GH4169 and Inconel 718 (UNS N07718) are two of the most widely used precipitation-hardening nickel-based superalloys in the world. GH4169 is the Chinese designation per GB/T 14992, while Inconel 718 is the Western brand name developed by Special Metals Corporation. Although they are chemically nearly identical and share the same gamma double-prime (Ni&sub3;Nb) strengthening mechanism, there are important differences in standard compliance, certification, supply chain, and pricing.
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What Is GH4169?
GH4169 is a precipitation-strengthened nickel-iron-chromium alloy with niobium and molybdenum additions, designated under the Chinese national standard GB/T 14992. The "GH" prefix stands for "high-temperature alloy" in Chinese material nomenclature. GH4169 was developed in China as an equivalent to Inconel 718, optimized for aerospace, nuclear, and petrochemical applications within the domestic supply chain.
The alloy conforms to GB/T 14992 (classification and designation), GB/T 14993 (forging), GB/T 14994 (bar), GB/T 15062 (plate), and HB 5312 (aerospace standard). Its primary strengthening mechanism is the precipitation of gamma double-prime (γ'') phase Ni&sub3;Nb during age hardening, providing excellent high-temperature strength up to 650°C and good creep resistance up to 700°C.
What Is Inconel 718?
Inconel 718 (UNS N07718, W.Nr.2.4668, DIN NiCr19Fe19Nb5Mo3) is a precipitation-hardening nickel-iron-chromium alloy developed by Special Metals Corporation. It is the most widely used superalloy in the global aerospace industry, accounting for over 30% of total superalloy production by weight and found in virtually every modern gas turbine engine.
Inconel 718 conforms to ASTM B637 (bar), ASTM B670 (plate/sheet), AMS 5662 (bar), AMS 5596 (sheet), and AMS 5663 (forging). It is valued for its exceptional combination of high strength, good fatigue resistance, excellent weldability, and corrosion resistance from cryogenic temperatures up to 700°C. Is Inconel a nickel alloy? Yes - Inconel 718 contains 50–55% nickel, making it a true nickel-based superalloy.
GH4169 vs Inconel 718: Chemical Composition Comparison
The GH4169 chemical composition is essentially identical to Inconel 718 chemical composition, with only minor differences in specification ranges. Both alloys are based on Ni-Cr-Fe with Nb, Mo, Ti, and Al additions for precipitation hardening. The table below shows the side-by-side comparison:
| Element | GH4169 (GB/T 14992) | Inconel 718 (ASTM B637) | Difference |
|---|---|---|---|
| Ni | 50.0 – 55.0 | 50.0 – 55.0 | None |
| Cr | 17.0 – 21.0 | 17.0 – 21.0 | None |
| Fe | Balance | Balance | None |
| Nb + Ta | 4.75 – 5.50 | 4.75 – 5.50 | None |
| Mo | 2.80 – 3.30 | 2.80 – 3.30 | None |
| Ti | 0.65 – 1.15 | 0.65 – 1.15 | None |
| Al | 0.35 – 0.80 | 0.20 – 0.80 | GH4169: min Al higher |
| Co | ≤1.00 | ≤1.00 | None |
| C | ≤0.08 | ≤0.08 | None |
| Mn | ≤0.35 | ≤0.35 | None |
| Si | ≤0.35 | ≤0.35 | None |
| B | ≤0.006 | ≤0.006 | None |
| P | ≤0.015 | ≤0.015 | None |
| S | ≤0.015 | ≤0.015 | None |
The bottom line: GH4169 and Inconel 718 share nearly identical chemical specifications. The only minor variance is in the aluminum minimum (0.35% in GH4169 vs 0.20% in ASTM B637), but in practice, both alloys are produced with Al in the 0.4–0.7% range, making them functionally interchangeable. The difference between incoloy and inconel is more significant (nickel content), whereas GH4169 vs 718 is essentially the same alloy under different naming systems.
GH4169 vs Inconel 718: Mechanical Properties Comparison
Both alloys achieve their high strength through double aging heat treatment, producing gamma double-prime (γ'') Ni&sub3;Nb precipitates. The mechanical property requirements are nearly identical:
| Property | GH4169 (Aged) | Inconel 718 (Aged) | Difference |
|---|---|---|---|
| Tensile Strength, MPa | ≥1275 | ≥1240 | GH4169 +35 MPa |
| Yield Strength (0.2%), MPa | ≥1035 | ≥1034 | Virtually identical |
| Elongation, % | ≥12 | ≥12 | None |
| Hardness, HRC | 33 – 40 | 33 – 40 | None |
| Density, g/cm³ | 8.24 | 8.19 | ~0.6% difference |
| Melting Range, °C | 1260 – 1340 | 1260 – 1336 | Virtually identical |
| Max Service Temp, °C | 650 – 700 | 650 – 700 | None |
Both alloys are typically supplied in the solution-annealed condition and require post-fabrication age hardening. The standard heat treatment cycle for both is: solution treatment at 950–980°C / 1h / air cool, followed by two-step aging at 720°C / 8h / furnace cool to 620°C, then 620°C / 8h / air cool.
GH4169 vs Inconel 718: Corrosion Resistance Comparison
Because their chemistries are nearly identical, GH4169 and Inconel 718 have equivalent corrosion resistance. Both offer good general corrosion resistance and excellent stress-corrosion cracking resistance in chloride environments. The 17–21% chromium content provides good oxidation resistance up to 900°C, while the 2.8–3.3% molybdenum adds pitting and crevice corrosion resistance.
| Corrosion Type | GH4169 | Inconel 718 |
|---|---|---|
| General Corrosion | ★★★★☆ | ★★★★☆ |
| Pitting / Crevice | ★★★☆☆ | ★★★☆☆ |
| Stress Corrosion Cracking | ★★★★★ | ★★★★★ |
| Oxidation (900°C) | ★★★★☆ | ★★★★☆ |
| H&sub2;S Sour Service | ★★★★☆ | ★★★★☆ |
Note: While 718/GH4169 has lower pitting resistance than alloys like Inconel 625 or Incoloy 825 due to its lower molybdenum content, its 50%+ nickel content ensures immunity to chloride stress corrosion cracking - a critical advantage over stainless steels in oil and gas downhole environments.
GH4169 vs Inconel 718: Real Shot of Spray-Marked Round Bars
GH4169 vs Inconel 718: Heat Treatment Comparison
Both GH4169 and Inconel 718 use the same double-aging heat treatment to achieve maximum strength. The process precipitates the gamma double-prime (γ'') Ni&sub3;Nb phase, which is the primary strengthening mechanism:
| Heat Treatment Step | GH4169 | Inconel 718 |
|---|---|---|
| Solution Treatment | 950–980°C / 1h / AC | 954–982°C / 1h / AC |
| First Aging | 720°C / 8h / FC to 620°C | 718°C / 8h / FC to 621°C |
| Second Aging | 620°C / 8h / AC | 621°C / 8h / AC |
| Total Cycle Time | ~18 hours | ~18 hours |
The heat treatment cycles are functionally identical - only the temperature labels differ slightly due to rounding between Celsius and Fahrenheit conversions (718°C = 1325°F, 621°C = 1150°F). Both produce the same γ'' precipitate structure and achieve the same mechanical properties.
GH4169 vs Inconel 718: Standards and Certification Comparison
While the material itself is nearly identical, the real differences between GH4169 and Inconel 718 lie in the standard system, certification, and supply chain economics:
| Category | GH4169 | Inconel 718 |
|---|---|---|
| Standard System | GB/T 14992 (Chinese) | ASTM / AMS (Western) |
| UNS Designation | N07718 (equivalent) | N07718 |
| W.Nr. (EU) | 2.4668 (equivalent) | 2.4668 |
| Aerospace Standard | HB 5312, GJB 2611 | AMS 5662, 5596, 5663 |
| Material Test Certificate | GB 3.1 / EN 10204 3.1 | EN 10204 3.1 / 3.2 |
| Aerospace Approval | CAAC equivalent | FAA / EASA NADCAP |
| Brand Name | Generic (GH prefix) | Special Metals (branded) |
| Relative Price | 1.0x (more cost-effective) | 1.2–1.5x (premium) |
| Lead Time (China) | 15–30 days | 30–90 days (imported) |
GH4169 vs Inconel 718: Quick Selection Guide
| ✓ Choose GH4169 When | ✗ Choose Inconel 718 When |
|---|---|
| Your project follows Chinese GB/ASME standards | The project requires ASTM/AMS specification |
| Cost optimization is a priority (20–35% savings) | NADCAP / FAA aerospace certification is mandatory |
| Faster delivery needed from domestic Chinese mills | End customer explicitly specifies "Inconel 718" |
| Petrochemical, energy, and industrial turbine parts | Western OEM aerospace / defense programs |
| Oil and gas downhole tools and wellhead components | Requires brand-name traceability to Special Metals |
| Nuclear power plant components (China domestic) | Export to countries requiring Western standards |
GH4169 vs Inconel 718: Weldability Comparison
Both GH4169 and Inconel 718 are considered readily weldable for a precipitation-hardening superalloy. This is one of the key reasons 718 is the most widely used superalloy - unlike many other high-strength superalloys, it resists strain-age cracking during welding and can be joined in both the solution-annealed and aged conditions.
Recommended welding processes include GTAW (TIG), GMAW (MIG), SMAW (stick), and electron beam welding. Matching filler metals are designated as ERNiFeCr-2 (AWS A5.14). Post-weld heat treatment is recommended for full strength recovery, especially for components operating above 540°C. The welding performance of GH4169 and Inconel 718 is functionally identical - the same parameters and procedures apply to both.
GH4169 vs Inconel 718: Application Comparison
Both alloys serve the same application spectrum, with specification choice usually determined by the project's standard requirement:
Where GH4169 / Inconel 718 is the standard choice:
- ✓ Aerospace: Turbine engine discs, blades, shafts, fasteners, and rocket motor components
- ✓ Oil and gas: Downhole tools, wellhead components, valve bodies, and HPHT tool joints
- ✓ Nuclear energy: Reactor components, fuel element spacers, and control rod drive mechanisms
- ✓ Industrial gas turbines: Compressor discs, blade roots, and structural fasteners
- ✓ Medical: Surgical instruments and prosthetic devices requiring high strength and biocompatibility
- ✓ Automotive: High-performance turbocharger wheels and exhaust valves
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Cost Analysis: Why GH4169 Is More Cost-Effective
For buyers sourcing from Chinese manufacturers, GH4169 is typically 20–35% cheaper per kilogram than branded Inconel 718 imported from Western mills. The reasons for this price gap include:
| Cost Factor | GH4169 | Inconel 718 |
|---|---|---|
| Material Price (relative) | 1.0x | 1.2–1.5x |
| Brand Premium | None | 10–20% (Special Metals) |
| Import Tariff / Customs | None (domestic) | Applicable |
| Lead Time | 15–30 days | 30–90 days |
| Material Performance | Equivalent | Equivalent |
⚠ Key Insight: If your project requires Western certification (AMS, NADCAP, AS9100), GNEE Alloy can also supply Inconel 718 to ASTM/AMS standards with full traceability. For non-aerospace industrial applications where GB standard is acceptable, GH4169 offers identical performance at significantly lower cost with faster delivery.
About GNEE Alloy
As an ISO & CE certified Nickel Based Alloy manufacturer with 20 years of experience, GNEE Alloy supplies both GH4169 (GB standard) and Inconel 718 (ASTM/AMS standard) at factory-direct prices. We produce plate, bar, tube, forging, and fastener forms per GB/T 14992, ASTM B637/B670, and AMS 5662. All products come with EN 10204 3.1 MTC, ultrasonic testing, and third-party inspection (SGS, BV, TÜV) supported. For non-aerospace industrial applications, GH4169 delivers identical performance to Inconel 718 at 20–35% lower cost with faster delivery.
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FAQ
Q: Is GH4169 the same as Inconel 718?
A: Yes, for all practical purposes. GH4169 is the Chinese designation (GB/T 14992) and Inconel 718 is the Western brand name (UNS N07718). They have nearly identical chemical compositions, mechanical properties, and corrosion resistance. The main differences are in standard system, certification, and pricing.
Q: What does "GH" mean in GH4169?
A: "GH" stands for "高温合金" (gāowēn héjīn), which translates to "high-temperature alloy" in Chinese. The number 4169 is the alloy designation within the GH series, where the first digit indicates the alloying system (4 = nickel-iron-chromium base).
Q: What is the difference between Incoloy and Inconel?
A: The difference between incoloy and inconel is nickel content: Incoloy grades (like 800, 825) have 30–46% nickel with significant iron, optimized for corrosion resistance at moderate temperatures. Inconel grades (like 600, 625, 718) have ≥50% nickel for superior high-temperature strength. GH4169 falls in the Inconel category at 50–55% nickel.
Q: Can GH4169 replace Inconel 718 in my application?
A: In most industrial applications, yes. The material properties are functionally identical. However, if your project requires AMS spec compliance, NADCAP approval, or the end customer specifically mandates "Inconel 718," you should specify the ASTM-grade version. We can supply both from our mill.
Q: What is the heat treatment for GH4169?
A: The standard double-aging treatment is: solution anneal at 960°C / 1h / AC, then age at 720°C / 8h / furnace cool to 620°C (50°C/h), then 620°C / 8h / AC. This produces the γ'' Ni&sub3;Nb precipitates that give GH4169 its high strength.
Q: Is Inconel a nickel alloy?
A: Yes. Is Inconel a nickel alloy - Inconel 718 and GH4169 both contain 50–55% nickel, making them true nickel-based superalloys. The high nickel content is what provides the excellent SCC resistance and high-temperature stability.
