303 vs. 303Se Stainless Steel: What’s the Difference?
What is 303 stainless steel?
303 stainless steel is one of the most widely used alloys in the 303 series of stainless steels. It is composed of 17-19% chromium, 8-10% nickel, and 0.15-0.35% sulfur, the addition of which enhances its machinability. It offers excellent machinability and good corrosion resistance. It is often used in applications where ease of machining is important, but its corrosion resistance at high temperatures is inferior to other alloys such as 316.
What is 303Se stainless steel?
303Se is an improved version of 303 stainless steel. The "Se" in 303Se stands for selenium, which is added (approximately 0.15-0.35%) to enhance its machinability. While maintaining similar mechanical properties to 303 stainless steel, it also offers comparable corrosion resistance, making it suitable for a variety of industrial and food-grade applications.
303 vs. 303Se Stainless Steel: Key Differences
While both 303 and 303Se stainless steels are suitable for precision machining applications, the differences in chemical composition, corrosion resistance, and machinability may influence which alloy you should choose for your application.
Chemical Composition
| Element | 303 Stainless Steel | 303Se Stainless Steel |
|---|---|---|
| Carbon (C) | ≤ 0.15 | ≤ 0.15 |
| Manganese (Mn) | 2.00 - 2.50 | 2.00 - 2.50 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.20 | ≤ 0.20 |
| Sulfur (S) | 0.15 - 0.30 | ≤ 0.15 |
| Selenium (Se) | Not present | 0.15 - 0.30 |
| Chromium (Cr) | 17.00 - 19.00 | 17.00 - 19.00 |
| Nickel (Ni) | 8.00 - 10.00 | 8.00 - 10.00 |
| Iron (Fe) | Balance | Balance |
Note: The key difference in composition is the addition of selenium (0.15 - 0.30%) in 303Se, which replaces sulfur to improve corrosion resistance.
Mechanical Properties
| Property | 303 Stainless Steel | 303Se Stainless Steel |
|---|---|---|
| Tensile Strength | ≥ 520 MPa | ≥ 510 MPa |
| Yield Strength | ≥ 210 MPa | ≥ 200 MPa |
| Elongation | ≥ 40% (in 50mm) | ≥ 40% (in 50mm) |
| Hardness | ≤ 92 HRB | ≤ 92 HRB |
| Density | 7.90 g/cm³ | 7.90 g/cm³ |
| Modulus of Elasticity | 193 GPa | 193 GPa |
Key Differences Between 303 and 303Se Stainless Steel
| Property | 303 Stainless Steel | 303Se Stainless Steel |
|---|---|---|
| Machinability | Excellent; good for most machining operations | Superior to 303, ideal for high-speed machining |
| Corrosion Resistance | Good; resists corrosion in water, air, and many chemicals | Similar to 303, good for most industrial environments |
| Selenium Content | No selenium | Contains selenium to improve machinability |
| Applications | Fasteners, shafts, gears, bolts, and precision components | High-speed machining components, fasteners, medical equipment |
Gnee Steel offers a comprehensive range of AISI 303 products in a wide variety of specifications, all conforming to international standards such as ASTM, ISO, and EN. These products are commonly used in a variety of forms to meet diverse industrial applications. These include bars, rods, plates, tubes, wire, and fasteners such as bolts, nuts, and screws. For detailed chemical composition and free samples, please contact our factory today. We offer competitive pricing and excellent service.Email: info@gneestainless.com
