Engineering Comparison
SS304 vs SS316 Fasteners: Detailed Engineering Comparison
Understand the critical differences between A2-70 (SS304) and A4-80 (SS316) stainless steel fasteners, their corrosion resistance, and optimal applications.
Key Differences at a Glance
| Property | SS304 (A2) | SS316 (A4) |
|---|---|---|
| Alloy Composition | 18% Chromium, 8% Nickel | 16% Chromium, 10% Nickel, 2% Molybdenum |
| Corrosion Resistance | High (General) | Very High (Marine & Chloride) |
| Tensile Strength (Class 70) | 700 MPa | 700 MPa |
| Tensile Strength (Class 80) | 800 MPa | 800 MPa |
| Cost | Base | +20-30% Premium |
| Primary Use Case | Architecture, Food processing | Marine, Chemical plants, Coastal infrastructure |
Introduction to Stainless Steel Fasteners
Stainless steel fasteners are ubiquitous in engineering due to their excellent strength and corrosion resistance. The two most common grades, SS304 (A2) and SS316 (A4), appear identical to the naked eye but behave very differently under environmental stress.
The Role of Molybdenum in SS316
The defining difference is the addition of 2-3% Molybdenum in SS316. This alloying element drastically improves resistance to pitting and crevice corrosion in chloride environments (like seawater or de-icing salts). If your project is within 5km of a coastline, SS316 is structurally mandatory.
Technical FAQ
Which is more corrosion resistant: SS304 or SS316?+−
SS316 is more corrosion-resistant due to the addition of molybdenum, making it ideal for marine environments and chemical processing. SS304 is suitable for general outdoor and food-grade applications.