GH4169 (Inconel 718) Buying Guide: Heat Treatment and Machining Understanding
GH4169 (Inconel 718) Buying Guide: Heat Treatment and Machining Understanding
GH4169 (equivalent to Inconel 718) is a precipitation-hardening nickel-based superalloy known for its high strength, excellent corrosion resistance, and stability at temperatures up to 650°C (1200°F). It is commonly used in aerospace turbine components, nuclear reactors, and oilfield applications.
What is the standard heat treatment process for Inconel 718?
Inconel 718 alloy is typically treated with two heat treatment processes: • Solution annealing at 1700-1850°F, followed by rapid cooling (usually with water) and precipitation hardening at 1325°F for 8 hours, furnace cooling to 1150°F, holding at 1150°F for 18 hours, and finally air cooling.
1. GH4169 (Inconel 718) Equivalent Grades
Chinese Standard GB/T 15007-2017: GB GH4169 (GH169) / ISC H41690
American Standard ASTM B 637-2018: Inconel 718 / UNS N07718 / SAE XEV-1
American Standard SAE AMS 5596 M-2017: AMS 5596
German Standard EN 10269-2013: DIN NiCr19NbMo / DIN NiCr19Fe19Nb5Mo3 / W-Nr. 2.4668
French Standard: NF ATG C1 / NF NC19FeNb
GH4169 (Inconel 718)
2. Chemical composition of GH4169 (Inconel 718)
| Element | Weight % | |
|---|---|---|
|
|
Nickel (Ni) | 50 – 55 |
| Chromium (Cr) | 17 – 21 | |
| Iron (Fe) | Balance (Rest) | |
| Molybdenum (Mo) | 2.8 – 3.3 | |
| Niobium (Nb) | 4.75 – 5.5 | |
| Titanium (Ti) | 0.65 – 1.15 | |
| Aluminum (Al) | 0.2 – 0.8 | |
| Cobalt (Co) | ≤ 1 | |
| Manganese (Mn) | ≤ 0.35 | |
| Silicon (Si) | ≤ 0.35 | |
| Carbon (C) | ≤ 0.08 | |
| Phosphorus (P) | ≤ 0.015 | |
| Sulfur (S) | ≤ 0.015 | |
| Boron (B) | ≤ 0.006 | |
| Copper (Cu) | ≤ 0.3 |
3. GH4169 - UNS N07718 High Temperature Alloy Mechanical Properties
| Element | Yield Strength (0.2%Offset) | Melting Point | Density | Tensile Strength | Elongation |
| GH4169/718 | MPa – 1034 | 1336 °C (2437 °F) | 8.19 g/cm3 | MPa – 1241 | Min 10 % |
4. GH4169 Main Technical Data Sheet
| Property Category | Standard Benchmark | Our Premium Quality Advantage |
| Yield Strength | ≥ 1030 MPa | Optimized via precise Double-Aging cycles. |
| Machinability | Low (Difficult) | We supply in Solution Treated state for easier cutting. |
| Welding | Excellent | Slow aging response prevents spontaneous cracking. |
| Purity Process | EAF + ESR | VIM + VAR (Double Melting) for zero inclusions. |
| Certification | GB/T 14992 | Fully compliant with AMS 5662 / ASTM B637. |
Click here to download the GH4169 alloy PDF file now
5. GH4169 Heat Treatment Principle
Heat treatment is crucial for the formation of γ'(Ni3Nb) and γ' precipitates, which impart high strength to the material. (City University of Hong Kong)
Solution Annealing: Heating to 930°C-1065°C (1700°F-1950°F), followed by rapid cooling (water/oil quenching or rapid air cooling). This process dissolves unwanted phases and prepares the material for aging treatment.
Aging/Precipitation Hardening (Two-Step Standard Process):
1. Heating to 720°C (1325°F) and holding for 8 hours.
2. Furnace cooling at a rate of 55°C/hour to 620°C (1150°F), holding for 8 hours, followed by air cooling.
Stress Relief: Performed after severe machining or welding to prevent cracking, typically at 600°C-850°C, depending on the desired final state.
6. GH4169 Application Scope
As a reliable supplier, Gnee Alloy offers certified GH4169 products:
✅️Aerospace: Turbine discs, engine shafts, and High-Tension Fasteners.
✅️Oil & Gas: Downhole tools and wellhead components requiring NACE MR0175 compliance.
✅️Nuclear: High-strength structural members and springs in reactor cores.
✅️Automotive: High-performance turbocharger components and exhaust valves.
Why should we source from our Tier 1 supplier, Gnee Alloy?
✅️VIM + VAR Melting: Mandatory double-vacuum melting ensures zero "freckles" (macro-segregation) and maximizes fatigue life.
✅️100% Traceability: Every order includes an EN 10204 3.1 Mill Test Certificate (MTC) documenting grain size and tensile results.
✅️Wholesale Inventory: Massive stock of forged bars, precision sheets, and seamless tubes for Fast Global Shipping.
✅️Direct Factory Price: Eliminate middleman markups and secure the best rates for bulk procurement.
Contact us now to get the latest export price for GH4169 in 2026
FAQ
Q1: Is GH4169 exactly the same as Inconel 718?
A: Yes. GH4169 is the technical designation within the Chinese GB/T system for the metallurgical system known globally as Inconel 718 (UNS N07718). They are globally interchangeable.
Q2: How do I reduce the risk of "Hot Cracking" during welding?
A: GH4169 is the most weld-friendly superalloy because of its slow aging response. To ensure zero defects, always ensure the surface is ultra-clean (no sulfur-based oils) and use matching ERNiCr-3 or specialized 718 filler wire.
Q3: Can I get GH4169 bars in large diameters for shafts?
A: Absolutely. We maintain a Wholesale Inventory of forged bars up to 450mm diameter, all 100% Ultrasonic Tested (UT Class A) to ensure internal integrity.
Q4: Do you offer bulk discounts for aerospace maintenance programs?
A: Yes. We support long-term MRO contracts with attractive volume-based pricing and dedicated inventory reserves.
