Haynes 718 alloy,UNS N07718, 1

### **Haynes® 718 Alloy (UNS N07718) - Nickel-Chromium Precipitation-Hardenable Superalloy** #### **Overview** **Haynes® 718 Alloy** (commonly known as **Inconel® 718**) is a precipitation-hardenable nickel-chromium alloy containing significant amounts of iron, niobium, and molybdenum along with smaller additions of aluminum and titanium. This superalloy exhibits an exceptional combination of high strength, excellent creep resistance, and good corrosion resistance up to 1300°F (704°C). The alloy's primary strengthening mechanism comes from the precipitation of gamma prime (γ') and gamma double prime (γ'') phases, with the latter (Ni₃Nb) providing the predominant strengthening effect. --- #### **Chemical Composition (Weight %)** | Element | Content (%) | Function | |---------|-------------|-----------| | **Nickel (Ni)** | **50.0-55.0** | **Base element providing matrix stability** | | **Chromium (Cr)** | **17.0-21.0** | **Oxidation and corrosion resistance** | | **Iron (Fe)** | **Balance** | **Cost-effective matrix element** | | **Niobium (Nb)** | **4.75-5.50** | **Primary strengthening via γ'' (Ni₃Nb) formation** | | **Molybdenum (Mo)** | **2.80-3.30** | **Solid solution strengthening and pitting resistance** | | **Titanium (Ti)** | **0.65-1.15** | **Forms γ' (Ni₃(Al,Ti)) strengthening phase** | | **Aluminum (Al)** | **0.20-0.80** | **Forms γ' (Ni₃(Al,Ti)) strengthening phase** | | **Cobalt (Co)** | **≤ 1.00** | **Controlled impurity** | | **Carbon (C)** | **≤ 0.08** | **Controlled for carbide formation** | | **Manganese (Mn)** | **≤ 0.35** | **Deoxidizer** | | **Silicon (Si)** | **≤ 0.35** | **Controlled impurity** | | **Phosphorus (P)** | **≤ 0.015** | **Controlled impurity** | | **Sulfur (S)** | **≤ 0.015** | **Controlled impurity** | | **Boron (B)** | **≤ 0.006** | **Grain boundary strengthening** | --- #### **Physical Properties** | Property | Value / Description | |----------|---------------------| | **Density** | **8.19 g/cm³ (0.296 lb/in³)** | | **Melting Range** | **1260-1336°C (2300-2440°F)** | | **Electrical Resistivity** | **1.25 μΩ·m** | | **Thermal Conductivity** | **11.4 W/m·K (at 100°C)** | | **Coefficient of Thermal Expansion** | **13.0 μm/m·°C (20-100°C)** | | **Specific Heat Capacity** | **435 J/kg·K** | | **Magnetic Permeability** | **< 1.01 (slightly magnetic)** | --- #### **Mechanical Properties (Solution Annealed & Aged)** | Temperature | Tensile Strength | Yield Strength (0.2%) | Elongation | |-------------|------------------|---------------------|------------| | **Room Temperature** | **1380 MPa (200 ksi)** | **1170 MPa (170 ksi)** | **20%** | | **650°C (1200°F)** | **1140 MPa (165 ksi)** | **965 MPa (140 ksi)** | **18%** | | **760°C (1400°F)** | **930 MPa (135 ksi)** | **760 MPa (110 ksi)** | **22%** | --- #### **Heat Treatment Response** | Treatment | Temperature | Time | Cooling | Purpose | |-----------|-------------|------|---------|---------| | **Solution Annealing** | **954-1010°C (1750-1850°F)** | **1 hour** | **Rapid Air or Faster** | **Dissolve precipitates** | | **Aging Treatment** | **718°C (1325°F)** | **8 hours** | **Furnace Cool to 621°C** | **γ'' precipitation** | | **Second Aging** | **621°C (1150°F)** | **8 hours** | **Air Cool** | **Additional strengthening** | --- #### **Key Characteristics & Applications** **Key Characteristics:** - **Exceptional High-Temperature Strength**: Maintains properties up to 704°C (1300°F) - **Excellent Creep Resistance**: Superior long-term stability under load - **Good Fatigue Resistance**: Excellent performance under cyclic loading - **Outstanding Weldability**: Can be welded in both annealed and aged conditions - **Resistance to Post-Weld Cracking**: Minimal susceptibility to strain-age cracking - **Good Corrosion Resistance**: Performs well in various corrosive environments **Typical Applications:** - **Aerospace Industry**: Gas turbine engine components, discs, blades, and shafts - **Power Generation**: Gas turbine components, fasteners, and structural parts - **Oil & Gas Industry**: Downhole tools, wellhead components, and valves - **Nuclear Industry**: Reactor core components and structural applications - **Rocket Motors**: Liquid-fueled rocket engine components - **Chemical Processing**: High-temperature reaction vessels and heat exchangers - **Automotive**: Turbocharger components and high-performance engine parts --- #### **International Standards & Specifications** | Standard | Designation | Description | |----------|-------------|-------------| | **UNS** | **N07718** | **Unified Numbering System** | | **AMS** | **5596** | **Sheet, Strip, and Plate** | | **AMS** | **5597** | **Welding Wire** | | **AMS** | **5662** | **Bar, Forgings, and Rings** | | **AMS** | **5664** | **Solution Heat Treated Bar and Forgings** | | **AMS** | **5832** | **Welding Wire** | | **AMS** | **5589** | **Seamless Tube** | | **AMS** | **5590** | **Welded Tube** | | **NACE** | **MR-01-75** | **Sulfide Stress Cracking Resistant Metallic Materials** | | **ASTM** | **B626** | **Welded Tube** | --- #### **Manufacturing & Processing** **Available Forms:** - **Bar and Rod**: 3 mm to 500 mm diameter - **Plate and Sheet**: 0.5 mm to 150 mm thickness - **Pipe and Tube**: 6 mm to 600 mm diameter - **Wire and Strip**: Various sizes for specialized applications - **Forgings and Rings**: Custom components for critical applications **Processing Guidelines:** - **Hot Working**: 1020-1120°C (1870-2050°F) - **Cold Working**: Good capability with intermediate annealing - **Solution Treatment**: 954-1010°C (1750-1850°F) with rapid cooling - **Welding**: Excellent weldability using GTAW, GMAW, SMAW processes - **Machining**: More challenging than steel but manageable with proper techniques --- #### **Corrosion & Environmental Resistance** | Environment | Performance | Temperature Limit | |-------------|-------------|-------------------| | **Oxidation Resistance** | **Excellent** | **Up to 980°C (1800°F)** | | **Sulfide Stress Cracking** | **Excellent** | **NACE MR-01-75 compliant** | | **Chloride Stress Corrosion** | **Good** | **Moderate temperatures** | | **Aqueous Corrosion** | **Very Good** | **Various environments** | --- #### **Quality Control & Testing** - **Chemical Analysis**: Per ASTM E1473 - **Mechanical Testing**: Per ASTM E8/E8M and E21 - **Creep and Stress Rupture**: Per ASTM E139 and E292 - **Non-Destructive Testing**: UT, RT, PT, ET as required - **Microstructural Examination**: Per ASTM E112 and E407 - **Hardness Testing**: Per ASTM E10 and E18 --- #### **Comparison with Competitive Alloys** | Property | Alloy 718 | Waspaloy | Alloy 625 | A-286 | |----------|-----------|----------|-----------|-------| | **Max Service Temperature** | **704°C** | **815°C** | **980°C** | **650°C** | | **Strength Level** | **Very High** | **High** | **Medium** | **Medium** | | **Fabricability** | **Excellent** | **Good** | **Excellent** | **Good** | | **Cost Effectiveness** | **High** | **Medium** | **High** | **High** | --- #### **Summary** **Haynes® 718 Alloy (UNS N07718)** represents one of the most versatile and widely used precipitation-hardenable nickel-based superalloys, offering an outstanding combination of high strength, excellent fabricability, and good corrosion resistance. Its comprehensive standardization across multiple AMS specifications (5596, 5597, 5662, 5664, 5832, 5589, 5590) and compliance with NACE MR-01-75 ensures consistent quality and reliable performance in critical applications. The alloy's unique ability to be readily welded without post-weld heat treatment cracking, combined with its robust mechanical properties up to 704°C, has established it as the material of choice for demanding applications in aerospace, power generation, and oil & gas industries. Supported by decades of service experience and continuous process improvements, Alloy 718 continues to be the benchmark for high-strength, high-temperature applications where reliability and performance are paramount.

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 3245 gallon liquid totes Special package is available on request.