimal distortion.
Ensuring oxidation resistance and mechanical stability at continuous temperatures approaching 950°C.
Meeting aerospace quality and dimensional standards for form-fitting assemblies in high-flow exhaust environments.
Results and Verification
Delivered Nimonic 75 exhaust system components achieved:
Wall thickness precision within ±0.05 mm across full aerodynamic contour profiles.
Porosity <1%, validated by radiographic inspection and metallographic cross-sectioning.
Oxidation resistance validated after 1000-hour high-temperature exposure tests at 950°C.
Consistent mechanical strength ≥600 MPa at elevated operating conditions.
FAQs
Why is Nimonic 75 suitable for aerospace exhaust system components?
What tolerances and wall thicknesses can be achieved through lost wax casting?
What types of surface treatments improve Nimonic 75’s oxidation resistance?
Can Nimonic 75 components be customized for specific engine platforms?
What testing procedures are used to verify casting quality for aerospace use?
