Inconel 718 is a high-performance precipitation-hardened nickel-based superalloy, specifically engineered for the harsh and complex marine and offshore environments. It boasts exceptional resistance to seawater, salt spray, and marine atmospheric corrosion, coupled with outstanding high-temperature strength, creep resistance, impact toughness, and fatigue resistance. This alloy maintains stable mechanical properties under long-term immersion in seawater, alternating temperature and humidity, strong wind and wave impact, and high-load operating conditions. With reliable welding performance, easy precision machining, and strict quality control, it fully complies with international marine and offshore industry standards, serving as a core material for key components of offshore platforms, marine vessels, subsea equipment, and coastal engineering, ensuring safe, durable, and long-term operation in extreme marine and offshore scenarios.
Basic Information
| Item |
Details |
| Material Grade |
Inconel 718, UNS N07718, W.Nr. 2.4668, DIN 2.4668 |
| Executive Standards |
ASTM B637, ASTM B622, ASTM B670, ASME SB-637, ABS (American Bureau of Shipping), DNV (Det Norske Veritas), LR (Lloyd’s Register), API 5L (Offshore Pipeline), ISO 15156 (Corrosion Resistance) |
| Delivery Condition |
Solution annealing + aging treatment, marine/offshore grade anti-corrosion surface treatment |
| Applicable Scenarios |
Offshore platforms (fixed/floating), subsea equipment, marine vessels, coastal engineering, offshore drilling, offshore wind power, marine pipelines |
| Surface Treatment |
Marine grade pickling, passivation, anti-corrosion coating (epoxy, fluorocarbon) optional, subsea anti-fouling treatment available |
| Operating Temperature Range |
-50℃ ~ 650℃ |
Mechanical Properties (Marine/Offshore Grade, Solution & Aging Treated)
| Performance Index |
Standard Minimum Value |
| Tensile Strength |
≥1275 MPa |
| 0.2% Yield Strength |
≥1035 MPa |
| Elongation |
≥12% |
| Reduction of Area |
≥40% |
| Hardness |
≤44 HRC (anti-wear treatment optional up to 55 HRC) |
| Impact Toughness (Room Temperature) |
≥60 J/cm² |
| Low-Temperature Impact Toughness (-40℃) |
≥50 J/cm² |
| High-Temperature Creep Strength |
≥690 MPa (650℃, 1000h) |
| Corrosion Resistance |
No rust after 1000h salt spray test; excellent resistance to seawater, brine, and marine pollutants |
| Fatigue Life |
≥10⁷ cycles under alternating load (marine vibration scenario) |
Dimensional Tolerance (Marine/Offshore Grade Precision)
| Specification |
Tolerance Standard |
| Outer Diameter |
Comply with ASTM B637 and offshore industry standards, tolerance ±0.02mm (precision grade); subsea pipeline ±0.01mm |
| Wall Thickness |
Strict deviation control, ±0.015mm, ensuring pressure-bearing capacity and corrosion resistance for offshore pipelines |
| Product Length |
Custom fixed length (2m~20m) or cut-to-size, tolerance ±0.4mm/m; offshore long pipelines support continuous length |
| Straightness & Roundness |
Straightness ≤0.2mm/m; Roundness ≤0.015mm, meeting offshore component assembly and pipeline laying requirements |
| Surface Roughness |
Marine grade pickling: Ra ≤0.8μm; subsea components: Ra ≤0.6μm, no burr, no defects, easy for anti-corrosion/anti-fouling treatment |
Why Marine and Offshore Industry Uses Inconel 718
| Core Advantage |
Industry Application Reason |
| Superior Seawater Corrosion Resistance |
Resists long-term immersion in seawater, salt spray, and marine atmospheric corrosion, avoiding component rust, perforation, and failure |
| Excellent High-Temperature Performance |
Adapts to offshore drilling, offshore power generation, and marine engine high-temperature working environments (up to 650℃) |
| Strong Impact & Fatigue Resistance |
Withstands wind, wave, and marine vessel/offshore platform vibration, ensuring structural stability in harsh marine conditions |
| Good Welding Performance |
Facilitates on-site welding of large offshore structures (platforms, pipelines) and marine components, ensuring welding strength and integrity |
| High Load-Bearing Capacity |
Meets offshore platform, subsea equipment, and marine vessel load-bearing requirements, ensuring safe operation |
| Long Service Life |
Stable performance for 20-30 years, matching the service life of offshore platforms and marine vessels, reducing maintenance costs |
| Compliance with Industry Standards |
Recognized by ABS, DNV, LR, and API, meeting international marine/offshore norms and classification society requirements |
| Low-Temperature Adaptability |
Maintains stable performance in cold marine areas and subsea low-temperature environments, avoiding brittle fracture |
Applicable Working Conditions (Marine & Offshore Scenarios)
| Application Field |
Actual Working Condition |
| Offshore Platforms (Fixed/Floating) |
Seawater immersion, salt spray corrosion, strong wind and wave impact, long-term outdoor operation, high load |
| Subsea Equipment (Valves, Pipes) |
Deep-sea high pressure (up to 100MPa), low temperature, seawater corrosion, no maintenance for long periods |
| Marine Vessels (Cargo, Cruise, Naval) |
Seawater immersion, marine fuel erosion, navigation vibration, storm impact, alternating temperature |
| Offshore Drilling Equipment |
High temperature, high pressure, drilling fluid corrosion, salt spray, outdoor harsh environment |
| Offshore Wind Power Equipment |
Seawater corrosion, strong wind vibration, long-term outdoor operation, salt spray erosion |
| Marine Pipelines (Seawater/Fuel) |
High pressure, seawater/fuel conveying, long-distance laying, marine environmental corrosion |
| Coastal Engineering Components |
Seawater immersion, tidal erosion, marine atmospheric corrosion, alternating wet and dry conditions |
Core User Demands in Marine and Offshore Industry
| User Demand |
Specific Requirement |
| Corrosion Resistance |
Resist seawater, salt spray, and marine pollutants, ensuring long service life without failure |
| Structural Safety |
High strength, impact resistance, and fatigue resistance, avoiding component damage in harsh marine/offshore conditions |
| High-Temperature & Pressure Adaptability |
Adapt to offshore drilling, power generation, and subsea high-temperature, high-pressure environments |
| Weldability |
Good welding performance, suitable for on-site assembly of large offshore structures and pipelines |
| Standard Compliance |
Meet international classification society (ABS/DNV/LR) and API standards for project acceptance |
| Batch Stability |
Consistent performance for large-scale offshore/marine projects, ensuring component matching |
| Customization Capability |
Support non-standard size, anti-corrosion/anti-fouling treatment, and special heat treatment for subsea/offshore scenarios |
| Complete Documentation |
Provide full set of test reports and certification for classification society review and project bidding |
| Subsea Adaptability |
For subsea equipment, require high pressure resistance and long-term maintenance-free performance |
Common Matching Products for Marine and Offshore Industry
| Product Category |
Main Usage |
| Inconel 718 Seamless Tube |
Offshore pipelines, subsea pipelines, marine cooling/fuel pipelines, offshore wind power cooling tubes |
| Inconel 718 Alloy Bar |
Offshore platform fasteners, valve stems, pump shafts, marine propeller shafts, drilling equipment components |
| Inconel 718 Steel Plate |
Offshore platform structural plates, hull liners, offshore wind power tower flanges, coastal engineering anti-corrosion plates |
| Inconel 718 Pipe Fittings |
Marine/offshore pipeline elbows, tees, flanges, reducers (seawater corrosion-resistant, high-pressure bearing) |
| Inconel 718 Forgings |
Offshore valve bodies, pump impellers, marine propellers, offshore platform connectors, drilling tool components |
| Inconel 718 Precision Parts |
Subsea instrument components, marine navigation equipment parts, offshore wind power auxiliary accessories |
| Inconel 718 Welded Parts |
Offshore platform structural weldments, large marine component assemblies |
Marine/Offshore Special Requirements
| Item |
Details |
| Anti-Corrosion & Anti-Fouling |
Marine grade passivation, epoxy/fluorocarbon anti-corrosion coating; subsea components add anti-fouling coating to prevent marine organism adhesion |
| Quality Inspection Process |
100% PMI spectral analysis, UT/MT/RT nondestructive testing, salt spray corrosion test, high-pressure test (for pipelines), fatigue test |
| Traceability System |
Full material traceability from raw material to finished product, complete production, processing, and inspection records (meets offshore project requirements) |
| Packaging Requirements |
Marine anti-corrosion, moisture-proof, rust-proof packaging; subsea components use sealed packaging to avoid contamination |
| Transportation Standard |
Comply with international marine transportation regulations, anti-corrosion, anti-collision, suitable for long-distance sea/land transportation |
| Installation Guidance |
Provide professional on-site welding, installation, and maintenance guidance for offshore and subsea components |
Marine/Offshore Certifications & Test Reports
| Certification/Report Type |
Details |
| Quality Certification |
ISO 9001, ABS (American Bureau of Shipping) Certification, DNV (Det Norske Veritas) Approval, LR (Lloyd’s Register) Certification, API 5L Certification |
| Test Reports |
EN10204 3.1/3.2 (Marine/Offshore Grade), MTR Material Test Report, PMI Spectral Analysis Report, Salt Spray Corrosion Test Report, UT/MT/RT Nondestructive Testing Report, High-Pressure Test Report, Fatigue Test Report |
| Industry Compliance |
Meet IMO (International Maritime Organization) standards, ISO 15156 (corrosion resistance for oil and gas industry), offshore environmental protection requirements |
Packaging
We adopt export-standard packaging, including wooden cases, bundling packaging, plastic end caps and waterproof films to ensure safe transportation.
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