Inconel 718 pipe is the pressure-containing product form of Alloy 718 (UNS N07718 / W. Nr. 2.4668), a precipitation-hardening nickel-chromium superalloy. It is specified when designers need high-temperature strength, oxidation resistance, and pressure integrity in the same component, conditions that push standard austenitic stainless steels beyond their limits.
The challenge for buyers is that “Inconel 718 pipe” covers several distinct specifications. A heat-exchanger designer needs ASTM B163 tubing with tight OD tolerances. An aerospace fuel-system engineer needs AMS 5589 seamless tubing with full traceability. An oil-and-gas project needs ASTM B983 pipe that can hold pressure in sour service. Each standard describes a different product with different testing, dimensional rules, and documentation requirements. Choosing the wrong one can delay qualification, raise cost, or create a leak path in a critical system.
This guide explains how to specify, size, and source Inconel 718 pipe for industrial, aerospace, and energy applications. For a broader technical overview of the alloy family, see our complete Inconel 718 technical guide.
Key Takeaways
- Inconel 718 pipe is available under ASTM B983 (seamless pipe), ASTM B163 (heat-exchanger tube), ASTM B516 (welded tube), and AMS 5589/5590 (aerospace tubing).
- Pipe is sized by nominal pipe size (NPS) and schedule; tube is sized by exact OD and wall thickness.
- Seamless pipe offers the highest pressure integrity and fatigue resistance; welded pipe is a cost-effective option for structural and lower-pressure service.
- Common OD range is 3 mm to 600 mm; wall thickness ranges from 0.5 mm to 100 mm depending on standard and process.
- Industrial-grade Inconel 718 pipe typically costs 30–30–65/kg in 2026; aerospace-certified material can exceed 75–75–100/kg.
- Zhonggongte supplies seamless and welded Inconel 718 pipe from Wuxi with ASTM, AMS, and GB certification and 24-hour RFQ response.
What Is Inconel 718 Pipe?
Material Grade and Equivalent Designations
Inconel 718 pipe is produced from the same alloy chemistry as Inconel 718 bar, plate, and forgings. The relevant designations are:
| System | Designation |
|---|---|
| UNS | N07718 |
| Werkstoff | 2.4668 |
| Trade name | Inconel 718, Alloy 718 |
| Chinese equivalent | GH4169 |
For buyers sourcing from Chinese mills, GH4169 is the direct metallurgical equivalent. The pipe form may be certified to GB/T 14992 or to ASTM/AMS if the mill is qualified for export production. For a detailed comparison of the grades, see our GH4169 equivalent Inconel 718 guide.
Pipe vs Tube: What Is the Difference?
The terms are often used interchangeably in supplier listings, but they have distinct engineering meanings.
| Feature | Pipe | Tube |
|---|---|---|
| Sizing basis | Nominal Pipe Size (NPS) and schedule | Exact outside diameter (OD) and wall thickness |
| Primary dimension | Inside diameter / flow area | Outside diameter and wall precision |
| Typical standards | ASTM B983, ASME SB983 | ASTM B163, ASTM B516, AMS 5589/5590 |
| Common use | Pressure piping, process lines, manifolds | Heat exchangers, condensers, instrumentation |
| Tolerance | Looser OD tolerance | Tighter OD and wall tolerance |
| Shapes | Usually round | Round, square, rectangular, coiled, U-bent |
If your drawing calls for NPS 2″ SCH 80, you are ordering pipe. If it calls for 50.8 mm OD × 3.0 mm wall, you are ordering tube. The wrong choice will not fit the fabrication or the pressure calculation.
Inconel 718 Pipe Specifications and Standards
ASTM B983 / ASME SB983, Seamless Pipe
ASTM B983 is the primary North American specification for seamless Inconel 718 pipe and tube. It covers UNS N07718 in the solution-annealed and aged conditions, with requirements for chemical analysis, mechanical testing, dimensions, tolerances, and non-destructive examination. This is the standard most oil-and-gas, chemical, and power projects reference when they need seamless pipe.
ASTM B163 / ASME SB163, Condenser and Heat-Exchanger Tubes
ASTM B163 covers seamless nickel and nickel-alloy tubes for condenser and heat-exchanger service. When an engineer specifies Inconel 718 pipe for a heat exchanger, they usually mean ASTM B163 tube with tight OD tolerances and often a bright annealed finish.
ASTM B516 / ASME SB516, Welded Tubes
ASTM B516 covers welded nickel-chromium-iron alloy tubes. It is the relevant standard for cost-sensitive applications where a welded construction is acceptable and the operating pressure or fatigue loading is moderate.
AMS 5589 / AMS 5590, Aerospace Tubing
AMS 5589 specifies seamless Alloy 718 tubing for aerospace applications. AMS 5590 is the welded-tube counterpart. These specifications add tighter chemistry, mechanical-property, and NDT requirements than ASTM standards. Aerospace buyers must state the exact AMS revision and any customer-specific tests.
DIN 17751 and Other International Standards
DIN 17751 covers nickel-alloy seamless tubes in Europe. For projects outside North America, buyers may see specifications referencing W. Nr. 2.4668 or EN 10095.
Chemical Composition of Inconel 718 Pipe
The chemistry of Inconel 718 pipe is identical to other product forms of the alloy. The niobium content drives the γ″ precipitation-hardening response that gives the material its high strength after aging.
| Element | UNS N07718 wt% |
|---|---|
| Nickel (Ni) | 50.0 – 55.0 |
| Chromium (Cr) | 17.0 – 21.0 |
| Iron (Fe) | Balance |
| Niobium + Tantalum (Nb+Ta) | 4.75 – 5.50 |
| Molybdenum (Mo) | 2.80 – 3.30 |
| Titanium (Ti) | 0.65 – 1.15 |
| Aluminum (Al) | 0.20 – 0.80 |
| Carbon (C) | ≤ 0.08 |
| Silicon (Si) | ≤ 0.35 |
| Manganese (Mn) | ≤ 0.35 |
| Phosphorus (P) | ≤ 0.015 |
| Sulfur (S) | ≤ 0.015 |
Every heat of pipe should ship with a material test report showing the actual chemistry. For critical applications, request a melt practice statement showing whether the material was air-melted, VIM+ESR, or VIM+VAR.
Mechanical Properties and Heat Treatment
Room Temperature Properties
| Condition | Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|---|
| Solution-annealed | ≥ 965 MPa | ≥ 550 MPa | ≥ 20% | ≤ 30 HRC |
| Aged | ≥ 1,240 MPa | ≥ 1,030 MPa | ≥ 12% | 36–44 HRC |
For a deeper look at how these properties change with condition and temperature, see our Inconel 718 mechanical properties reference.
Elevated Temperature Performance
Inconel 718 pipe retains useful strength up to about 650–700°C. Creep resistance and fatigue life depend on grain size, cleanliness, and the uniformity of the γ″ precipitate distribution. Aerospace and turbine applications almost always require VIM+ESR or VIM+VAR melt practice to achieve consistent elevated-temperature performance.
How Heat Treatment Affects Pipe Performance
The standard heat treatment is solution annealing followed by a two-step age:
- Solution anneal at 940–1,050°C, then air cool or water quench.
- First aging at 720°C for 8 hours, furnace cool to 620°C.
- Second aging at 620°C for 8 hours, then air cool.
This cycle produces the γ″/γ′ precipitate structure responsible for peak strength. For detailed cycle parameters, see our Inconel 718 heat treatment cycles guide.
Inconel 718 Pipe Sizes, Schedules, and Dimensions
Nominal Pipe Size and Schedule
Inconel 718 pipe follows ANSI/ASME B36.10M/B36.19M schedules. Common schedules include SCH 5, 10, 20, 30, 40, 80, 160, and XXH. The schedule determines wall thickness for a given NPS.
Common Size Range
| Parameter | Typical Range |
|---|---|
| Outer diameter | 3 mm – 600 mm (0.125″ – 24″) |
| Wall thickness | 0.5 mm – 100 mm |
| Length | Up to 12 meters, or cut to length |
| Schedules | SCH 5–XXH |
Sample Dimensions and Weights
| NPS | OD (mm) | Schedule | Wall (mm) | Weight (kg/m) |
|---|---|---|---|---|
| 1/2″ | 21.3 | SCH 40 | 2.77 | 1.27 |
| 3/4″ | 26.7 | SCH 40 | 2.87 | 1.69 |
| 1″ | 33.4 | SCH 40 | 3.38 | 2.50 |
| 2″ | 60.3 | SCH 40 | 3.91 | 5.44 |
| 3″ | 88.9 | SCH 40 | 5.49 | 11.29 |
| 4″ | 114.3 | SCH 40 | 6.02 | 16.07 |
| 6″ | 168.3 | SCH 40 | 7.11 | 28.26 |
Always confirm final dimensions and tolerances against the mill certificate or the specific ASTM/AMS specification. Custom sizes outside standard schedules are common for high-value alloy pipe.
Seamless vs Welded Inconel 718 Pipe
Manufacturing Difference
Seamless pipe starts from a solid billet that is pierced and then rolled or drawn to final dimensions. There is no longitudinal weld seam. Welded pipe is formed from strip or plate and joined by ERW, TIG, or plasma-arc welding.
Performance Comparison
| Feature | Seamless | Welded |
|---|---|---|
| Pressure integrity | Highest; no seam leak path | Good; seam requires inspection |
| Fatigue resistance | Superior | Lower than seamless |
| Corrosion resistance | Uniform; no HAZ | Weld zone may need treatment |
| Dimensional tolerance | Tight | Moderate |
| Lead time | Longer | Shorter |
| Cost | Higher | Lower |
| Common standards | ASTM B983, AMS 5589 | ASTM B516, AMS 5590 |
When to Choose Each
Choose seamless Inconel 718 pipe for:
- High-pressure manifolds and process piping
- Aerospace fuel, hydraulic, and pneumatic lines
- Downhole and subsea oil-and-gas components
- Cyclic loading or creep-resistant service
- Applications requiring hydrostatic or ultrasonic NDT with no seam variables
Choose welded Inconel 718 pipe for:
- Structural supports and frameworks
- Large-diameter, low-to-moderate pressure ducting
- Cost-sensitive projects with qualified welding procedures
- Applications where post-weld heat treatment can be performed and verified
Manufacturing Process: How Inconel 718 Seamless Pipe Is Made
Billet Preparation
Production begins with a solid Inconel 718 billet. For critical applications, the billet is double-melted or triple-melted, typically VIM (vacuum induction melting) followed by ESR (electroslag remelting) or VAR (vacuum arc remelting). This reduces inclusions and improves cleanliness.
Piercing and Hot Extrusion
The billet is heated and pierced to form a hollow shell. The shell is then rolled or extruded to reduce wall thickness and increase length. This hot-working stage establishes the basic pipe geometry.
Cold Drawing or Pilgering
To achieve precise dimensions and improved surface finish, the hollow shell is cold-drawn or pilgered. Cold work also improves mechanical properties, but it must be followed by controlled heat treatment to relieve stress and achieve the desired condition.
Heat Treatment and Finishing
The pipe is solution-annealed, aged if required, straightened, cut to length, pickled, and polished. Finishing may include bright annealing for tubing used in heat exchangers.
Testing
Common tests include:
- Hydrostatic pressure test
- Ultrasonic testing (UT)
- Eddy-current testing
- Dimensional and visual inspection
- Chemical analysis by OES
- Mechanical testing (tensile, hardness)
Applications of Inconel 718 Pipe
Aerospace and Gas Turbines
AMS 5589 seamless tubing is used in fuel manifolds, hydraulic lines, bleed-air ducts, and rocket propellant lines. The combination of high strength-to-weight ratio and oxidation resistance makes it essential for hot-section components.
Oil and Gas Downhole and Subsea
ASTM B983 pipe resists sour-gas corrosion, chloride stress-corrosion cracking, and high-pressure environments. Typical uses include downhole tools, wellhead components, subsea valves, and high-pressure flowlines.
Chemical and Petrochemical Processing
Heat exchangers, catalytic reactors, and furnace tubes use ASTM B163 tubing where oxidation and process-media corrosion are concerns. The alloy’s resistance to pitting and crevice corrosion extends service life compared to standard stainless steels.
Nuclear and Power Generation
Inconel 718 pipe and tube are used in reactor cooling systems, fuel-element spacers, and high-temperature instrumentation where creep resistance and dimensional stability matter.
Inconel 718 Pipe Price Per Kg
Current Price Range (2026)
| Grade / Specification | Approximate Price (USD/kg) |
|---|---|
| Standard industrial seamless pipe (ASTM B983) | 30–30–65 |
| Welded pipe / tube (ASTM B516) | 25–25–50 |
| Aerospace seamless tubing (AMS 5589) | 75–75–120+ |
| Large-diameter or heavy-wall custom pipe | 60–60–150+ |
For broader pricing context across all product forms, see our Inconel 718 price per kg guide.
Factors Affecting Price
- Form: Seamless costs more than welded.
- Specification: AMS/Aerospace commands a premium over ASTM industrial grades.
- Size and wall thickness: Heavy-wall and large-OD pipe require more material and processing.
- Quantity: Mill minimum-order quantities and setup costs affect per-kg price.
- Certification: EN 10204 3.2, third-party inspection, and NDT add cost.
- Nickel market: LME nickel volatility directly affects alloy surcharge.
- Origin: Chinese mills are typically 15–25% lower than Western-branded material for equivalent specifications.
How to Source Inconel 718 Pipe from China
What to Specify in Your RFQ
A complete RFQ for Inconel 718 pipe should include:
- Alloy and UNS number: Inconel 718 / UNS N07718
- Standard: ASTM B983, B163, B516, AMS 5589/5590, or GB/T 14992
- Condition: Solution-annealed or aged
- Product form: Seamless or welded
- Dimensions: NPS/schedule or exact OD × wall × length
- Quantity: Weight or number of pieces
- Surface finish: Pickled, polished, bright annealed
- Ends: Plain, beveled, threaded
- Certification: MTR, EN 10204 3.1/3.2, NDT
- End use or application
- Delivery terms and destination
Supplier Qualification Checklist
- Can the supplier document VIM+ESR or VIM+VAR melt practice?
- Is in-house OES spectrometry available for every heat?
- Are mechanical, hardness, and NDT tests performed in-house or by approved labs?
- Does the supplier hold ISO 9001, AS9100, or NADCAP approvals if required?
- Can the supplier provide EN 10204 3.1/3.2 certificates?
- Is there experience exporting to your region with full customs documentation?
- Can the supplier trace each heat from melt to final inspection?
Documentation Requirements
At minimum, request:
- Mill Test Report (MTR) with heat number and chemistry
- Mechanical test report for the ordered condition
- Heat treatment chart
- Melt practice statement
- EN 10204 3.1 or 3.2 certificate
- NDT reports if specified
Zhonggongte Inconel 718 Pipe Capability
Jiangsu Zhonggongte Metallurgical Technology Co., Ltd. supplies Inconel 718 pipe and tube from Wuxi in seamless and welded construction. Available standards include ASTM B983, ASTM B163, ASTM B516, AMS 5589/5590, and GB/T 14992 / GJB 2611A. Our production routes include vacuum induction melting and electroslag remelting, supported by in-house direct-reading spectrometers, tensile testing, hardness testing, hydrostatic testing, and ultrasonic NDT.
We also supply related product forms, including Inconel 718 round bar, plate, sheet, and forgings. Every order ships with a material test report, and we can provide EN 10204 3.1/3.2 certification and third-party inspection on request.
Our metallurgical engineers review each RFQ to confirm that the proposed pipe specification, condition, melt practice, and certification match the application. Submit your specification and we will respond within 24 hours with availability, pricing, and a clear certification pathway.
Conclusion
Inconel 718 pipe is not a one-size-fits-all product. The right choice depends on whether the application needs pipe or tube, seamless or welded construction, ASTM or AMS certification, and solution-annealed or aged mechanical properties. Buyers who specify only the alloy grade risk receiving material that meets chemistry but fails the dimensional, testing, or documentation requirements of their project.
For general industrial piping, ASTM B983 seamless pipe is the most common starting point. For heat exchangers, specify ASTM B163 tubing with the right OD tolerance and finish. For aerospace, specify AMS 5589 with full traceability and NDT. For structural or budget-sensitive projects, welded pipe under ASTM B516 can be a sound alternative when the welding and heat treatment are properly qualified.
Zhonggongte manufactures and supplies certified Inconel 718 pipe from Wuxi with VIM/ESR capability, in-house spectral verification, and full export documentation. Whether your drawing calls out ASTM B983, B163, AMS 5589, or GB/T 14992, our team will confirm the certification pathway and deliver a quote within 24 hours.
