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Is SS 316 better than SS 304?
Short answer
SS 316 is better than SS 304 wherever chlorides are present, because its 2–3% molybdenum raises pitting resistance (PREN about 24 against 19). For dry, indoor and food-contact service without salt, SS 304 performs the same at a lower price, so "better" depends entirely on the environment.
SS 304 vs SS 316 at a glance
| Property | SS 304 | SS 316 |
|---|---|---|
| UNS | S30400 | S31600 |
| EN | 1.4301 | 1.4401 |
| Family | Austenitic stainless steel | Austenitic stainless steel |
| C (%) | 0.07 max | 0.08 max |
| Cr (%) | 17.5 – 19.5 | 16.0 – 18.0 |
| Ni (%) | 8.0 – 10.5 | 10.0 – 14.0 |
| Mo (%) | — | 2.00 – 3.00 |
| N (%) | 0.10 max | 0.10 max |
| Tensile strength | 515 MPa (75 ksi) | 515 MPa (75 ksi) |
| Yield strength | 205 MPa (30 ksi) | 205 MPa (30 ksi) |
| PREN | 18 – 20 | 23 – 25 |
| Density | 7.93 g/cm³ | 8 g/cm³ |
| Magnetic | Essentially non-magnetic when annealed; cold work can make it slightly magnetic. | Essentially non-magnetic when annealed; cold work can make it slightly magnetic. |
| Typical use | Food, dairy and beverage processing equipment | Chemical and petrochemical process equipment |
Which should you choose?
There's no universal "winner": the right choice depends on service conditions, codes and cost. Share your conditions with us for a recommendation.
The coastal rule of thumb
Within a few kilometres of the sea, or wherever de-icing salts, brines or chlorinated water touch the surface, specify SS 316/316L. Inland, indoors and in clean water, SS 304/304L is normally enough. Tea staining on SS 304 railings near the coast is the classic sign the wrong grade was chosen.
Telling them apart on site
The two look identical and are both non-magnetic when annealed. Only a molybdenum check by PMI separates them reliably, which is why mixed stock is a common receiving problem.
Products in both grades
Related guides, comparisons and articles
Guides
Frequently asked questions
How much more does SS 316 cost than SS 304?
Typically 20–40% more per kilogram, depending on nickel and molybdenum prices at the time of order.
Is SS 316 food grade?
Both SS 304 and SS 316 are widely used for food contact. SS 316 is chosen for salty or acidic foods and for cleaning with chloride-containing chemicals.
What is the main difference between SS 304 and SS 316?
SS 316 adds 2–3% molybdenum and more nickel to the SS 304 base, raising pitting resistance (PREN about 24 against 19) for chlorides, marine air and many acids. SS 304 is cheaper and performs equally well in dry, indoor and mildly corrosive service.
When should I choose SS 304?
Indoor, food, water and general fabrication where chlorides are low.
When should I choose SS 316?
Coastal, marine, chemical and pharmaceutical service, or wherever chlorides are present.
Can SS 304 replace SS 316?
Only when the design, code and specification allow it. Strength, corrosion resistance and temperature limits differ, so substitution must be approved by the design authority.
Which has better pitting resistance, SS 304 or SS 316?
Typical PREN: SS 304 18 – 20, SS 316 23 – 25. A higher PREN generally means better chloride pitting resistance.