Nimonic 90 Vacuum Investment Casting High-Pressure Reactor Components Manufacturer
Introduction
Nimonic 90 is a nickel-chromium-cobalt superalloy designed for superior high-temperature strength, oxidation resistance, and excellent creep and fatigue performance under pressure. As a specialized vacuum investment casting manufacturer, we produce Nimonic 90 components for high-pressure reactor systems with precision tolerances (±0.05 mm), controlled grain structure, and porosity below 1%.
Our castings are engineered for long-term reliability in nuclear, energy, and chemical reactor applications, where elevated temperature and pressure resistance are critical.
Core Technology: Vacuum Investment Casting of Nimonic 90
Our casting process uses 8–10 layer ceramic shell molds and vacuum melting at ~1380°C. Mold preheating at 1050–1100°C ensures complete mold fill and metallurgical cleanliness. Controlled solidification (40–90°C/min) yields equiaxed grain size of 0.5–2 mm, and casting tolerances are maintained at ±0.05 mm, essential for pressure containment integrity and sealing interfaces.
Material Characteristics of Nimonic 90 Alloy
Nimonic 90 is a precipitation-hardened nickel alloy widely used in hot-section components subjected to high stress and temperature. Key properties include:
Property | Value |
|---|---|
Melting Range | 1320–1380°C |
Density | 8.18 g/cm³ |
Tensile Strength (at 900°C) | ≥900 MPa |
Yield Strength (at 900°C) | ≥650 MPa |
Elongation | ≥18% |
Creep Rupture Strength (1000h @ 900°C) | ≥200 MPa |
Oxidation Resistance | Excellent up to 1000°C |
These properties make Nimonic 90 ideal for pressure boundary parts and mechanical elements exposed to cyclic thermal and pressure loading.
Case Study: Nimonic 90 Reactor Component Production
Project Background
A nuclear energy equipment supplier required high-pressure flange rings and containment vessel closures operating under 30 MPa at 900°C. Our team delivered precision vacuum-cast Nimonic 90 parts with fine grain structure and certified creep and fatigue performance, fully compliant with ASME Section III and RCC-M nuclear-grade requirements.
Typical Reactor Applications for Nimonic 90
EPR (European Pressurized Reactor) Flange Seals: High-strength radial sealing components used in pressurized boundaries of EDF/Framatome EPR units. Nimonic 90 ensures oxidation resistance and sealing stability over extended thermal cycles.
HTGR (High Temperature Gas-cooled Reactor) Control Mechanism Casings: Precision-cast enclosures for control rod drives in reactors such as China's HTR-PM, designed to withstand 900–950°C helium coolant exposure.
AP1000 Steam Generator Inlet Manifolds: Superalloy manifolds designed for the inlet section of passive safety-based PWR steam generators, requiring creep resistance and anti-oxidation behavior under 15 MPa pressure.
VVER-1200 Reactor Core Baffle Rings: High-temperature load-bearing components operating in saturated steam and thermal flux environments in Russian-designed VVER-1200 units, manufactured for structural integrity and dimensional accuracy.
These examples highlight Nimonic 90's capability in pressure-bearing, high-temperature, and radiation-intensive reactor environments worldwide.
Manufacturing Solutions for Reactor Components
Casting Process Wax patterns are assembled into ceramic shell molds, vacuum cast at ~1380°C, and solidified under controlled thermal gradients. Internal core elements are used for hollow castings with complex geometries.
Post-processing Hot Isostatic Pressing (HIP) at ~1180°C and 100 MPa ensures density and fatigue endurance by removing porosity. Final machining delivers precision flanges, bolt patterns, and sealing surfaces.
Post Machining After casting and HIP, components undergo specialized machining depending on application requirements. CNC machining is applied for precision sealing surfaces, bolt holes, and flatness control. For deep internal geometries or bore passages, deep hole drilling is used. In cases of hardened contours or tight corners, EDM (Electrical Discharge Machining) enables intricate finishing without mechanical stress.
Surface Treatment If required, components can be treated with aluminide or ceramic-based oxidation coatings. Surface finishing techniques, such as grinding or lapping, ensure gasket face flatness for leak-free sealing.
Testing and Inspection Every part is validated using X-ray radiographic inspection, CMM dimensional analysis, and tensile and creep testing at 900°C. Metallographic analysis confirms microstructure, grain boundary condition, and γ′ phase stability.
Core Manufacturing Challenges of Reactor-Grade Nimonic 90 Castings
Casting thick-walled components with minimal porosity for pressure resistance.
Maintaining creep strength and oxidation protection after 10,000+ hours of thermal exposure.
Ensuring dimensional compliance and sealing performance in critical bolted assemblies.
Results and Verification
Porosity <1% verified by X-ray and post-HIP metallography.
Dimensional precision of ±0.05 mm on flange and seal faces.
Tensile strength ≥900 MPa and creep rupture strength ≥200 MPa at 900°C.
No leakage or warping after simulated 1000-cycle thermal-pressure fatigue test.
FAQs
Why is Nimonic 90 suitable for high-pressure and high-temperature reactor components?
What casting tolerances can be achieved for sealing and flange surfaces?
How do you ensure creep and fatigue resistance in cast Nimonic 90 parts?
Can Nimonic 90 components be customized for nuclear-grade standards?
What testing procedures confirm integrity of pressure-boundary castings?
