During the procurement process, Inconel 718 and 316 stainless steel are frequently compared because both are widely used in corrosive and high-performance environments. However, these two materials have distinctly different design purposes and cost structures.
Inconel 718 is a nickel-based superalloy optimized for high strength and high-temperature environments. 316 stainless steel is an austenitic stainless steel optimized for corrosion resistance and cost-effectiveness.
Choosing the wrong material can lead to: over-specification and unnecessary costs, insufficient performance in terms of temperature or load, reduced service life, and increased maintenance costs.
Is Inconel 718 a superalloy?
Inconel 718 (UNS N07718) is a high-strength nickel-chromium superalloy known for its excellent high-temperature resistance (up to 700°C/1300°F), corrosion and oxidation resistance, and superior fatigue and creep strength, making it ideal for applications in aerospace (jet engines, rockets), oil and gas, and power generation. It is age-hardenable, easily machinable, and possesses excellent weldability.
What does 316 mean in stainless steel?
316 stainless steel is an austenitic steel, second only to 304 in popularity, distinguished by adding 2-3% molybdenum, which significantly boosts its resistance to chlorides (like saltwater) and harsh chemicals, making it "marine grade" for coastal, chemical, medical, and food processing applications needing superior corrosion resistance.
Inconel 718 vs. Stainless Steel 316: Differences
Inconel 718 vs. Stainless Steel 316: Alloy Overview & Standards
| Material | UNS No. | Common Standards | Primary Design Purpose |
|---|---|---|---|
| Inconel 718 | N07718 | ASTM B637, AMS 5662 / 5663 | High strength & fatigue resistance |
| Stainless Steel 316 | S31600 | ASTM A240 / A276 | Corrosion resistance & formability |
Inconel 718 vs. Stainless Steel 316: Chemical Composition
| Element | Inconel 718 | Stainless Steel 316 |
|---|---|---|
| Nickel (Ni) | 50–55 | 10–14 |
| Chromium (Cr) | 17–21 | 16–18 |
| Molybdenum (Mo) | 2.8–3.3 | 2.0–3.0 |
| Iron (Fe) | Balance (≤18) | Balance |
| Niobium (Nb) | 4.75–5.50 | - |
| Carbon (C) | ≤0.08 | ≤0.08 |
Inconel 718 vs. Stainless Steel 316: Mechanical Properties
| Property | Inconel 718 (Aged) | Stainless Steel 316 |
|---|---|---|
| Yield Strength (0.2%) | ≥1,000 MPa | ~205 MPa |
| Tensile Strength | 1,250–1,450 MPa | ~515 MPa |
| Elongation | 12–20% | ~40% |
| Hardness | 36–45 HRC | ~150–190 HB |
Inconel 718 vs. Stainless Steel 316:Temperature Performance Comparison
| Performance Factor | Inconel 718 | Stainless Steel 316 |
|---|---|---|
| Continuous service temperature | Up to ~650°C | Up to ~425°C |
| Short-term exposure | ~700°C | ~870°C (no load) |
| Creep resistance | Excellent | Poor |
| Strength retention at high temp | Excellent | Rapid loss |
Inconel 718 vs. Stainless Steel 316: Corrosion Resistance
Due to its nickel-based composition, Inconel 718 offers significantly better corrosion resistance than stainless steel 316, while stainless steel 316 is a better choice for general industrial, marine, and food-grade applications where cost is a major consideration. Inconel performs exceptionally well in extreme oxidizing, high-stress, and reducing corrosive environments, maintaining its strength even where 316 stainless steel fails, but it is also more expensive.
Inconel 718 suppliers
At GNEE, Inconel 718 is available in various forms to meet diverse industrial needs:
Plates and Sheets (cold rolled and hot rolled)
Bars and Rods (round, square, hexagonal)
Tubes (seamless and welded)
Wires and Strips (for springs, fasteners, electrical applications)
Forgings and Custom Parts (according to drawings or specifications)
Specifications: UNS NO7718, WNR 2.4668, AFNOR NC19FeNb, JIS NCF 718, GOST ХН75МБТЮ, EURONORM NiCr22Mo9Nb, OR ЭИ602, BS NA 21.
Temperature Range: -423°F to 1300°F.
Testing and Documentation: Mill Test Certificates, EN 10204 3.1, Chemical Reports, Mechanical Reports, Destructive Testing Reports, Non-Destructive Testing Reports, PMI Test Reports, Visual Inspection Reports, Third-Party Inspection Reports, NABL Certified Laboratory Reports.
Packaging: Wooden crates, bubble wrap, steel strapping, or packaged according to customer requirements.
