PROGRÈS
304 vs 316 Acier inoxydable: Key Differences for Tubes, Plates and Bars
304 et 316 are the two most popular grades of austenitic stainless steel. They look almost identical, but the addition of molybdenum in 316 makes a significant difference in corrosion resistance, especially in chloride and salt-water environments. This article explains the key differences between 304 et 316 stainless steel for tubes, plates and bars, and helps you decide which grade your project really needs.
304 vs 316: Key Differences
| Item | 304 | 316 |
|---|---|---|
| Chrome (Cr) | 18.0 – 20.0% | 16.0 – 18.0% |
| Nickel (Dans) | 8.0 – 11.0% | 10.0 – 14.0% |
| Molybdenum (Mo) | None | 2.0 – 3.0% |
| Tensile strength | >= 515 MPa | >= 515 MPa |
| Yield strength | >= 205 MPa | >= 205 MPa |
| Chloride resistance | Good | Excellent |
| Relative cost | Lower | Higher (approx. 20-30%) |
| Typical applications | Food equipment, ustensiles de cuisine, architectural, general industry | Marin, chimique, pharmaceutique, médical, offshore |
304 Acier inoxydable: The General-Purpose Grade
304 is the most widely used stainless steel grade in the world. Avec 18% chrome et 8% nickel, it offers good corrosion resistance, excellent formability and weldability, and reliable mechanical properties with a tensile strength of at least 515 MPa. It performs well in atmospheric, food and mild chemical environments, which is why it dominates applications such as kitchen equipment, préparation des aliments, beverage tanks, architectural decoration and general piping. For most indoor and general outdoor applications, 304 is the most cost-effective choice.
316 Acier inoxydable: The Marine and Chemical Grade
316 adds 2-3% molybdenum to its chromium-nickel base, which dramatically improves resistance to pitting and crevice corrosion in chloride environments. It also maintains higher strength and creep resistance at elevated temperatures. This makes 316 the standard choice for marine hardware, coastal structures, équipement de traitement chimique, pharmaceutical machinery, medical implants and heat exchangers where 304 would eventually pit or rust.
How to Choose Between 304 et 316
- For indoor, nourriture, beverage or general industrial use, 304 is sufficient and more economical.
- For marine, coastal, offshore or chloride-exposed environments, always choose 316.
- For chemical, pharmaceutical and medical applications, 316 is the safer choice.
- For decorative and architectural purposes, both grades can be supplied with brushed or mirror finishes.
- 316L (low carbon) is recommended when welding thick sections to avoid sensitization and intergranular corrosion.
Conclusion
The choice between 304 et 316 comes down to the working environment: 304 covers most general applications at a lower cost, while 316 provides superior corrosion resistance where chlorides, chemicals or salt water are present. QIDAMT supplies both 304 et 316 stainless steel tubes, plates, bars, strips and coils with mill test certificates, competitive prices and prompt delivery. Contact us for a quote today.
