Material 718:Applications,Suppliers,Choose

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Material 718 is a nickel-based superalloy that offers exceptional high temperature strength, oxidation resistance, and corrosion resistance. It is widely used in aerospace, power generation, and industrial applications where materials must withstand extreme environments. This comprehensive guide provides key details about material 718 to help engineers, designers, and procurement professionals understand its properties, applications, specifications, installation, and more.

Overview of Material 718

Material 718, also known by trade names like Inconel 718, IN718, and NS163, is a precipitation hardened nickel-chromium alloy containing significant amounts of iron, niobium, and molybdenum along with trace amounts of aluminum and titanium.

Key properties and characteristics of material 718:

Table 1: Properties and Characteristics of Material 718

CompositionNickel-chromium alloy with niobium, molybdenum, iron, aluminum, titanium
Density8.19 g/cm3
Melting Point1260-1335°C
StrengthExcellent strength from -253 to 704°C
Hardness36-41 HRC
ToughnessWithstands vibration, thermal shock, fatigue
Corrosion ResistanceResists pitting, crevice corrosion even at high temperatures
Oxidation ResistanceForms protective oxide layer up to 1000°C
WeldabilityWelds well using GTAW, GMAW, SMAW
ManufacturabilityHot worked or cold drawn into various forms
CostHigher cost than carbon steels

The unique properties of material 718 make it well suited for use in extreme temperature, pressure, corrosive, and high stress environments where high strength, hardness, and corrosion resistance are critical.

material 718
Material 718:Applications,Suppliers,Choose 3

Applications and Uses of Material 718

The exceptional properties of material 718 make it ideal for use in demanding applications including:

Table 2: Applications and Uses of Material 718

AerospaceJet engine and airframe components, blades, discs, fasteners, casings, brackets
Oil & GasDownhole tools, drill collars, wellhead equipment, valves, pumps
Power GenerationGas turbine blades, generators, steam turbine parts, heat exchangers
AutomotiveTurbocharger parts, valves, exhaust components
Chemical ProcessingReactors, piping, heat exchangers, pressure vessels
Pollution ControlSmokestack scrubbers, waste incinerators, hot gas filters
ToolingExtrusion dies, injection molds for plastics, hot work tools
MedicalImplants, prosthetics that contact bone
MarineSeawater pumps, desalinization equipment, offshore rigs
Heat TreatingFixtures, trays, baskets, hot work tools

The combination of strength, corrosion resistance, and high temperature performance makes 718 invaluable for critical parts exposed to extreme environments in key industries.

Specifications of Material 718

Material 718 is manufactured to exacting specifications that govern its chemical composition, mechanical properties, microstructure, and other quality parameters.

Table 3: Specifications and Standards for Material 718

UNS NumberN07718
AMS SpecificationAMS 5662, AMS 5663, AMS 5664
ASTM SpecificationASTM B637
ISO SpecificationISO 6207
Chemical CompositionNi 50-55%, Cr 17-21%, Nb 4.75-5.5%, Mo 2.8-3.3%, Ti 0.65-1.15%, Al 0.2-0.8%, C 0.08% max
Density8.19 g/cm3
Melting Range1260-1335°C
Mechanical PropertiesTensile strength 1241 MPa, Yield strength 1034 MPa, Elongation 12%
Grain SizeASTM 6 or finer
Hardness36-41 HRC
MicrostructureAustenitic face centered cubic (FCC) matrix with precipitation hardening

Meeting the certified specifications ensures that material 718 performs consistently across applications. Rigorous quality control and testing is done during manufacturing.

Key Design Considerations for Material 718

To leverage the full potential of material 718, engineers must design components appropriately considering factors like:

Table 4: Key Design Factors for Material 718

Design ConsiderationDetails
Strength RequirementsBalance high strength with workability, match strength levels needed
Fatigue ResistanceDesign for cyclic stress conditions, utilize precipitation hardening
Corrosion ResistanceAccount for operating environment, temperatures, stresses
TolerancesMaintain tight tolerances for fit, clearance, dimensions
Weight ReductionOptimize designs to reduce weight where possible
Cost ReductionBalance performance needs with cost, utilize trades between machining vs casting/forging
ManufacturabilityAccount for forming, machining, joining characteristics
InspectionInclude access for inspection of critical areas
TestingValidate designs meet specifications via testing
CodesAdhere to required industrial codes for the application

Thoughtful design considering these factors allows engineers to fully utilize the advantages of 718 while mitigating limitations.

Forms and Processing of Material 718

Material 718 is available from suppliers in a wide array of forms, shapes, and processing conditions to suit specific design requirements:

Table 5: Forms and Processing Options for Material 718

Bar StockHot rolled, cold drawn rounds, squares, hexesMachined parts, pump shafts, fasteners
PlateHot rolled plate, sheared plateStructural parts, casings, brackets
SheetHot rolled, cold rolled, sheared sheetShrouds, ducts, covers
TubingSeamless, weldedPiping, heat exchangers, cylinders
CastingsInvestment cast, sand castComplex shaped parts, housings
ExtrusionsHot extrudedAircraft struts, channels
ForgingsClosed die forgingsRings, discs, fasteners
WeldingGTAW, GMAW, SMAWFabricated components and assemblies
Heat TreatmentSolution anneal and age, stabilizeOptimize final properties
CoatingsElectroplated, conversion coatingsCorrosion protection
Additive MfgPowder bed, directed energy depositionComplex geometries

Choosing the optimal form and processing route enables designers to achieve the right balance of properties, performance, and cost for their specific application.

Suppliers and Availability of Material 718

As a widely used superalloy, material 718 is readily available from leading global suppliers of high performance alloys:

Table 6: Leading Suppliers of Material 718

SupplierProduct DesignationsForms Available
Haynes InternationalHaynes 718 alloyBar, sheet, plate, tube
Carpenter TechnologiesPyromet 718Bar, billet, wire
Special Metals CorpInconel 718Bar, plate, sheet, tube, welding wire
VSMPOEI-718Plate, sheet, bar
Allegheny TechnologiesU718Bar, billet, plate, sheet
Sandvik MaterialsSanicro 718Bar, wire

Material 718 is readily available with short lead times from distributors in various forms including bar, plate, sheet, tube, and welding consumables. Custom forgings, castings, and fasteners are also procurable from approved suppliers.

Table 7: Price Ranges for Material 718

FormPrice Range
Plate$8-12 per lb
Bar$7-10 per lb
Sheet$12-18 per lb
Tube$15-22 per lb
Forging$15-25 per lb
Castings$18-30 per lb

Prices vary based on order volume, size, lead time, testing/inspection requirements, and supplier. Large volume OEM agreements can reduce costs significantly.

Installation of Material 718 Components

Proper installation of material 718 components requires adherence to specifications, use of qualified procedures, and thorough documentation:

Table 8: Material 718 Installation Guidelines

HandlingUse proper lifting equipment, avoid surface damage
StorageKeep indoors, away from chemical exposure
FasteningUse specified torque values, anti-seize compounds
GasketsSelect compatible gasket materials, replace as needed
SealingEnsure leak-tight seals, quality welds for pressure containment
ConnectionsDouble check ratings for pipes, valves, fittings
DocumentationRecord torque values, leak checks, any anomalies
TestingValidate pressure tests, integrity tests prior to operation
SafetyWear personal protective equipment, safe work permits

Following qualified installation procedures is vital to prevent leaks, damage, or unsafe conditions when putting 718 systems into service. Thorough documentation provides quality records.

Operation and Maintenance of Material 718 Equipment

To achieve reliable performance and long service life from material 718 equipment, proper operation and maintenance protocols must be implemented:

Table 9: Material 718 Operation and Maintenance Guidelines

MonitoringContinuously monitor pressures, flows, temps, vibration
InspectionRegularly inspect for wear, corrosion, cracks
LubricationMaintain proper lube oil levels, change filters
SealsReplace worn or damaged seals and gaskets
FastenersCheck and re-torque critical fasteners
CleaningFollow proper procedures to remove deposits and avoid damage
OverhaulDisassemble, inspect, and repair components per schedule
DocumentationRecord operating parameters, maintenance actions
TrainingEnsure personnel are properly trained on procedures
SafetyUse lock-out tag-out, personal protective equipment

Operating and maintaining 718 equipment according to OEM guidelines ensures safe, reliable long-term performance.

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Material 718:Applications,Suppliers,Choose 4

Choosing a Reliable Material 718 Supplier

With so many suppliers offering material 718, choosing a reliable source is key to ensuring high quality consistent components:

Table 10: How to Choose a Reliable Material 718 Supplier

ConsiderationBest Practices
ReputationSelect established suppliers with proven track records
Quality SystemsISO 9001 and AS9100 certifications
Testing CapabilitiesSupplier should have extensive in-house lab testing capabilities
InventoryLook for distributors with a large stock of standard sizes to enable quick delivery
Lead TimesAsk about current lead times and availability for your specific needs
Technical SupportSupplier should provide knowledgeable technical support
DocumentationManufacturer mill certifications should be provided
Quality AssuranceAbility to provide third party inspection services
ReliabilityOn time delivery and complete orders are vital
Value AddSome offer additional services like heat treating, machining, coating

Choosing suppliers with in-depth material 718 expertise and capabilities ensures buyers get products that consistently meet specifications.

Pros and Cons of Material 718

Material 718 provides excellent performance in demanding applications, but has some limitations to consider:

Table 11: Pros and Cons of Material 718

Excellent strength at high temperaturesMore expensive than lower alloys
Resists creep, rupture, and fatigue failureSubject to strain-age cracking during forming
Withstands thermal shock and cyclingLower corrosion resistance than stainless steels
Oxidation resistant up to 1000°CRequires heat treatment to achieve full properties
Welds readily for fabricationSensitive to contamination during processing
Machinable using high performance toolingDifficult to join dissimilar metals
Formable into complex shapesLimited to continuous use up to 704°C

For optimal results, design and process engineers must work to maximize the advantages of 718 while minimizing Limitations through proper design, manufacturing, inspection, and operation.

Material 718 versus Other Superalloys

Material 718 is part of the nickel-chromium superalloy family. It offers an optimal balance of properties when compared to other superalloys:

Table 12: How Material 718 Compares to Other Superalloys

AlloyStrengthToughnessWeldabilityCorrosion ResistanceTemperature ResistanceCost
Rene 41GoodModerateGoodModerateExcellentModerate
Hastelloy XModerateExcellentExcellentExcellentGoodVery High
Haynes 230ExcellentModerateGoodExcellentExcellentHigh
Inconel 625ModerateExcellentExcellentExcellentModerateModerate

Material 718 provides the best all-around combination of strength, weldability, and corrosion resistance for many demanding applications, especially where cost is a consideration.

Material 718 and Additive Manufacturing

Additive manufacturing (AM) enables fabrication of complex 718 parts that would be extremely difficult or impossible to make via traditional methods. AM with 718 provides benefits like:

  • Ability to produce complex geometries not feasible with casting or forging
  • Reduced lead times and costs for small production volumes
  • Ability to optimize designs for performance rather than manufacturability
  • Reduced waste compared to subtractive fabrication methods
  • Ability to repair or add features to existing components
  • Potential to consolidate assemblies into single printed parts

Limitations of AM with 718 include:

  • Higher cost for large production volumes
  • Slower build rates than traditional manufacturing
  • Post-processing may be required to achieve final properties
  • Anisotropic material properties may require design adjustments
  • Qualification testing required to validate printed part performance
  • Supply chain maturity lags behind conventional production

As the technology develops, AM with 718 will see increased adoption for complex, high value applications in aerospace, energy, and industrial markets.


Q: What is material 718 used for?

A: Material 718 is most widely used in jet engines, gas turbines, chemical and petrochemical plants, and other applications requiring exceptional strength and corrosion resistance at elevated temperatures.

Q: Is material 718 weldable?

A: Yes, 718 can be readily welded using Gas Tungsten Arc Welding (GTAW), Gas Metal Arc Welding (GMAW), Shielded Metal Arc Welding (SMAW), and other welding processes. Proper procedures must be followed to avoid cracking.

Q: What is the difference between Inconel 718 and Haynes 718?

A: Both are trademarked names for alloy 718. Inconel 718 is produced by Special Metals Corporation, while Haynes 718 is produced by Haynes International. The alloys have nearly identical compositions and properties.

Q: What is the tensile strength of 718?

A: The minimum specified tensile strength of annealed and aged 718 is 1241 MPa. Actual strength can reach 1370 MPa or higher depending on processing.

Q: What metals can 718 be welded to?

A: 718 can be welded to steels, stainless steels, and dissimilar nickel alloys with proper procedures. Joint design, filler material, and post weld heat treatment are critical factors.

Q: What is the maximum operating temperature of 718?

A: While 718 has useful strength up to 1095°C, it is typically limited to continuous use up to 704°C for most applications. Higher temp capability is possible depending on loading and environment.

Q: Is material 718 compatible with 316 stainless steel?

A: Yes, 718 and 316 stainless can be successfully joined and used together when proper design, surface preparation, dissimilar welding procedures are followed.

Q: What is the difference between 718 and 725 alloys?

A: Alloy 725 has slightly improved strength and corrosion resistance thanks to additions of tantalum and niobium. 725 is more expensive but offers advantages for demanding chemical process industry applications.

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