A common and costly mistake in the field of high-temperature alloys is choosing materials solely based on price or a good reputation for "high-temperature" performance, neglecting the analysis of mechanical loads.
Pain Point: Many engineers choose Inconel 625 for high-pressure fuel lines or rotating components because of its excellent corrosion resistance, only to find that the pipes deform or burst under load at 650°C. Conversely, using GH4169 (718) in strong acid environments does not result in a wasted budget, as its corrosion rate may be faster than 625.
Choosing the right nickel-based seamless alloy tubing requires striking a balance between structural integrity and industrial durability. At Gnee Steel, we offer data-driven engineering support to help you solve this problem.
Contact us for GH4169 seamless steel pipe selection
Comparison of corrosion resistance between GH4169 and Inconel 625 seamless steel pipes
Comparison of corrosion resistance between GH4169 and Inconel 625 seamless steel pipes
Compared to GH4169 (a Chinese-made Inconel 718 alloy) seamless pipe, Inconel 625 pipe generally exhibits superior corrosion resistance, especially in high-chloride, marine, and acidic environments. While both are high-performance nickel-based alloys used for seamless steel pipes, the higher chromium and molybdenum content of Inconel 625 pipe makes it better resistant to pitting corrosion, crevice corrosion, and oxidizing media.
What are the disadvantages of Inconel 718?
Disadvantages and alternatives of Inconel 718
While Inconel 718 boasts excellent mechanical and corrosion resistance properties, it also has some drawbacks: High cost: Due to its complex manufacturing process, Inconel 718 is expensive. Difficult to process: Its high hardness makes material removal difficult and accelerates tool wear.
Information on GH4169 and Inconel 625 seamless tubing
GH4169 (718 alloy) seamless tube
GH4169 is a precipitation-hardened superalloy. Its "superpower" comes from the γ ′′ (Gamma Double Prime) phase, which makes it one of the strongest metals available for service up to 700°C.
Primary Advantage: Elite Mechanical Load capacity. It maintains stiffness and resists creep under extreme pressure.
Strengthening Method: Precipitation hardening (Niobium-based).
Best For: Aerospace turbine engine parts, high-pressure fuel lines, and high-strength fasteners.
Inconel 625 (UNS N06625) Alloy Pipe
Inconel 625 is a solid-solution strengthened alloy. It doesn't rely on heat treatment for its properties but on the interaction between Molybdenum and Niobium in its nickel-chromium matrix.
Primary Advantage: Superior Pitting & Crevice Corrosion Resistance. It is almost immune to chloride-ion stress corrosion cracking.
Best For: Chemical processing reactors, offshore oil platforms, and flue gas desulfurization systems.
Strengthening Method: Solid solution strengthening.
3. Chemical composition (wt%) of GH4169 and Inconel 625 seamless tubing
| Element | GH4169 (Inconel 718) | Inconel 625 | Key Difference |
|---|---|---|---|
| Nickel (Ni) | 50.0 – 55.0 | 58.0 min (Balance) | 625 has higher Ni |
| Chromium (Cr) | 17.0 – 21.0 | 20.0 – 23.0 | 625 higher |
| Iron (Fe) | Balance (~18-20) | ≤ 5.0 | GH4169 much higher Fe |
| Molybdenum (Mo) | 2.80 – 3.30 | 8.0 – 10.0 | 625 has 3x more Mo |
| Niobium (Nb) | 4.75 – 5.50 | 3.15 – 4.15 | GH4169 higher |
| Titanium (Ti) | 0.65 – 1.15 | ≤ 0.40 | GH4169 higher |
| Aluminum (Al) | 0.20 – 0.80 | ≤ 0.40 | GH4169 higher |
| Cobalt (Co) | ≤ 1.00 | ≤ 1.0 | Similar |
| Carbon (C) | ≤ 0.08 | ≤ 0.10 | Similar |
| Manganese (Mn) | ≤ 0.35 | ≤ 0.50 | Similar |
| Silicon (Si) | ≤ 0.35 | ≤ 0.50 | Similar |
| Phosphorus (P) | ≤ 0.015 | ≤ 0.015 | Similar |
| Sulfur (S) | ≤ 0.015 | ≤ 0.015 | Similar |
| Boron (B) | ≤ 0.006 | – | GH4169 unique |
Click to download the GH4169 alloy PDF file now
4. Physical Properties of GH4169 and Inconel 625 Seamless Tubes
| Property | GH4169 (718) | Inconel 625 |
|---|---|---|
| Density | 8.19 g/cm³ | 8.44 g/cm³ |
| Melting Range | 1260 – 1336°C | 1290 – 1350°C |
| Thermal Conductivity (20°C) | 11.4 W/m·K | 9.8 W/m·K |
| Coefficient of Thermal Expansion (20-100°C) | 13.0 × 10⁻⁶/°C | 12.8 × 10⁻⁶/°C |
| Specific Heat (20°C) | 435 J/kg·K | 410 J/kg·K |
| Electrical Resistivity | 1.25 µΩ·m | 1.29 µΩ·m |
| Magnetic Properties | Slightly magnetic | Non-magnetic |
5. Comparison of corrosion resistance between GH4169 and Inconel 625 seamless pipes
| Environment | GH4169 (Inconel 718) | Inconel 625 |
|---|---|---|
| Oxidizing Acids (HNO₃) | Good | Excellent |
| Reducing Acids (HCl, H₂SO₄) | Poor to Fair | Excellent (due to high Mo) |
| Chloride Pitting Resistance | Moderate | Excellent (high Mo + Nb) |
| Chloride Crevice Corrosion | Moderate | Excellent |
| Chloride Stress Corrosion Cracking (SCC) | Good (high Ni) | Excellent |
| Seawater | Limited | Excellent |
| Sour Gas (H₂S/CO₂) | Good (with proper HT) | Excellent |
| High-Temperature Oxidation (up to 980°C) | Good | Excellent |
| Sulfidation | Moderate | Excellent |
Corrosion Resistance Rating (1-5, 5 = best)
| Environment | GH4169 (718) | Inconel 625 |
|---|---|---|
| Nitric Acid | 4 | 5 |
| Sulfuric Acid (dilute) | 2 | 5 |
| Hydrochloric Acid (dilute) | 1 | 4 |
| Phosphoric Acid | 3 | 5 |
| Seawater | 2 | 5 |
| Chloride SCC | 4 | 5 |
| High-Temperature Oxidation | 4 | 5 |
4. How to choose between GH4169 and Inconel 625 seamless tubing?
Order GH4169 Seamless Pipes if: Your application involves high internal pressure, centrifugal forces (rotating parts), or needs to maintain tight dimensional tolerances under stress at 650°C. It is the most Cost-effective Solution for high-load aerospace and energy projects.
Order Inconel 625 Seamless Pipes if: Your piping system is exposed to seawater, phosphoric acid, or hot contaminated media where Pitting and Crevice Corrosion are the primary failure modes. It offers the best Industrial Durability for the chemical and marine industries.
Request today's GH4169 price comparison and inventory list
5. Why source GH4169 seamless tubing from a top-tier high-temperature alloy manufacturer like Gnee Steel?
Whether you need the strength of GH4169 or the resistance of 625, we ensure Zero-Defect quality:
✅️VIM + VAR Melting: Our dual-vacuum refining process eliminates inclusions, ensuring superior fatigue life for both grades.
✅️MTC 3.1 Traceability: Every pipe is delivered with a full EN 10204 3.1 certificate documenting heat analysis and mechanical verification.
✅️Wholesale Inventory: Large stock of standard schedules (Sch 40, Sch 80) ready for Fast Global Shipping.
✅️Custom Fabrication: We provide precision cutting, centerless grinding (h8-h11), and custom bending services.
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: Can GH4169 replace Inconel 625 in offshore applications?
A: Only if strength is the priority. For seawater exposure, Inconel 625 is vastly superior. GH4169 may suffer from localized pitting if the surface is not specifically protected.
Q2: Which alloy is more expensive?
A: Generally, GH4169 is more expensive per kg due to the complex multi-stage precipitation heat treatment (Aging) and higher Niobium content required to achieve its elite strength.
Q3: Is GH4169 suitable for high-pressure hydrogen storage?
A: Yes, GH4169 has better resistance to hydrogen embrittlement than many high-strength steels, though Inconel 625 is also frequently used in hydrogen service where lower pressures are involved.
Q4: Do you offer trial orders for small batch fabrication?
A: Absolutely. We support prototype development and offer Flexible MOQs for both GH4169 and Inconel 625 seamless tubing.
