SS 304 and SS 316 are the two stainless steel grades we sell most. Both are austenitic, non-magnetic and easy to weld, and from across the room they look the same. The difference is in the chemistry, and it decides how long your equipment lasts.
The key difference: molybdenum
SS 304 contains about 18% chromium and 8% nickel. SS 316 has slightly less chromium (16–18%), more nickel (10–14%) and, most importantly, 2–3% molybdenum. Molybdenum greatly improves resistance to chlorides — salt, sea water, bleach, brine and many process chemicals — which cause pitting and crevice corrosion in 304.
| Property | SS 304 | SS 316 |
|---|---|---|
| Chromium | 17.5 – 19.5% | 16 – 18% |
| Nickel | 8 – 10.5% | 10 – 14% |
| Molybdenum | — | 2 – 3% |
| Tensile strength (min) | 515 MPa | 515 MPa |
| Chloride resistance | Moderate | Good |
| Typical price | Base | Roughly 40–70% higher per kg |
When SS 304 is the right choice
- Commercial kitchen equipment, sinks and food counters
- Dairy tanks and general food processing (without brine)
- Indoor architectural work, railings and furniture
- Water tanks and general fabrication
When you should pay for SS 316
- Pharma and API plants — most pharma drawings specify 316L for product-contact parts
- Chemical plants handling chlorides, acids or solvents
- Coastal and marine installations — Dahej, Bharuch, Hazira and other sea-side sites
- Swimming pools, effluent treatment plants and anything exposed to bleach
What about 304L and 316L?
The "L" grades have carbon below 0.03%. Low carbon prevents chromium carbides forming at weld zones, which would otherwise reduce corrosion resistance next to the weld. Most mills now supply dual-certified 304/304L and 316/316L material, so you get both properties in one.
How to tell 304 from 316 on site
A magnet won't help — both are non-magnetic. The reliable way is the mill test certificate that comes with the material, backed by a PMI (positive material identification) test with a handheld XRF gun. Every sheet, pipe and bar we supply comes with its MTC; PMI can be arranged on request.
Our advice
If the material will see salt, chlorides or acids, buy 316/316L — the extra cost is small compared with replacing corroded equipment. For everything else, 304 gives excellent value. Not sure? Send us the application and we will suggest the right grade.