| Feature | SS304 (A2) | SS316 (A4) |
|---|---|---|
| Primary Alloying Elements | 18% Chromium, 8% Nickel | 16% Chromium, 10% Nickel, 2% Molybdenum |
| Corrosion Resistance | Excellent for general indoor/outdoor use | Superior, especially against chlorides and saltwater |
| Cost | More economical | More expensive due to Molybdenum |
| Ideal Environments | Freshwater, Architectural, Food Processing (dry) | Marine, Chemical Plants, Pharma, Salty environments |
| Tensile Strength (Class 70) | 700 N/mm² | 700 N/mm² |
The Verdict
Choose SS304 for general-purpose outdoor and indoor applications where cost is a factor. Always upgrade to SS316 if the fasteners will be exposed to saltwater, de-icing salts, or harsh chemicals.
Frequently Asked Questions
Can I mix SS304 and SS316 fasteners?
While mechanically compatible, mixing them can lead to galvanic corrosion if an electrolyte (like saltwater) is present. It is best practice to use the same grade.