718 Nickel Superalloy, UNS N07718; AMS 5662, 5663, 5664. MIL-N-24469, RDT M2-18T, ASTM B 637,E FORU

**Product Overview: 718 Nickel Superalloy (UNS N07718)** **Alloy 718** (UNS N07718) is a premier precipitation-hardenable nickel-chromium superalloy containing significant amounts of iron, niobium, and molybdenum. It is one of the most widely used superalloys due to its exceptional combination of high strength, excellent corrosion resistance, and superior weldability. The alloy demonstrates outstanding mechanical properties from cryogenic temperatures up to 705°C (1300°F) and is particularly noted for its resistance to post-weld strain-age cracking. --- ### **Key Characteristics & Advantages** - **Excellent High-Temperature Strength**: Maintains mechanical properties up to 705°C (1300°F) - **Superior Corrosion Resistance**: Excellent resistance to oxidation and corrosion - **Outstanding Weldability**: Can be welded in the aged condition without post-weld heat treatment cracking - **Good Fabricability**: Excellent machinability and formability - **High Strength-to-Weight Ratio**: Ideal for aerospace applications - **Resistance to Creep and Stress Rupture**: Performs well under prolonged stress at elevated temperatures --- ### **Chemical Composition (Typical Weight %)** | Element | Content Range (%) | Function Description | |------------------|-------------------|-----------------------| | **Nickel (Ni)** | 50.0-55.0 | Base element providing austenitic matrix | | **Chromium (Cr)**| 17.0-21.0 | Primary element for oxidation and corrosion resistance | | **Iron (Fe)** | Balance | Major alloying element providing solid solution strengthening | | **Niobium (Nb)** | 4.75-5.50 | Forms γ'' strengthening phase with nickel | | **Molybdenum (Mo)**| 2.80-3.30 | Solid solution strengthener | | **Titanium (Ti)**| 0.65-1.15 | Contributes to γ' precipitation hardening | | **Aluminum (Al)**| 0.20-0.80 | Forms γ' precipitation hardening phase | | **Cobalt (Co)** | ≤1.00 | Controlled impurity | | **Carbon (C)** | ≤0.08 | Controlled for carbide formation | | **Boron (B)** | ≤0.006 | Enhances grain boundary strength | --- ### **Physical Properties** | Property | Typical Value | Test Conditions | |---------------------------------|------------------------|--------------------------| | **Density** | 8.19 g/cm³ | At room temperature | | **Melting Range** | 1260-1336°C | Solidus-Liquidus | | **Thermal Expansion Coefficient**| 13.0 × 10⁻⁶/°C | 20-100°C range | | **Thermal Conductivity** | 11.4 W/m·K | At 100°C | | **Specific Heat Capacity** | 435 J/kg·K | At 100°C | | **Electrical Resistivity** | 1.25 μΩ·m | At 20°C | | **Young's Modulus** | 200 GPa | At room temperature | --- ### **Mechanical Properties** #### **Solution Treated and Aged Condition** | Property | Temperature | Typical Value | |------------------------|-------------|----------------------| | **Tensile Strength** | 20°C | 1310 MPa min | | **Tensile Strength** | 650°C | 1000 MPa min | | **Yield Strength (0.2%)** | 20°C | 1035 MPa min | | **Yield Strength (0.2%)** | 650°C | 860 MPa min | | **Elongation** | 20°C | 12% min | | **Elongation** | 650°C | 12% min | | **Reduction of Area** | 20°C | 15% min | | **Creep Rupture Strength** | 650°C | 480 MPa (100h) | --- ### **Heat Treatment** Standard heat treatment sequence includes: - **Solution Treatment**: 950-980°C for 1 hour, air cool or faster - **Aging Treatment**: 720°C for 8 hours, furnace cool to 620°C at 55°C/hour - **Hold at 620°C**: 8 hours total aging time, air cool --- ### **International Standards & Specifications** Alloy 718 complies with the following international standards: - **AMS 5662**: Bars, Forgings, and Rings - **AMS 5663**: Fastener Stock - **AMS 5664**: Investment Castings - **MIL-N-24469**: Military Specification - **RDT M2-18T**: Nuclear Application Specification - **ASTM B637**: Precipitation Hardening Nickel Alloy Bars, Forgings, and Forging Stock --- ### **Applications** 1. **Aerospace Industry**: - Gas turbine engine components - Turbine blades and disks - Compressor parts - Rocket engine components - Aircraft structural components 2. **Oil and Gas Industry**: - Downhole tools and equipment - Wellhead components - Valves and pumps - Subsea equipment 3. **Nuclear Applications**: - Reactor core components - Heat exchangers - Control rod mechanisms - Nuclear waste containers 4. **Power Generation**: - Gas turbine components - Steam turbine parts - High-temperature fasteners - Pressure vessels --- ### **Manufacturing Considerations** - **Forging**: Hot workable in temperature range 950-1120°C - **Machining**: Good machinability in annealed condition - **Welding**: Excellent weldability using matching filler metals - **Heat Treatment**: Requires precise control of time-temperature parameters - **Quality Control**: Stringent NDT requirements --- ### **Available Forms** - **Bar and Rod**: Various diameters and lengths - **Forgings**: Custom shapes and sizes - **Sheet and Plate**: Multiple thicknesses - **Fasteners**: Bolts, nuts, and special fasteners - **Wire**: For welding and special applications - **Investment Castings**: Complex components --- **Disclaimer**: *The information provided is for technical reference purposes only. Alloy 718 is a specialized superalloy requiring proper processing and heat treatment to achieve specified properties. Actual performance may vary depending on manufacturing processes, heat treatment parameters, and specific application conditions. Users should consult with qualified materials engineers and adhere to OEM specifications for critical applications. All manufacturing and processing should follow approved procedures and quality standards.*

Packing of 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 3124 gallon liquid totes Special package is available on request.