In aircraft engine fuel systems and high-pressure hydraulic actuators, piping is a lifeline. For purchasing managers and engineers, key pain points when sourcing GH4169 seamless steel pipe include:
Inconsistent wall thickness (poor concentricity): Uneven wall thickness creates localized "thin spots," which can fail under high circumferential stress, leading to pipe bursts and catastrophic consequences.
Internal oxidation and impurities: Standard annealing processes leave oxide scale inside the pipe. At high flow rates, these impurities can detach and clog sensitive fuel injectors and sensors.
At Gnee Alloy, we eliminate these risks. As a dedicated Tier-1 manufacturer, Gnee Alloy provides zero-defect piping designed to ensure absolute structural integrity.
Click to get a GH4169 product quote
GH4169 (Inconel 718) High Pressure Seamless Steel Pipe Procurement Guide
Gnee Alloy
GH4169 (Inconel 718) High Pressure Seamless Steel Pipe Procurement Guide
GH4169 (Inconel 718) seamless steel pipe is a high-strength, corrosion-resistant nickel-chromium-based alloy pipe designed for extreme environments. Operating at temperatures up to 700°C (1300°F), it is crucial in aerospace engines, nuclear engineering, and high-pressure oil and gas applications, and exhibits excellent fatigue and oxidation resistance.
Gnee Alloy
What are the uses of Inconel 718?
Inconel 718 is one of the most commonly used alloys in metal additive manufacturing (MAM), widely used in aircraft, gas turbines, turbocharger rotors, and a variety of other corrosive and structural applications, with a maximum operating temperature of approximately 700 °C.
1. Overview and Scope of GH4169 (Inconel 718) Seamless Steel Pipe Products
| Parameter | Description |
|---|---|
| Material | GH4169 (UNS N07718 / Inconel 718) |
| Product Form | High Pressure Seamless Tube |
| Manufacturing Process | Cold Drawn / Cold Pilgered |
| Surface Condition | Annealed & Pickled (AP) / Bright Annealed (BA) |
| Applicable Standards | AMS 5589, AMS 5590, ASTM B983, GB/T 14994 |
| Typical Applications | Aircraft engine high pressure hydraulic lines, fuel manifolds, bleed air ducts, turbine cooling lines, rocket engine high pressure lines |
| Maximum Service Temperature | 650 – 700°C (load-bearing) |
2. Chemical composition of GH4169 (Inconel 718) seamless steel pipe (wt%)
| Element | Content (%) | Function |
|---|---|---|
| Nickel (Ni) | 50.0 – 55.0 | Matrix element; high-temperature stability |
| Chromium (Cr) | 17.0 – 21.0 | Oxidation and corrosion resistance |
| Iron (Fe) | Balance (~18-20) | Fe-Ni-Cr base alloy |
| Niobium (Nb) | 4.75 – 5.50 | Core strengthening element – forms γ″ phase (Ni₃Nb) |
| Molybdenum (Mo) | 2.80 – 3.30 | Solid-solution strengthening; creep and pitting resistance |
| Titanium (Ti) | 0.65 – 1.15 | Forms γ′ strengthening phase |
| Aluminum (Al) | 0.20 – 0.80 | Forms γ′ strengthening phase; improves oxidation resistance |
| Carbon (C) | ≤ 0.08 | Low carbon for weldability and toughness |
| Manganese (Mn) | ≤ 0.35 | Deoxidizer |
| Silicon (Si) | ≤ 0.35 | Deoxidizer |
| Phosphorus (P) | ≤ 0.015 | Ensures toughness |
| Sulfur (S) | ≤ 0.015 | Ensures hot workability |
| Boron (B) | 0.002 – 0.006 | Grain boundary strengthener; improves stress rupture life |
| Cobalt (Co) | ≤ 1.00 | Residual element |
| Copper (Cu) | ≤ 0.30 | Residual element |
Click to download the GH4169 alloy PDF file now
3. Mechanical properties of GH4169 pipe at 650°C (1200°F)
| Property | Value (Fully Aged) | Why it Matters |
| Yield Strength (σp0.2) | ≥ 850 MPa | Prevents deformation under load. |
| Tensile Strength (σb) | ≥ 1000 MPa | Elite high-pressure safety factor. |
| Elongation (δ5) | ≥ 15% | High toughness at extreme heat. |
| Stress Rupture Life | ≥ 100h at 690 MPa | Guaranteed Long-term Service Life. |
4. GH4169 pipe size and surface quality standards
| Parameter | Manufacturing Capability | Commercial Advantage |
| Tolerance Class | h8, h9, h10 | Perfect fit for precision fittings. |
| Surface Finish | Bright Annealed (BA) | Mirror ID/OD (Ra ≤ 0.4μm). |
| Internal Cleanliness | Zero Oxidation Scale | Protects sensitive sensors & injectors. |
| Straightness | ≤ 0.5 mm / meter | Optimized for high-speed CNC assembly. |
5. Manufacturing and Quality Requirements for GH4169 High-Pressure Seamless Tubes
To ensure the reliability of high-pressure systems, the following requirements must be met:
Process: Seamless cold drawing or hot rolling (usually followed by precision rolling/Pilger rolling).
Surface Treatment: Bright annealing, polishing, or pickling to remove surface defects.
Testing:
Hydrostatic testing: A prerequisite for high-pressure certification.
Non-Destructive Testing (NDT): Ultrasonic and eddy current testing to ensure the absence of internal defects.
Traceability: Furnace number tracing is crucial.
6. Application Areas of GH4169 Seamless Steel Tubes
Aerospace: Aircraft engine components and rocket engine components.
Oil & Gas: Wellhead components, downhole tools, and high-pressure fluid transport.
Energy: Nuclear power components and heat exchangers.
7. 2026 Procurement and Market Insights
Price Trends: Global seamless steel pipe prices are expected to rise moderately by mid-2026, with high-end nickel-based alloys (such as Inconel 718) being significantly affected by raw material price fluctuations.
Delivery Time: Delivery times may be extended due to high demand from the energy sector and specific manufacturing processes (e.g., consumable remelting).
Documents: If needed, click to obtain the 3.1 or 3.2 Material Testing Certificate (MTC) to ensure compliance with the NACE MR-0175 acidic environment standard.
Gnee Steel GH4169(inconel 718) Certificate
📦 Packaging and Shipping
All Nickel Based Alloy products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel GH4169 Product Packing
Contact us for the latest export price quote for GH4169 Alloy
FAQ
Q1: Is GH4169 technically identical to Inconel 718 tubing?
A: Yes. GH4169 is the technische designation used in Chinese national standards (GB/T) for the metallurgical system known globally as Inconel 718 (UNS N07718). They are globally interchangeable.
Q2: What is the benefit of the Bright Annealed (BA) finish?
A: Unlike pickled pipes, Bright Annealed pipes are heat-treated in a high-purity hydrogen atmosphere. This results in a mirror-bright surface that is free of oxidation, which is essential for "Oxygen Clean" or high-purity fluid transport.
Q3: Can you produce non-standard thin-wall or heavy-wall pipes?
A: Absolutely. We specialize in Custom Fabrication and can produce seamless tubing to your exact ID/OD and wall thickness requirements, with tolerances as tight as ±0.02mm.
Q4: Do you offer wholesale pricing for annual supply contracts?
A: Yes. As a direct Tier-1 Manufacturer, we provide tiered Wholesale Pricing and dedicated inventory reserves for our long-term OEM and MRO partners.
