Inconel 718 Sheet Plate: Aerospace and Turbine Applications

Introduction

Inconel 718 sheet plate is a nickel-chromium precipitation-hardening alloy product used for aerospace, gas turbine, high-temperature, cryogenic and high-strength corrosion-resistant components. It is selected when buyers need a combination of high tensile strength, fatigue resistance, creep resistance, oxidation resistance and good fabricability in demanding service environments.

Inconel 718, also known as Alloy 718 or UNS N07718, is widely supplied as sheet, plate, strip, bar, forging, pipe, tube and fastener stock. For sheet and plate applications, it is commonly specified for turbine engine parts, combustor components, hot-section structures, aerospace brackets, cryogenic hardware, springs, seals, formed components and high-strength fabricated assemblies. Buyers should define the product standard, thickness, width, length, heat treatment, surface condition, mechanical properties, grain size, testing and certificate requirements before ordering.

Application Scenarios for Inconel 718 Sheet and Plate

Inconel 718 sheet and plate are used where stainless steel, standard nickel alloys or lower-strength materials cannot provide enough strength at temperature. The alloy is especially important in aerospace and turbine systems because it can maintain useful mechanical properties under high stress, vibration and thermal cycling.

Application Scenario	Why Inconel 718 Is Used	Specification Focus
Aerospace Engine Components	High strength, fatigue resistance and elevated-temperature capability	AMS or OEM standard, heat treatment, tensile properties and traceability.
Gas Turbine Parts	Resistance to thermal cycling, oxidation and mechanical stress	Plate thickness, surface quality, heat treatment and NDT.
Combustor and Hot-Section Structures	Strength retention and oxidation resistance at elevated temperature	Sheet flatness, forming condition, weldability and surface condition.
Cryogenic Equipment	Good strength and toughness at very low temperatures	Impact or low-temperature property requirements where specified.
Springs and Seals	Precipitation-hardening response and fatigue resistance	Strip thickness, hardness, temper and surface finish.
Machined High-Strength Plate Parts	High load capacity and dimensional stability after proper processing	Machining allowance, UT, hardness, heat treatment and flatness.

Material Benefits of Inconel 718

Inconel 718 is strengthened mainly through precipitation hardening. Compared with many solid-solution nickel alloys, it can provide higher strength after appropriate heat treatment while still maintaining useful weldability and fabrication performance.

• High strength: suitable for aerospace brackets, turbine hardware and high-load machined parts.

• Fatigue resistance: useful for rotating, vibrating and cyclically loaded components.

• Elevated-temperature performance: commonly selected for high-temperature engine and turbine environments.

• Oxidation resistance: supports service in hot gas and thermal cycling conditions.

• Corrosion resistance: provides better performance than many stainless steels in selected aggressive environments.

• Weldability: generally good for a precipitation-hardening nickel alloy when qualified procedures are used.

• Broad product form availability: sheet, plate, strip, bar, wire, forging and fastener stock can be supplied for integrated projects.

Inconel 718 Sheet Plate Product Data

Specification Item	Typical Requirement
Material	Inconel 718 / Alloy 718 / UNS N07718 / W.Nr. 2.4668
Product Form	Sheet, plate, strip, coil, cut plate, machined blank or custom size
Common Product Standards	ASTM B670 / ASME SB670, AMS specifications or customer standards
Condition	Solution annealed, age hardened, annealed, cold rolled or hot rolled depending on specification
Surface	Mill finish, pickled, ground, polished or customer-specified surface
Common Testing	Chemical analysis, tensile test, hardness, dimensional inspection, surface inspection and UT where required
Certificate	EN 10204 3.1 MTC, AMS documentation, third-party inspection or full data book where required

Sheet vs Plate: How to Choose

The choice between Inconel 718 sheet and plate depends on thickness, final shape, load level and fabrication method. Sheet is used where forming, low weight and thin-section fabrication are important. Plate is used where machining, structural loading and thicker cross-sections are required.

Comparison	Inconel 718 Sheet	Inconel 718 Plate
Typical Use	Formed parts, hot-section sheet structures, seals and thin components	Machined blocks, turbine hardware, fixtures and structural parts
Key Buying Factor	Thickness tolerance, surface, forming condition and flatness	Plate thickness, UT, machining allowance and heat treatment
Processing Concern	Cracking during severe forming if condition is not suitable	Distortion, machining cost and internal soundness
Inspection Focus	Surface defects, thickness, flatness and mechanical properties	UT, dimensional inspection, hardness and heat-treatment verification

Aerospace Application Considerations

Aerospace applications usually require tighter control than general industrial orders. The material may need to meet an AMS specification, OEM drawing, purchase specification, approved mill source requirement or additional traceability rule.

✅ Confirm the exact AMS, ASTM, ASME or OEM specification.

✅ State solution treatment and aging condition clearly.

✅ Require full heat-number and production-lot traceability.

✅ Define tensile properties, hardness, grain size and inspection requirements.

✅ Request approved source or manufacturer documentation where required.

✅ Control surface defects, edge condition and packaging to prevent damage before machining or forming.

Turbine Application Considerations

Turbine components may experience high temperature, vibration, centrifugal load, thermal fatigue and oxidation. Inconel 718 sheet and plate are selected because they offer a strong balance of mechanical strength and temperature capability, but the final performance depends on heat treatment, surface quality and part design.

Turbine Requirement	Why It Matters	Material Check
High-Temperature Strength	Parts must resist deformation under heat and load	Heat-treatment condition and mechanical properties.
Fatigue Resistance	Vibration and thermal cycling can initiate cracks	Surface condition, defect control and design radius.
Oxidation Resistance	Hot gas exposure can degrade lower-alloy materials	Grade verification and surface cleanliness.
Dimensional Stability	Machined plate parts must remain within tolerance	Plate flatness, stress control and machining allowance.

Recommended Grades and Alternatives

Inconel 718 is a strong choice for high-strength aerospace and turbine applications, but it is not the only nickel alloy option. The final grade should be selected by service temperature, load, oxidation, corrosion, weldability and cost.

Material	When It May Be Selected	Main Limitation
Inconel 718	High-strength aerospace, turbine, cryogenic and fatigue-sensitive parts	Requires controlled heat treatment and is more difficult to machine than stainless steel.
Inconel 625	Corrosion-focused components, offshore service and weld overlays	Lower precipitation-hardened strength than 718 in typical conditions.
Inconel X-750	Springs, fasteners and high-temperature hardware	Application-specific heat treatment and property control are critical.
Incoloy 800H / 800HT	High-temperature furnace and petrochemical equipment	Not selected when very high strength like 718 is required.
Hastelloy X	Combustion-zone and hot-gas components requiring oxidation resistance	Strength and application profile differ from precipitation-hardened 718.

Heat Treatment and Condition Control

Inconel 718 properties depend strongly on solution treatment and aging. For aerospace and turbine applications, the ordered condition must be stated clearly because annealed, solution-treated and age-hardened material can have different strength, hardness, formability and machining behavior.

A complete inquiry should define whether the buyer needs material suitable for forming before final aging, finished aged material for machining or a condition controlled by a specific AMS or customer specification. Heat-treatment records may be required for critical orders.

✅ Confirm ordered condition before price comparison.

✅ State whether final aging will be done by the buyer or supplier.

✅ Review tensile, yield, elongation and hardness requirements for the final condition.

✅ Ask for heat-treatment chart or furnace record when required.

✅ Check whether the standard requires grain size, microstructure or additional testing.

Limitations and Processing Risks

Inconel 718 provides excellent performance, but buyers should understand its limitations before selecting it for every high-temperature component. It is more expensive and harder to machine than common stainless steels. Forming and welding require attention to condition, thickness, tooling and qualified procedures.

• It requires precise heat-treatment control to achieve target properties.

• Machining costs are higher because nickel alloys work-harden and require suitable tooling.

• Severe forming may require the correct annealed or solution-treated condition.

• Thick plate may require ultrasonic testing and machining allowance.

• Aerospace orders may require approved mills, special documentation and strict traceability.

• Grade substitution should not be accepted without engineering approval.

Standards, Certificates and Inspection

Inconel 718 sheet and plate may be purchased to ASTM B670 / ASME SB670, AMS specifications, customer specifications or aerospace OEM requirements. The standard should be confirmed before quotation because chemistry, condition, testing and documentation may differ.

Document or Test	What It Confirms
EN 10204 3.1 MTC	Heat number, chemistry, mechanical properties, standard and delivery condition.
AMS or Customer Certificate	Compliance with aerospace or customer-specific procurement requirements.
Heat-Treatment Record	Solution and aging cycle, temperature, hold time and batch traceability.
Dimensional Report	Thickness, width, length, flatness, tolerance and cut size.
Ultrasonic Testing	Internal soundness of plate or thick machined stock when required.
PMI Report	Alloy verification and material mix-up prevention.

How to Specify Inconel 718 Sheet Plate

A clear RFQ should include all technical and commercial details that affect price, production route and acceptance.

✅ Material: Inconel 718 / Alloy 718 / UNS N07718 / 2.4668.

✅ Product form: sheet, plate, strip, coil, cut plate or machined blank.

✅ Standard: ASTM B670 / ASME SB670, AMS or customer specification.

✅ Thickness, width, length, tolerance and quantity.

✅ Condition: solution annealed, annealed, aged or customer-specified heat treatment.

✅ Surface: mill, pickled, ground, polished or protected surface.

✅ Application: aerospace part, turbine component, spring, seal, fixture or machined structure.

✅ Testing: tensile, hardness, PMI, UT, dimensional inspection and surface inspection.

✅ Documentation: EN 10204 3.1, AMS certificate, third-party inspection or data book.

✅ Packaging, marking, destination port and required delivery date.

Common Buyer Mistakes

Ordering only “Inconel 718 plate”: This does not define standard, heat treatment, thickness tolerance, inspection or certificate requirements.

Ignoring condition: Annealed, solution-treated and age-hardened material can behave very differently during forming, machining and service.

Assuming ASTM and AMS requirements are interchangeable: Aerospace orders may require a specific AMS or OEM specification rather than a general industrial standard.

Skipping UT for thick plate: Internal soundness may be important for high-value machined turbine or aerospace components.

Comparing quotes without surface and cutting requirements: Mill finish, ground plate, precision cut blanks and protected surfaces can have different costs.

Not checking heat-number traceability: The MTC, plate marking, packing list and labels should match the supplied material.

Using the wrong grade for corrosion-focused service: Inconel 625 or Hastelloy alloys may be better when corrosion resistance is more important than precipitation-hardened strength.

FAQ

What is Inconel 718 sheet plate used for?

Inconel 718 sheet and plate are used for aerospace engine parts, turbine components, combustor structures, cryogenic hardware, springs, seals, high-strength brackets, machined plates and fabricated assemblies requiring strength and temperature resistance.

Why is Inconel 718 used in aerospace?

Inconel 718 provides high strength, fatigue resistance, oxidation resistance and good performance under elevated temperature and cyclic loading. These properties make it suitable for demanding aerospace and turbine-engine components.

What standard is used for Inconel 718 sheet and plate?

Inconel 718 sheet and plate are commonly specified to ASTM B670 / ASME SB670. Aerospace applications may require AMS or customer-specific specifications, so the exact standard should be confirmed before quotation.

Is Inconel 718 good for turbine applications?

Yes. Inconel 718 is widely used in turbine-related components because it combines high strength, fatigue resistance, oxidation resistance and elevated-temperature capability. Heat treatment and inspection requirements must be properly controlled.

What is the difference between Inconel 718 and Inconel 625?

Inconel 718 is a precipitation-hardening alloy selected mainly for high strength and fatigue performance. Inconel 625 is a solid-solution strengthened alloy often selected for corrosion resistance, seawater service and weld overlay applications.

Can Inconel 718 sheet be formed?

Yes, but formability depends on thickness, condition, bend radius, tooling and heat-treatment stage. Severe forming is usually easier before final aging. The forming plan should be reviewed before selecting the ordered condition.

What documents should be supplied with Inconel 718 sheet plate?

Typical documents include EN 10204 3.1 MTC, chemical composition, mechanical properties, heat number, product standard, dimensional report and heat-treatment information. Aerospace orders may also require AMS documentation, approved-source records or third-party inspection.

Related Nickel Alloy Products

Related Product	Procurement Use
Inconel 718 Product Range	Alloy 718 sheet, plate, bar, forging, pipe, tube and wire products for high-strength applications.
Inconel 718 Plate	Plate and cut stock for turbine parts, aerospace structures, fixtures and machined components.
Inconel 718 Round Bar	Round bar for fasteners, shafts, turbine hardware, aerospace parts and high-strength machined components.
Inconel 625 Products	Corrosion-resistant nickel alloy products for offshore, chemical and seawater environments.
Inconel 625 Bar for Offshore Components	Material-selection guidance for offshore corrosion, fatigue and subsea machined components.

Conclusion

Inconel 718 sheet plate is selected for aerospace, turbine, cryogenic and high-strength fabricated components because it combines precipitation-hardened strength, fatigue resistance, oxidation resistance and reliable performance under demanding service conditions. Sheet is typically used for formed and thin fabricated parts, while plate is selected for machined, structural and thicker high-load components.

For reliable procurement, buyers should define the exact standard, thickness, size, heat-treatment condition, surface finish, inspection scope, certification and application requirement. Aerospace and turbine applications should always confirm AMS, OEM or project-specific requirements before production.