Inconel 718 (UNS N07718) heat exchanger pipe is a precipitation-hardened nickel-chromium-iron-niobium superalloy pipe with exceptional high-temperature strength, creep resistance and fatigue resistance up to 700℃. It combines excellent corrosion resistance with outstanding mechanical properties, specially engineered for critical heat exchanger components operating in extreme high-temperature, high-pressure and high-vibration industrial environments.
As the industry-standard high-strength superalloy for aerospace and power generation applications, Inconel 718 pipe maintains its full mechanical properties after welding and long-term high-temperature exposure. It is the only material that can provide reliable performance in heat exchangers subjected to cyclic thermal and mechanical loads, making it ideal for manufacturing aerospace engine heat exchangers, gas turbine recuperators and nuclear power plant components.
| Item | Details |
|---|---|
| Executive Standards | 1. International Material Standards: ASTM B637, ASTM B670, ASME SB637, AMS 5589, AMS 5590, DIN 17752, EN 2.4668
2. Heat Exchanger Specific Standards: TEMA (Tubular Exchanger Manufacturers Association), HEI (Heat Exchange Institute), API 660, API 661 3. Corrosion Service Standards: NACE MR0175/ISO 15156, NACE MR0103 4. Testing Standards: ASTM E8 (Tensile), ASTM E23 (Impact), ASTM A450 (Hydrostatic), ASTM E243 (Eddy Current), ASTM A388 (Ultrasonic) 5. Quality Management Standards: ISO 9001, ISO 14001, AS9100, PED 2014/68/EU |
| Material Grade | 1. Main Grade: Inconel 718 (Nickel-Chromium-Iron-Niobium Precipitation-Hardened Superalloy, High-Temperature High-Strength Heat Exchanger Grade)
2. International Designations: UNS N07718, W.Nr. 2.4668, Alloy 718, NiCr19Fe19Nb5Mo3 3. Equivalent Grades: GH4169 (China), Inconel 718 (USA), Nicrofer 5219 (Germany), fully compatible with all global aerospace and industrial manufacturing standards 4. Special Grade: Ultra-low carbon version available for maximum weldability and resistance to intergranular corrosion |
| Chemical Composition (Weight %) | 1. Nickel (Ni): 50.0 – 55.0 (base element for high-temperature stability and corrosion resistance)
2. Chromium (Cr): 17.0 – 21.0 (for oxidation resistance and high-temperature strength) 3. Iron (Fe): 17.0 – 21.0 (for improved formability and cost-effectiveness) 4. Niobium + Tantalum (Nb+Ta): 4.75 – 5.50 (primary precipitation-hardening element for high strength) 5. Molybdenum (Mo): 2.80 – 3.30 (for reducing acid resistance and crevice corrosion resistance) 6. Titanium (Ti): 0.65 – 1.15 (precipitation-hardening element for improved strength) 7. Aluminum (Al): 0.20 – 0.80 (precipitation-hardening element for improved strength) 8. Cobalt (Co): ≤1.00 9. Carbon (C): ≤0.08 (standard grade); ≤0.03 (low carbon grade) 10. Manganese (Mn): ≤0.35 11. Silicon (Si): ≤0.35 12. Phosphorus (P): ≤0.015 13. Sulfur (S): ≤0.010 |
| Mechanical Properties | Annealed State (Solution Treated):
1. Tensile Strength: 860 – 1000 MPa 2. 0.2% Yield Strength: ≥415 MPa 3. Elongation (δ5): ≥45% 4. Hardness (HB): 180 – 230 Precipitation-Hardened State (Standard Heat Treatment): 1. Heat Treatment: 980℃ solution treatment + 720℃ aging (8h) + furnace cool to 620℃ + aging (8h) + air cool 2. Tensile Strength (Room Temperature): 1200 – 1400 MPa 3. 0.2% Yield Strength (Room Temperature): ≥1000 MPa 4. Elongation (δ5): ≥12% 5. Hardness (HRC): 36 – 42 6. Tensile Strength (650℃): ≥860 MPa 7. Tensile Strength (700℃): ≥760 MPa 8. Modulus of Elasticity: 205 GPa 9. Thermal Expansion Coefficient: 13.0 × 10⁻⁶ /℃ (20-100℃) |
| Dimensional Tolerance (Heat Exchanger Precision Grade) | 1. Outer Diameter Tolerance:
– Precision Cold Drawn (≤50mm): ±0.05mm – Standard Grade (50-100mm): ±0.10mm – Heavy Section (100-200mm): ±0.20mm – Ultra-Precision Grade available upon request: ±0.02mm 2. Wall Thickness Tolerance: ±10% of nominal wall thickness 3. Length Tolerance: – Fixed Length (1m-6m): ±0.5mm/m – Maximum Full-Length Tolerance: ≤2.0mm – Custom Length up to 12m available 4. Roundness Tolerance: ≤0.01mm (≤50mm); ≤0.02mm (50-100mm); ≤0.03mm (100-200mm) 5. Concentricity Tolerance: ≤0.02mm for precision machined pipes |
| Heat Exchanger Operating Conditions (Detailed) | 1. Aerospace Industry:
– Aircraft engine heat exchangers: Fuel-oil coolers, oil-air coolers, bleed air coolers, temperatures up to 700℃, pressures up to 200 bar. Inconel 718 is the only material that can withstand the extreme thermal cycling and vibration loads encountered in aircraft engines. – Gas turbine recuperators: Microturbine and industrial gas turbine heat recovery systems, temperatures up to 650℃, pressures up to 150 bar – Rocket engine components: Cryogenic fuel heat exchangers, temperatures down to -253℃ 2. Power Generation Industry: – Nuclear power plants: Reactor coolant system heat exchangers, steam generator tubes, temperatures up to 350℃, pressures up to 150 bar. Inconel 718 offers excellent resistance to radiation and high-temperature water corrosion. – Concentrated solar power (CSP) plants: Molten salt heat exchangers, temperatures up to 600℃, pressures up to 100 bar – Waste-to-energy plants: High-temperature flue gas heat exchangers, temperatures up to 650℃ 3. Oil and Gas Industry: – Ultra-deepwater offshore production: High-pressure high-temperature (HPHT) wellhead heat exchangers, temperatures up to 200℃, pressures up to 1000 bar – Sour gas processing: H₂S concentrations up to 50%, CO₂ concentrations up to 40%, temperatures up to 250℃ 4. Chemical Processing Industry: – High-pressure high-temperature reactors: Ethylene production, ammonia synthesis, temperatures up to 550℃, pressures up to 300 bar – Polymer production: Polyethylene and polypropylene reactors, temperatures up to 300℃, pressures up to 200 bar 5. Extreme Operating Conditions: – Maximum continuous operating temperature: 700℃ in oxidizing environments – Maximum continuous operating temperature: 600℃ in reducing environments – Excellent performance at cryogenic temperatures down to -253℃ – Pressure rating: up to 1000 bar depending on design and temperature |
| Heat Exchanger Tube Bundle Applications (Detailed) | 1. U-Bend Tubes:
– Application: Shell and tube heat exchangers, condensers, evaporators requiring thermal expansion compensation in high-temperature high-pressure environments – Technical Requirements: Minimum bend radius 2.0× tube diameter, no wall thinning >10% at bend, no cracking or wrinkling – Inconel 718 Advantage: Excellent hot formability, maintains full mechanical properties after bending, no post-bend heat treatment required for most applications. Superior to all other alloys in fatigue resistance after bending. – Available Sizes: OD 6mm – 50mm, wall thickness 0.8mm – 6mm, bend radii 2.0D – 10D 2. Condenser Tubes: – Application: Aerospace engine condensers, power plant surface condensers, offshore platform condensers – Technical Requirements: High corrosion resistance, excellent thermal conductivity, tight dimensional tolerances, exceptional vibration-induced fatigue resistance – Inconel 718 Advantage: 10-20x longer service life than stainless steel in high-temperature high-vibration environments, immune to fatigue cracking under cyclic loads – Available Sizes: OD 10mm – 30mm, wall thickness 1.0mm – 4mm, lengths up to 12m 3. Evaporator Tubes: – Application: Chemical evaporators, molten salt evaporators, desalination plants – Technical Requirements: Resistance to fouling, excellent heat transfer properties, resistance to thermal cycling and high pressure – Inconel 718 Advantage: Smooth surface reduces scaling and fouling, excellent thermal conductivity, withstands repeated heating and cooling cycles without deformation or fatigue cracking – Available Sizes: OD 12mm – 40mm, wall thickness 1.2mm – 5mm 4. Reboiler Tubes: – Application: Distillation columns, chemical processing reboilers, refinery reboilers – Technical Requirements: High-temperature strength, resistance to thermal fatigue, resistance to process fluids and fouling – Inconel 718 Advantage: Maintains strength at elevated temperatures, excellent resistance to thermal fatigue, no thermal deformation even after long-term high-temperature service. Resistant to coking and fouling in hydrocarbon processing. – Available Sizes: OD 16mm – 50mm, wall thickness 1.5mm – 6mm 5. Aerospace Engine Heat Exchanger Tubes: – Application: Fuel-oil coolers, oil-air coolers, bleed air coolers for commercial and military aircraft engines – Technical Requirements: Exceptional fatigue resistance, high pressure rating, tight dimensional tolerances, 100% non-destructive testing – Inconel 718 Advantage: The only material that meets the strict fatigue and strength requirements of aerospace engine applications. Proven reliability in millions of flight hours. – Available Sizes: OD 6mm – 25mm, wall thickness 0.5mm – 3mm 6. Tube Sheets and Baffles: – Application: Structural components of high-temperature high-pressure shell and tube heat exchangers – Technical Requirements: Flatness tolerance, hole position accuracy, high-temperature strength, corrosion resistance – Inconel 718 Advantage: Excellent machinability, maintains dimensional stability at high temperatures, no galvanic corrosion with Inconel 718 tubes 7. Support Rods and Spacers: – Application: Supporting tube bundles in heat exchangers operating in high-vibration environments – Technical Requirements: Straightness, high-temperature strength, corrosion resistance, exceptional fatigue resistance – Inconel 718 Advantage: Excellent straightness, immune to galvanic corrosion, long service life in the most aggressive high-vibration environments |
| Surface Quality Requirements (Detailed) | 1. Standard Pickled Surface (ASTM B637):
– Surface Finish: Ra ≤3.2μm – Process: Hot rolled, cold drawn, solution annealed, pickled and passivated – Appearance: Uniform silver-gray matte finish, free of scale, oxides and discoloration – Application: General purpose industrial heat exchanger components, tube sheets, baffles, supports – Defect Control: No cracks, folds, seams, pits, inclusions or other harmful defects allowed; minor surface imperfections ≤0.05mm deep acceptable 2. Mechanically Polished Surface: – Surface Finish: Ra ≤1.6μm (standard polish), Ra ≤0.8μm (fine polish) – Process: Pickled surface followed by centerless grinding or belt polishing – Appearance: Uniform bright metallic finish, smooth and reflective – Application: Heat exchanger tubes requiring reduced fouling, food processing applications, pharmaceutical industry – Defect Control: No visible surface defects, uniform surface texture, no grinding marks or chatter marks 3. Electropolished Surface: – Surface Finish: Ra ≤0.4μm (standard electropolish), Ra ≤0.2μm (ultra-fine electropolish) – Process: Mechanically polished surface followed by electrochemical polishing – Appearance: Mirror-like finish, extremely smooth and clean – Application: Aerospace applications, high-purity pharmaceutical applications, semiconductor manufacturing, ultra-clean heat exchangers – Defect Control: Absolutely no surface defects, uniform electropolishing across entire surface, no pitting or staining 4. Special Surface Treatments: – Passivation: All surfaces passivated according to ASTM A967 to enhance corrosion resistance – Shot Peening: Available for improved fatigue resistance in high-vibration aerospace applications – Aluminizing: Available for enhanced high-temperature oxidation resistance up to 900℃ 5. Surface Inspection: – 100% visual inspection of all surfaces by trained inspectors – Surface roughness measurement using calibrated profilometers at multiple points along each pipe – Dye penetrant inspection available upon request for critical aerospace components |
| Straightness Requirements (Detailed) | 1. Standard Straightness (ASTM B637):
– Straightness Tolerance: ≤0.5mm/m for pipes up to 6m in length – Maximum Full-Length Straightness Error: ≤3.0mm for 6m long pipes – Application: General purpose industrial heat exchanger components, baffles, supports, tube sheets 2. Precision Straightness: – Straightness Tolerance: ≤0.25mm/m for pipes up to 6m in length – Maximum Full-Length Straightness Error: ≤1.5mm for 6m long pipes – Application: Heat exchanger tubes, tube bundle support rods, long components requiring tight alignment 3. Ultra-Precision Straightness: – Straightness Tolerance: ≤0.1mm/m for pipes up to 6m in length – Maximum Full-Length Straightness Error: ≤0.6mm for 6m long pipes – Application: Aerospace heat exchangers, nuclear power applications, high-precision industrial heat exchangers 4. Straightening Process: – All pipes undergo multi-roll straightening after solution annealing – Precision pipes undergo additional centerless grinding and straightening – Straightness verified using laser straightness measurement systems with 0.01mm accuracy 5. Importance of Straightness: – Ensures proper alignment of tube bundles, preventing tube-to-tube contact and wear – Reduces vibration and noise in operating heat exchangers – Facilitates easy assembly and installation, reducing labor costs – Prevents stress concentrations that could lead to premature fatigue failure – Ensures uniform heat transfer across the entire tube bundle |
| Eddy Current Testing (ET) (Detailed) | 1. Testing Standard: ASTM E243, ASME V Article 8, TEMA RCB-7.3, AMS 2631
2. Testing Frequency: 100% of all heat exchanger pipes undergo eddy current testing 3. Equipment: Computerized multi-frequency eddy current testing systems with automatic defect marking and digital data recording 4. Testing Parameters: – Frequency Range: 10kHz – 2MHz depending on pipe diameter and wall thickness – Sensitivity: Calibrated to detect artificial defects of 0.2mm depth (3% of wall thickness) or smaller – Defect Types Detected: Surface cracks, subsurface cracks, pits, inclusions, seams, laps and wall thickness variations 5. Testing Procedure: – Pipes pass through encircling coils at controlled speed (1-3m/s) – System automatically records all test data and marks defective areas with paint – Defective sections are cut out and removed – Retesting performed on repaired sections to ensure compliance 6. Acceptance Criteria: – No defects exceeding 3% of wall thickness allowed – No linear defects of any length allowed – Isolated pits ≤0.2mm deep acceptable if spaced ≥100mm apart 7. Additional Testing Options: – Ultrasonic Testing (UT) according to ASTM A388 for internal defect detection – Dye Penetrant Testing (PT) according to ASTM E165 for surface defect detection – Magnetic Particle Testing (MT) not applicable as Inconel 718 is non-magnetic 8. Documentation: – Complete eddy current test report provided with each shipment – Test data stored digitally for minimum 20 years for traceability |
| Hydrostatic Pressure Testing (Detailed) | 1. Testing Standard: ASTM A450, ASME B31.3, TEMA RCB-7.2, AMS 5589
2. Testing Frequency: 100% of all heat exchanger pipes undergo hydrostatic pressure testing 3. Test Pressure Calculation: – Standard Test Pressure: 1.5× design pressure – Minimum Test Pressure: 20 bar – Maximum Test Pressure: Limited by yield strength (≤80% of yield strength at test temperature) 4. Test Medium: – Deionized water with chloride content ≤25ppm to prevent corrosion – Optional corrosion inhibitors added for long-term storage – Water temperature maintained between 10℃ and 50℃ to prevent condensation 5. Testing Procedure: – Pipes are sealed at both ends with high-pressure hydraulic fittings – Water is pumped into the pipe until test pressure is reached – Pressure held for minimum 15 seconds (standard) or 30 seconds (aerospace applications) – Visual inspection for leaks, bulging or deformation during pressure holding – Pressure released and pipes drained and dried after testing 6. Acceptance Criteria: – No leakage of any kind allowed – No permanent deformation or bulging allowed – No pressure drop during holding period allowed 7. Additional Testing Options: – Pneumatic pressure testing available upon request using dry nitrogen – Burst pressure testing available for design verification – Cyclic pressure testing available for fatigue life evaluation 8. Post-Testing Processing: – Pipes are thoroughly dried internally and externally using compressed air – Ends are capped immediately to prevent moisture ingress during storage and transportation – Optional passivation performed after testing to restore corrosion resistance |
| Fixed Length Specifications (Detailed) | 1. Standard Fixed Lengths:
– 1000mm, 2000mm, 3000mm, 4000mm, 5000mm, 6000mm – Length Tolerance: ±0.5mm/m, maximum ±2.0mm for 6m lengths – Squareness of Cut: ≤0.1mm per 100mm diameter 2. Custom Fixed Lengths: – Any length from 100mm to 12000mm available upon request – Length Tolerance: ±0.3mm for lengths ≤3m, ±0.5mm for lengths >3m – Ultra-precision cutting available with tolerance ±0.1mm 3. Long Length Products: – Maximum single length: 12000mm – Ideal for large heat exchangers requiring long tubes without welded joints – Reduces number of welds, improving reliability and reducing maintenance costs 4. Cutting Methods: – Band saw cutting for standard lengths – CNC lathe cutting for precision lengths with square ends – Abrasive cutting for small diameter pipes – Water jet cutting available for sensitive materials 5. End Preparation: – All cut ends deburred and chamfered as standard – Optional end facing and turning available 6. Length Verification: – All lengths verified using calibrated measuring tapes or laser distance meters – 100% inspection of all cut lengths 7. Packaging by Length: – Pipes bundled by length to facilitate easy identification and handling – Long pipes packaged in steel frames to prevent bending during transportation |
| Tube End Processing Standards (Detailed) | 1. Plain Square End (Standard):
– Standard: ASME B16.25, TEMA RCB-7.4 – Dimensions: Ends cut square to within 0.1mm per 100mm diameter – Chamfer: 0.5×45° external chamfer to remove burrs – Application: General purpose tube-to-tubesheet welding, expansion joints 2. Beveled End for Welding: – Standard: ASME B16.25, AWS D10.9 – Bevel Angle: 30° ±2.5° (standard), 37.5° ±2.5° (heavy wall) – Root Face: 1.6mm ±0.8mm – Application: High-pressure piping, tube-to-tubesheet welding in critical aerospace and nuclear applications 3. Chamfered End: – Standard: Customer specific – Chamfer Angles: 15°, 30°, 45°, 60° available – Chamfer Length: 1mm – 10mm depending on wall thickness – Application: Tube expansion, assembly into fittings 4. Expanded End: – Standard: TEMA RCB-7.5 – Expansion Ratio: Up to 12% of original diameter – Length of Expansion: 10mm – 50mm depending on tube diameter – Application: Tube-to-tubesheet expansion joints, quick connect fittings 5. Swaged End (Reduced End): – Standard: ASME B16.19 – Reduction Ratio: Up to 40% of original diameter – Length of Swage: 2× diameter minimum – Application: Connection to smaller diameter piping, nozzles 6. Flared End: – Standard: SAE J514, ISO 8434 – Flare Angle: 37° (JIC), 45° (SAE), 60° (metric) – Application: Flare fittings, hydraulic connections 7. Threaded End: – Standard: NPT, BSPP, BSPT, metric threads – Thread Class: Class 2A (external), Class 2B (internal) – Application: Threaded connections, instrumentation fittings 8. End Protection: – All tube ends protected with plastic caps during storage and transportation – Heavy-duty metal caps available for heavy wall pipes – Ends sealed to prevent moisture and contamination ingress |
| Why Choose Us (Emily PIPE) | 1. 20+ Years of Superalloy Expertise: We have been manufacturing and exporting high-performance nickel alloy heat exchanger components for over 20 years, with deep understanding of the unique requirements of aerospace, power generation and high-pressure industrial environments.
2. Complete International Certifications: Our production facilities are certified to ISO 9001, ISO 14001, AS9100 and PED, with all products complying with ASTM, ASME, NACE, API and AMS standards. 3. Dedicated Inconel 718 Production Line: We operate a dedicated production line for Inconel 718 products, ensuring strict control over chemical composition, heat treatment parameters and mechanical properties. 4. In-House Heat Treatment Facility: We operate a fully equipped heat treatment facility that can perform precise solution annealing and precipitation hardening treatments, ensuring consistent mechanical properties across all batches. 5. Full-Process Quality Control: We implement a comprehensive quality control system from raw material inspection to finished product testing, including 100% eddy current testing and hydrostatic testing for all heat exchanger pipes. 6. Advanced Customization Capability: We can produce custom sizes, lengths, surface finishes and end treatments according to your drawings and technical specifications, including complex U-bend tubes and large tube sheets. 7. Global One-Stop Service: We handle everything from material production and custom processing to international shipping and customs clearance, with reliable logistics partners ensuring on-time delivery to any industrial facility worldwide. 8. Professional Technical Support: Our team of metallurgical engineers and heat exchanger specialists provides expert guidance on material selection, heat treatment optimization and fabrication techniques. |
| Inquiry Guidance Words | 1. If you need high-quality Inconel 718 heat exchanger pipes for your aerospace, power generation or high-pressure industrial project, please send us your specific requirements including dimensions, quantity, required standards, heat treatment condition and delivery date, and we will provide a detailed quotation within 12 hours.
2. For any questions about material properties, heat treatment parameters, high-temperature performance or heat exchanger design recommendations, our alloy specialists are available to assist you promptly. 3. Emily PIPE is your trusted partner for high-performance superalloy heat exchanger solutions. Contact us today to discuss how our Inconel 718 products can help you improve the reliability and service life of your heat exchangers in the most demanding operating conditions. |
| Supplementary Industry Information | 1. Comprehensive Test Reports: Each batch comes with a full Material Test Report (MTR) including chemical composition analysis, mechanical properties testing, heat treatment records, eddy current test results and hydrostatic test results.
2. Full Material Traceability: Every pipe comes with a unique heat number and complete traceability documentation from raw material ore to finished product, meeting the strictest aerospace and nuclear project requirements. 3. Value-Added Processing: We offer comprehensive value-added services including precision cutting, machining, bending, welding, end forming and assembly, providing ready-to-install heat exchanger components. 4. Professional Industrial Packaging: We use protective plastic caps on both ends, anti-corrosion wrapping, wooden crates and steel frames to prevent damage during long-distance international transportation. 5. Urgent Order Support: We maintain a large inventory of standard Inconel 718 pipe sizes in both annealed and precipitation-hardened conditions, enabling us to fulfill urgent orders within 7-15 days. 6. Prototype Development Support: We support small batch prototype orders with fast turnaround times to help you accelerate product development and testing. 7. After-Sales Service: We provide lifetime technical support for all our products, including on-site assistance for fabrication, installation and troubleshooting. 8. Sustainability Commitment: All our products are manufactured using sustainable practices and are 100% recyclable, helping you meet your environmental targets. |