Inconel 718 (UNS N07718) – Supplier of Round Bars, Seamless Tubes & Plates | Shanghai Hangbo Alloy Group
Date: 2026年7月10日 Categories: News Views: 430
Section 1: Grade & Introduction
Inconel 718 (UNS N07718 / W.Nr. 2.4668) is a high-strength, precipitation-hardenable nickel-chromium superalloy. It is designed to exhibit exceptionally high yield, tensile, and creep-rupture properties at temperatures up to 704°C (1300°F). The addition of niobium, molybdenum, aluminum, and titanium allows for a unique strengthening mechanism that also provides excellent weldability and resistance to post-weld cracking.
Section 2: Chemical Composition
The chemical composition of Inconel 718 is strictly controlled to ensure its superior performance. Below is the precise weight percentage (wt.%) based on ASTM B670 standards.
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 50.0 - 55.0 |
| Chromium (Cr) | 17.0 - 21.0 |
| Iron (Fe) | 11.1 - 22.5 (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 |
| Phosphorus (P) | ≤ 0.015 |
| Sulfur (S) | ≤ 0.015 |
| Boron (B) | ≤ 0.006 |
| Copper (Cu) | ≤ 0.30 |
Section 3: Mechanical & Physical Properties
Inconel 718 offers a combination of excellent physical properties and high mechanical strength, particularly after precipitation hardening.
Physical Properties
- Density: 8.19 g/cm³
- Melting Range: 1260 - 1336°C (2300 - 2437°F)
- Specific Heat: 435 J/kg·°C
Mechanical Properties (Min. values at Room Temp according to ASTM B637/B670)
| Condition | Tensile Strength (MPa) | Yield Strength (0.2% Offset) (MPa) | Elongation (%) |
|---|---|---|---|
| Precipitation Hardened | 1241 | 1034 | 12 |
Section 4: Material Characteristics
- High Strength: Maintains exceptional tensile and creep-rupture strength at cryogenic temperatures up to 704°C.
- Excellent Weldability: Sluggish aging response allows for welding without the high risk of strain-age cracking.
- Corrosion Resistance: Excellent resistance to oxidation and other corrosive media across its entire operating temperature range.
- Fabricability: Good hot and cold working properties compared to other age-hardenable superalloys.
Section 5: Others
Manufacturing & Processing
Manufacturing involves hot working between 927°C and 1121°C, followed by solution annealing and a two-stage aging process to achieve peak properties. Cold working is also feasible for precision shapes.
Testing
Quality assurance includes Ultrasonic Testing (UT) for internal integrity, Positive Material Identification (PMI), and tensile testing per ASTM E8.
Applications
Widely used in aerospace (jet engine components), oil and gas (high-strength valves and fasteners), and nuclear reactor components.
Global Cases
Supplied to major aerospace contractors for turbine discs and oilfield service providers for downhole tools in HPHT (High Pressure High Temperature) environments.
FAQ
- What is the difference between Inconel 718 and 625? 718 is precipitation hardenable for higher strength, while 625 is solid-solution strengthened for better corrosion resistance.
- Can Inconel 718 be welded? Yes, it is one of the most weldable age-hardenable superalloys.
- What is the maximum operating temperature? Typically up to 704°C (1300°F) for strength-critical applications.
- What standards apply to 718 plates? Primarily ASTM B670 and ASME SB-670.
- Does it require heat treatment after welding? Yes, full aging is recommended to restore mechanical properties.
