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Relaxation Resistant Solution Treated Inconel X750 Round Bar for Core Fasteners
Engineered for critical nuclear core structural components and high-stress fastening systems, our solution-treated and aged Inconel X750 round bars deliver exceptional resistance to stress relaxation, irradiation-assisted stress corrosion cracking, and high-temperature creep up to 700°C.
- Overview
- Specifications
- Features
- Applications
- Why-Us
- FAQ
- Recommended Products
Product Summary
| Item | Value |
|---|---|
| Grade | Inconel X750 (Precipitation Hardening Ni-Cr) |
| Condition | Solution Annealed / Solution Treated & Aged |
| Form | Precision Ground Round Bar / Solid Rod |
| Diameter | 3.0 - 350 mm (Customizable) |
| Tolerance | h7 / h8 |
| Surface | Centerless Ground / Polished / Peeled / Turned |
| Function | Low Thermal Relaxation, High Yield Strength |
Product Overview
High Stability Inconel X750 Metallurgy for Nuclear Core Fastening: Inconel X750 is a precipitation-hardenable nickel-chromium-iron superalloy alloyed with titanium and aluminum for gamma prime phase strengthening, alongside niobium for enhanced structural stability. When subjected to advanced vacuum induction melting followed by electroslag remelting (VIM+ESR), the alloy achieves ultra-low residual gas content, minimal micro-segregation, and optimized grain boundary chemistry.
For critical nuclear reactor core fasteners, guide tube support pins, and high-load reactor hold-down springs, material stability under continuous thermal and neutron flux is paramount. Our solution-treated Inconel X750 round bars undergo specialized triple-stage thermal processing that establishes homogeneous solid solution matrices and uniform gamma prime precipitation. This precise microstructure prevents stress relaxation under persistent elastic preloads and mitigates secondary creep failure mechanisms across operating temperatures exceeding 650°C.
Technical Specifications and Relaxation Resistant Performance Parameters:
Chemical Composition (wt%)
| Element | Ni + Co | Cr | Fe | Ti | Al | Nb | Mn | Si | C | S | P |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Range | ≥ 70.0 | 14.0 - 17.0 | 5.0 - 9.0 | 2.25 - 2.75 | 0.40 - 1.00 | 0.70 - 1.20 | ≤ 1.00 | ≤ 0.50 | ≤ 0.08 | ≤ 0.010 | ≤ 0.015 |
Typical Mechanical Properties (Solution Treated & Aged)
| Property | Value |
|---|---|
| Tensile Strength (Rm) | 1250 - 1450 MPa |
| Yield Strength (Rp0.2) | 850 - 1050 MPa |
| Elongation (A5) | 18 - 25% |
| Hardness | 32 - 38 HRC |
| Elastic Modulus (20°C) | 214 GPa |
| Stress Relaxation (550°C, 1000h, 400 MPa) | < 4.5% |
| Service Temperature | -200°C to +700°C |
Engineered Advantages of High Purity Inconel X750 Round Bars:
- Outstanding Thermal Stress Relaxation Resistance: Maintains vital clamping force and bolt preload over tens of thousands of operating hours in extreme core environments.
- High-Temperature Creep Rupture Strength: Fine dispersion of intermetallic precipitates prevents microstructural coarsening and intergranular slippage at elevated temperatures.
- Stress Corrosion Cracking Immunity: Controlled solution annealing eliminates harmful grain boundary carbide films, providing robust defense against primary water stress corrosion cracking (PWSCC).
- Strict Ultrasonic Cleanness: High-grade double vacuum melting ensures zero internal macro-inclusions, achieving 100% volumetric ultrasonic inspection pass rates.
- Precision Dimensional Tolerances: Advanced centerless grinding guarantees tight diametrical tolerances and concentricity for rapid high-speed thread rolling and CNC machining.
Critical Fastening and Structural Applications in Nuclear and Heavy Industry:
- Nuclear Power Engineering: Reactor pressure vessel internal fasteners, control rod drive mechanism springs, core shroud tie rods, core baffle bolts, and fuel assembly support pins.
- Gas Turbines and Aviation: High-temperature casing bolts, turbine rotor locking pins, nozzle guide vane fasteners, and thermal barrier clamping rings.
- High Temperature Valve Systems: Cryogenic-to-superheated valve stems, severe service bonnet studs, and high-pressure chemical reactor spring seals.
- Precision Tooling and Hot Forming: High-load springs and fixtures operating under continuous cyclic thermal stress.
Why Choose DLX for Nuclear Grade Superalloy Materials?
DLX is a specialized manufacturer and global engineering partner in high-performance nickel, cobalt, and precision resistance alloy production. We operate integrated manufacturing lines spanning vacuum induction melting (VIM), electroslag remelting (ESR), precision forging, hot rolling, cold drawing, and automated centerless grinding.
- Robust Monthly Capacity: A dedicated production infrastructure delivering 1,200 tons per month, guaranteeing stable lead times and volume scalability for global projects.
- Complete In-House Quality Assurance: Equipped with direct-reading optical emission spectrometers, LECO carbon/sulfur and oxygen/nitrogen analyzers, computerized tensile testing, and automated immersion ultrasonic flaw detection.
- Strict Batch Traceability: Full heat-number traceability with detailed inspection documentation accompanying every shipment.
- Flexible Engineering Fulfillment: Tailored dimensional executions, customizable heat treatment recipes, and responsive prototyping support adapted to project-specific drawing requirements.
Frequently Asked Questions Regarding Inconel X750 Round Bars for Fasteners:
Q1: Why is solution treatment critical for Inconel X750 used in nuclear reactor core fasteners?
A1: Solution treatment dissolves coarse secondary phases and homogenizes alloying elements like titanium, aluminum, and niobium throughout the matrix. When followed by controlled precipitation aging, it produces an ultra-fine, uniform distribution of gamma prime strengthening phases. This state is essential for achieving maximum resistance against stress relaxation and intergranular stress corrosion cracking under nuclear operating conditions.
Q2: How does DLX ensure the low stress relaxation performance of Inconel X750 bars?
A2: We utilize high-purity VIM+ESR double-melting techniques to strictly limit trace impurities such as lead, bismuth, and sulfur. Combined with uniform hot-working reduction ratios and precise multi-zone temperature-controlled continuous heat treatment, our round bars deliver consistent microstructural stability that limits relaxation rates to minimal levels under prolonged high-temperature load.
Q3: What surface finishes and dimensional tolerances can be supplied for CNC fastener manufacturing?
A3: We supply centerless ground and polished round bars with diametrical tolerances tight to h7 or h8, surface roughness Ra up to 0.4 micrometers, and superior straightness (less than 0.5 mm per meter). This enables direct feeding into automated Swiss-type lathes and thread rolling equipment without preliminary turning passes.
Q4: What certifications and inspection reports are provided with each order?
A4: Every batch is delivered with comprehensive physical and chemical inspection records, including complete chemical spectral analyses, mechanical tensile and hardness testing, grain size verification, and full-length non-destructive ultrasonic and eddy current inspection results.
Q5: What are the packaging and shipping standards to prevent transit damage and corrosion?
A5: Round bars are individually protected with rust-inhibiting wrapping, bundled securely, and packed into reinforced wooden crates with internal waterproof lining to prevent mechanical scratching, bending, or surface oxidation during international transit.
