Differences between Inconel 718 and SS321
Inconel 718 is a nickel-based alloy with excellent high-temperature strength, creep resistance, and extremely strong corrosion resistance; while SS321 is a titanium-stabilized austenitic stainless steel with lower strength but better corrosion resistance in general applications and lower cost. The main difference is that Inconel 718 can withstand higher temperatures, making it ideal for applications such as jet engines, while SS321 is more suitable for medium-temperature environments and general industrial uses.
What are the differences between Inconel 718 and SS304?
Inconel 718 exhibits excellent resistance to chlorides and corrosion in brine environments. Similarly, SS304 is renowned for its good corrosion resistance and superior mechanical properties. The combination of SS304 and Inconel 718 is widely used in the oil and gas industry.
Chemical Composition of Inconel 718
Typical chemical analysis of Inconel 718.
|
Element
|
Percentage |
| Carbon |
0.08 max |
| Manganese |
0.35 max |
| Phosphorus |
0.015 max |
| Sulfur |
0.015 max |
| Silicon |
0.35 max |
| Chromium |
17-21 |
| Nickel |
50-55 |
| Molybdenum |
2.80-3.30 |
| Columbium |
4.75-5.50 |
| Titanium |
0.65-1.15 |
| Aluminum |
0.20-0.80 |
| Cobalt |
1.00 max |
| Boron |
0.006 max |
| Copper |
0.30 max |
| Tantalum |
0.05 max |
| Iron |
Balance |
Physical Properties of Inconel 718
|
Solution Treated |
Solution Treated and Aged |
|
| Density |
0.296 lb/in3 (8.192 g/cm3) |
0.297 lb/in3 (8.22 g/cm3) |
| Specific Gravity |
8.19 |
8.22 |
| Melting Range |
2500-2600°F |
1370-1430°C |
Stainless 321 Chemical Composition, %
| Cr | Ni | Mo | Ti | C | Mn | Si | P | S | N | Fe | |
|---|---|---|---|---|---|---|---|---|---|---|---|
|
MIN |
17.0 |
9.0 |
– |
5x(C+N) |
– |
– |
0.25 |
– |
– |
– |
– |
|
MAX |
19.0 |
12.0 |
0.75 |
0.70 |
0.08 |
2.0 |
1.0 |
0.045 |
0.03 |
0.1 |
Bal |
Stainless 321 Mechanical Properties
| Temperature, °F | Ultimate Tensile Strength, ksi | .2% Yield Strength, ksi |
|---|---|---|
|
68 |
93.3 |
36.5 |
|
400 |
73.6 |
36.6 |
|
800 |
69.5 |
29.7 |
|
1000 |
63.5 |
27.4 |
|
1200 |
52.3 |
24.5 |
|
1350 |
39.3 |
22.8 |
|
1500 |
26.4 |
18.6 |
| Feature | Inconel 718 | SS321 |
|---|---|---|
| Base Material | Nickel-chromium alloy | Titanium-stabilized stainless steel |
| High-Temperature Strength | Excellent; used in aerospace and gas turbines | Low; suitable for medium-temperature environments |
| Corrosion Resistance | Superior, especially in extreme corrosive environments (e.g., high-temperature oxidation) | Good, but susceptible to chromium carbide precipitation in the 450-850°C range |
| Mechanical Properties | High strength and creep resistance | Good strength and formability, but lower than Inconel 718 |
| Cost | High | Lower |
| Density | Higher (8.19 g/cm³) | Lower (7.8 g/cm³) |
| Typical Applications | Aerospace, gas turbines, nuclear industry, rocket motors | General industry, food processing, construction, household products |
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
✅ Fast delivery within 7-15 days, supported by global logistics partners
📦 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.
