Alloy 718,Inconel 718,UNS N07718,EFORU

--- ### **Technical Datasheet: Alloy 718 (Inconel 718, UNS N07718)** 

 **Introduction** 

Alloy 718, commonly known by its trade name Inconel 718, is a precipitation-hardenable nickel-chromium superalloy. It is renowned for its exceptional combination of high strength, excellent corrosion resistance, and outstanding weldability. Its key characteristic is the addition of significant amounts of niobium and molybdenum, which enable it to be strengthened by aging heat treatments without a subsequent quenching step, making it resistant to strain-age cracking. This makes it the material of choice for high-stress applications in aerospace, oil & gas, and power generation industries, particularly at temperatures from cryogenic levels up to about 700°C (1300°F). 

--- ### **Technical Datasheet: Alloy 718 (Inconel 718, UNS N07718)** 

 **Introduction** 

Alloy 718, commonly known by its trade name Inconel 718, is a precipitation-hardenable nickel-chromium superalloy. It is renowned for its exceptional combination of high strength, excellent corrosion resistance, and outstanding weldability. Its key characteristic is the addition of significant amounts of niobium and molybdenum, which enable it to be strengthened by aging heat treatments without a subsequent quenching step, making it resistant to strain-age cracking. This makes it the material of choice for high-stress applications in aerospace, oil & gas, and power generation industries, particularly at temperatures from cryogenic levels up to about 700°C (1300°F). 

 **Key Features** *   

**High Strength-to-Weight Ratio:** Maintains high yield and tensile strength over a wide temperature range. *   

**Excellent Corrosion Resistance:** Resists oxidation, corrosion, and pitting in severe environments. *   

**Superior Creep and Rupture Strength:** Performs reliably under constant stress at elevated temperatures. *   

**Outstanding Weldability:** Can be welded in the annealed condition and directly aged, with minimal risk of post-weld cracking. *   

**Good Fabricability:** Can be forged, machined, and formed using standard techniques for high-temperature alloys. 

1. Chemical Composition (Weight %)** 

 The typical composition of Alloy 718 is specified in various international standards. The following is a representative range: 

 | Element | Minimum (%) | Maximum (%) | 

| :--- | :--- | :--- | 

| **Nickel (Ni)** | 50.0 | 55.0 | 

| **Chromium (Cr)** | 17.0 | 21.0 | 

| **Iron (Fe)** | Balance | - | 

| **Niobium (Nb) + Tantalum (Ta)** | 4.75 | 5.50 | 

| **Molybdenum (Mo)** | 2.80 | 3.30 | 

| **Titanium (Ti)** | 0.65 | 1.15 | 

| **Aluminum (Al)** | 0.20 | 0.80 | 

| **Cobalt (Co)** | - | 1.00 | 

| **Carbon (C)** | - | 0.08 | 

| **Manganese (Mn)** | - | 0.35 | 

| **Silicon (Si)** | - | 0.35 | 

| **Copper (Cu)** | - | 0.30 | 

| **Phosphorus (P)** | - | 0.015 | 

| **Sulfur (S)** | - | 0.015 | 

| **Boron (B)** | - | 0.006 | 

 *The primary strengthening phases are gamma prime [Ni₃(Al,Ti)] and, more significantly, gamma double prime [Ni₃Nb].* 

2. Physical Properties** 

 | Property | Value | 

| :--- | :--- | 

| **Density** | 8.19 g/cm³ (0.296 lb/in³) | 

| **Melting Range** | 1260 - 1336 °C (2300 - 2440 °F) | 

| **Specific Heat (20°C)** | 435 J/kg·K | 

| **Thermal Conductivity (20°C)** | 11.4 W/m·K | 

| **Mean Coefficient of Thermal Expansion (20-100°C)** | 13.0 µm/m·°C | 

| **Electrical Resistivity** | 1.25 x 10⁻⁶ Ω·m | 

| **Modulus of Elasticity (Young's Modulus)** | 204 GPa (29.5 x 10⁶ psi) | 

 --- #### **3. Mechanical Properties 

(Typical for Solution Treated and Aged Condition)** 

 Properties can vary with product form and specific heat treatment. The following are typical minimums for bar and plate products. **Room Temperature:** *   

**Tensile Strength:** ≥ 1275 MPa (185 ksi) *   

**Yield Strength (0.2% Offset):** ≥ 1035 MPa (150 ksi) *   

**Elongation:** ≥ 12% *   

**Reduction of Area:** ≥ 15% **At 650°C (1200°F):** *   

**Tensile Strength:** ~ 1000 MPa (145 ksi) *   

**Yield Strength (0.2% Offset):** ~ 825 MPa (120 ksi) *   

**Elongation:** ~ 15%

 --- #### **4. International Standards** 

 Alloy 718 is covered by a wide range of international specifications, depending on the product form. 

 | Product Form | Standard Examples | 

| :--- | :--- | 

| **Bar, Wire, Forgings** | AMS 5662, AMS 5663, ASTM B637, DIN 2.4668, UNS N07718 | 

| **Plate, Sheet, Strip** | AMS 5596, AMS 5597, ASTM B670 | 

| **Tubing** | AMS 5589, ASTM B516, ASTM B517 | 

| **Billet & Reforging Stock** | AMS 5664 | 

| **European Standard** | **EN:** NiCr19Fe19Nb5Mo3 | 

| **ISO Standard** | **ISO 9723/9724/9725** (for various forms) | 

-- #### **5. Product Applications** 

 Alloy 718 is a critical material in the most demanding engineering fields: *   

**Aerospace & Jet Engines:**    *   

Turbine blades, discs, and shafts    *  

 Compressor casings and rings    *   

Afterburner components    *   

Rocket motor cases and thrust chambers *   

**Oil & Gas Industry:**    *   

Downhole wellhead components (hangers, packers)    *   

Subsea Christmas trees and valves    *   

High-strength fasteners for sour service (H₂S environments) *   

**Power Generation:**    *   

Gas turbine blades, discs, and bolts    *   

Nuclear reactor core components *   

**Other Industrial Applications:**    *   

High-temperature fasteners and bolts    *   

Tooling for isothermal forging    *   

Chemical processing equipment --- 

 **Conclusion** 

Alloy 718 (Inconel 718, UNS N07718) remains one of the most versatile and widely used nickel-based superalloys. Its unique balance of manufacturability, high strength, and corrosion resistance ensures its continued dominance in critical high-performance applications across the globe.

Packing of Alloy 718 (Inconel 718, UNS N07718) 

 Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1636 gallon liquid totes Special package is available on request.