Inconel 718 has a lower thermal conductivity than 304 stainless steel. At room temperature, the thermal conductivity of Inconel 718 is approximately 11.4 W/m-K, while that of 304 stainless steel is approximately 16.2 W/m-K. The thermal conductivity of Inconel 718 is also highly dependent on its metallurgical state and thermal history, while the thermal conductivity of 304 stainless steel is more stable. This difference means that 304 stainless steel has a higher thermal conductivity than Inconel 718.
What is the thermal conductivity of 304 stainless steel?
304 stainless steel has a melting point of 1430 degrees Celsius, a density of 8.00 g/cm³, a coefficient of thermal expansion of 17.2 × 10⁻⁶/K, an elastic modulus of 193 GPa, and a thermal conductivity of 16.2 W/m·K.
Inconel 718 Chemical Compositions
| Grade | Standard | C | Si | Mn | P | S | Cr | Ni | Ti |
| Inconel 718 | ASTM B 670, ASTM B 906, SAE AMS 5596 | ≤0.08 | ≤0.35 | ≤0.35 | ≤0.015 | ≤0.015 | 17.00-21.00 | 50.0-55.0 | 0.65-1.15 |
Inconel 718 Mechanical Properties
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 8.28 g/cm3 | 1390 °C (2540 °F) | MPa – 910 | MPa – 550 | 25 % |
304 stainless steel Chemical Compositionsa)
| Element | % Present |
|---|---|
| Carbon (C) | 0.07 |
| Chromium (Cr) | 17.50 - 19.50 |
| Manganese (Mn) | 2.00 |
| Silicon (Si) | 1.00 |
| Phosphorous (P) | 0.045 |
| Sulphur (S) | 0.015b) |
| Nickel (Ni) | 8.00 - 10.50 |
| Nitrogen (N) | 0.10 |
| Iron (Fe) | Balance |
304 stainless steel Mechanical properties
| Property | Value |
|---|---|
| Comprehensive Strength | 210 MPa |
| Proof Stress | 210 Min MPa |
| Tensile Strength | 520 - 720 MPa |
| Elongation | 45 Min% |
304 stainless steel Physical Properties
| Property | Value |
|---|---|
| Density | 8,000 Kg/m3 |
| Melting Point | 1450 °C |
| Thermal Expansion | 17.2 x 10-6 /K |
| Modulus of Elasticity | 193 GPa |
| Thermal Conductivity | 16.2W/m.K |
| Electrical Resistivity | 0.072 x 10-6 Ω .m |
| Feature | Inconel 718 | 304 Stainless Steel |
|---|---|---|
| Composition | Nickel-based alloy, with high levels of nickel, chromium, molybdenum, and niobium | Primarily an iron-based alloy with a minimum of 18% chromium and 8% nickel |
| Strength | Significantly higher tensile strength at both room and high temperatures, with superior fatigue and creep resistance | Good strength for general purposes, but significantly lower than Inconel 718 |
| High-Temperature Performance | Excellent strength, oxidation resistance, and stability at very high temperatures | Strength decreases significantly at high temperatures |
| Corrosion Resistance | Superior corrosion resistance in highly aggressive and corrosive environments | Good corrosion resistance for general industrial and food-grade applications |
| Cost | Much more expensive | Significantly less expensive |
| Fabrication | More difficult to machine and work with | Easier to fabricate, weld, and form |
| Typical Applications | Aerospace, gas turbines, nuclear industry, and other high-stress, high-temperature applications | General manufacturing, medical instruments, and household products |
For 304 stainless steel, its specific heat capacity, thermal diffusivity, and thermal conductivity agree well with published data.
For Inconel 718, measurements show that its thermal conductivity is closely related to the sample's heating history and the alloy's metallurgical state.
Measurements of the solution-treated samples show thermal conductivity functions close to previously reported results, while the precipitation-treated samples exhibit higher thermal conductivity, similar to the thermal conductivity-temperature function used for comparative thermal conductivity data of Inconel 718 reference materials.
These results indicate that Inconel 718 is unsuitable as a reference material for high-precision comparative thermal conductivity measurements unless its thermal history and associated thermal conductivity function are known.
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅ Over 18 years of export experience, products sold to more than 80 countries
✅ Certified by ISO, SGS, and BV
✅ Global inventory of Inconel, Hastelloy, Incoloy, and Monel alloy tubing, plates, and bars
✅ Custom processing services available – including cutting, polishing, CNC machining, and packaging
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📦 Packaging and Shipping
All stainless steel products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel is a supplier of Inconel 718 alloy, offering a wide range of products including: seamless pipe (sizes: 4-219 mm; thickness: 0.5-20 mm); welded pipe (sizes: 5.0-1219.2 mm; thickness: 0.5-20 mm); plates (thickness: 0.1 to 100 mm; width: 10-2500 mm); strips; alloy round bars (diameter: 3-800 mm); flat bars (thickness: 2-100 mm; width: 10-500 mm); hexagonal bars (size: 2-100 mm); wire rods; and extruded profiles. We collaborate with steel mills to provide our customers with Inconel 718 alloy products that meet or exceed numerous leading industry standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS standards.
Gnee Steel stocks and sells Inconel 718, pipes, plates, strips, round bars, flat bars, forged billets, hexagonal steel, wire rods, and extruded profiles. Please feel free to contact us at ss@gneesteel.com for a quote.
