GH4169 (Alloy 718) vs. Alloy 28 (UNS N08028): Performance Comparison Guide
GH4169 (Chinese standard, i.e., Inconel 718, UNS N07718) and Alloy 28 (UNS N08028) are both high-performance nickel-based alloys designed for extreme environments, but their primary applications differ. GH4169 is a precipitation-hardening superalloy designed for high-temperature strength and fatigue resistance (aerospace/turbines), while Alloy 28 is a corrosion-resistant alloy focused on superior corrosion resistance in acidic, sulfur-containing oilfield environments (high-temperature, high-pressure downhole tubing).
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.
1. Comparison of chemical composition of GH4169 and Alloy 28 (wt%)
| Element | GH4169 (Inconel 718) | Alloy 28 | Key Difference |
|---|---|---|---|
| Nickel (Ni) | 50.0 – 55.0 | 29.0 – 32.0 | GH4169 has higher Ni |
| Chromium (Cr) | 17.0 – 21.0 | 26.0 – 28.0 | Alloy 28 has higher Cr |
| Iron (Fe) | Balance (~18-20) | Balance (~35-40) | Alloy 28 has higher Fe |
| Molybdenum (Mo) | 2.80 – 3.30 | 3.0 – 4.0 | Alloy 28 slightly higher |
| Niobium (Nb) | 4.75 – 5.50 | – | GH4169 contains Nb |
| Titanium (Ti) | 0.65 – 1.15 | – | GH4169 contains Ti |
| Aluminum (Al) | 0.20 – 0.80 | – | GH4169 contains Al |
| Copper (Cu) | ≤ 0.30 | 0.6 – 1.4 | Alloy 28 contains Cu |
| Carbon (C) | ≤ 0.08 | ≤ 0.03 | Alloy 28 lower C |
| Manganese (Mn) | ≤ 0.35 | ≤ 2.0 | Alloy 28 higher |
| Silicon (Si) | ≤ 0.35 | ≤ 1.0 | Alloy 28 higher |
| Phosphorus (P) | ≤ 0.015 | ≤ 0.030 | – |
| Sulfur (S) | ≤ 0.015 | ≤ 0.010 | – |
| Boron (B) | 0.002 – 0.006 | – | GH4169 contains B |
| Cobalt (Co) | ≤ 1.00 | – | – |
| Nitrogen (N) | – | ≤ 0.10 | Alloy 28 contains N |
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2. Comparison of room temperature mechanical properties of GH4169 and Alloy 28
| Property | GH4169 (718) (Aged) | Alloy 28 (Annealed) | Advantage |
|---|---|---|---|
| Tensile Strength, Ultimate (MPa) | ≥ 1275 (185 ksi) | ≥ 500 – 600 (73-87 ksi) | GH4169 (~120% higher) |
| Tensile Strength, Yield (MPa) | ≥ 1035 (150 ksi) | ≥ 220 – 280 (32-40 ksi) | GH4169 (~320% higher) |
| Elongation (%) | ≥ 12 | ≥ 35 – 45 | Alloy 28 |
| Reduction of Area (%) | ≥ 15 | ≥ 50 | Alloy 28 |
| Hardness | 35 – 40 HRC | ~90 HRB (~18 HRC) | GH4169 |
| Modulus of Elasticity (GPa) | ~200 | ~195 | Similar |
| Density (g/cm³) | 8.19 | 8.00 | GH4169 slightly heavier |
3. Comparison of high-temperature mechanical properties of GH4169 and Alloy 28
| Temp (°C) | Property | GH4169 (718) | Alloy 28 |
|---|---|---|---|
| 500 | Tensile (MPa) | ~1150 | ~450 |
| Yield (MPa) | ~950 | ~180 | |
| 600 | Tensile (MPa) | ~1100 | ~380 |
| Yield (MPa) | ~900 | ~160 | |
| 650 | Tensile (MPa) | ~1000 | ~320 |
| Yield (MPa) | ~850 | ~140 | |
| 700 | Tensile (MPa) | ~850 | ~260 |
| Yield (MPa) | ~750 | ~120 | |
| 800 | Tensile (MPa) | ~500 | ~150 |
| Yield (MPa) | ~450 | ~80 |
High-Temperature Strength Retention:
| Temperature | GH4169 Retention | Alloy 28 Retention |
|---|---|---|
| 500°C | ~90% | ~80% |
| 600°C | ~86% | ~68% |
| 700°C | ~65% | ~46% |
summary：
GH4169/718: Exhibits excellent tensile strength, creep strength, and fatigue strength at high temperatures (up to 650°C, and even higher under certain conditions). Its strength can be maintained through heat treatment (precipitation hardening), making it ideal for rotating machinery such as turbine blades and rocket components. Furthermore, it exhibits excellent toughness at low temperatures.
Alloy 28: Designed to achieve high strength at approximately 175°C (350°F), suitable for downhole equipment. While it has high strength, its high-temperature creep strength is not as good as GH4169/718.
Contact our professionals to recommend the right alloy for your project
4. Comparison of corrosion resistance between GH4169 and Alloy 28
| Environment | GH4169 (718) | Alloy 28 | Advantage |
|---|---|---|---|
| General Atmospheric | Excellent | Excellent | Similar |
| Oxidizing Acids (HNO₃) | Good | Excellent | Alloy 28 |
| Reducing Acids (H₂SO₄, HCl) | Poor | Excellent | Alloy 28 |
| Phosphoric Acid | Good | Excellent | Alloy 28 |
| Chloride Pitting | Moderate | Excellent | Alloy 28 |
| Chloride SCC | Good (high Ni) | Excellent | Alloy 28 |
| Seawater | Limited | Excellent | Alloy 28 |
| Sour Gas (H₂S/CO₂) | Good (with proper HT) | Excellent | Alloy 28 |
| High-Temperature Oxidation | Good to 980°C | Moderate to 500°C | GH4169 |
Corrosion Resistance Summary
Alloy 28: Superior to GH4169 in high hydrogen sulfide (H₂S) and high chloride environments. It is specifically designed to resist pitting and stress corrosion cracking in deep, high-pressure, high-temperature (HPHT) acidic gas wells. It exhibits high resistance to sulfuric acid and phosphoric acid.
GH4169/718: Exhibits excellent corrosion resistance and oxidation resistance at high temperatures, making it highly useful in aerospace exhaust environments. However, it is not optimized for extreme chloride-containing acidic aqueous solutions like Alloy 28.
Contact us to customize GH4169 products to fit your project dimensions
5. GH4169 and Alloy 28 Industrial Applications
GH4169 (Inconel 718) is suitable for: aircraft engine components, gas turbine engines, rockets, nuclear reactor components, and fasteners-applications requiring extremely high structural integrity at high temperatures.
Alloy 28 (UNS N08028) is suitable for: underground equipment in oil and gas production tubing (OCTG), packers, high-pressure high-temperature (HPHT) sour oil wells, and acid gas injection (AGI) wells. It is also used in chemical processing, heat exchangers, and marine environments.
6. Summary of Differences Between GH4169 and Alloy 28 Selection
If you require high strength at temperatures above 500°C: Select GH4169/718
If you require high strength in H,S/chloride environments at temperatures below 200°C: Select Alloy 28.
Why choose Gnee Alloy, a Tier 1 global supplier?
As a professional superalloy manufacturer, Gnee Alloy offers more than just raw materials:
✅️Zero Inclusion Guarantee: Our VIM+VAR process eliminates inclusions that cause premature fatigue failure in energy projects.
✅️Total Traceability: Every order is delivered with an EN 10204 3.1 Mill Test Certificate (MTC) and heat-number tracking.
✅️Wholesale Pricing: Benefit from Direct Factory Price on bulk tonnage for offshore infrastructure.
✅️Custom Fabrication: We offer precision cutting, centerless grinding, and custom bending to match your assembly blueprints.
Contact us now to get the latest export price for GH4169 in 2026
FAQ
Q1: Can GH4169 replace Alloy 28 in production tubing?
A: Theoretically yes, but it is not Cost-effective. GH4169 is significantly more expensive. For long runs of tubing where strength is secondary to corrosion, Alloy 28 is the industry standard.
Q2: Does your GH4169 material strictly meet NACE MR0175?
A: Yes. For energy orders, we follow specialized solution and aging protocols to keep the hardness within the NACE limits (typically ≤ 40 HRC), ensuring the material is resistant to sulfide stress cracking.
Q3: Which alloy has a better material life cycle in high-chloride brine?
A: Alloy 28 is specifically designed for chloride environments. While GH4169 is resistant, Alloy 28's high Chromium and Molybdenum content make it more stable against pitting over decades of service.
Q4: Do you support small trial orders for offshore pilots?
A: Absolutely. We support innovation in the energy sector. We offer Flexible MOQs for standard sizes in our Wholesale Inventory.
