304 vs 316 stainless: which grade do you actually need?

The short answer

Grade 304 suits most indoor and general-purpose parts. Grade 316 contains molybdenum, which gives better resistance to chlorides — salt, de-icing chemicals and many cleaning agents. If a part will face coastal air, swimming pools, harsh wash-downs or pharmaceutical cleaning, 316 is usually the safer choice.

How they compare

• Corrosion: 316 resists pitting from chlorides far better than 304.
• Cost: 316 is typically noticeably more expensive, so specifying it everywhere adds cost with no benefit indoors.
• Cutting and bending: both laser cut and fold in a very similar way.
• Welding: both weld well with TIG; the correct filler wire should match the grade.
• Finish: both can be grained, satin polished, mirror polished or electropolished.

Choosing for your project

Think about where the part will live and how it will be cleaned. Food, pharmaceutical and outdoor coastal equipment often justify 316; machine guards, indoor enclosures and architectural trim usually do not. If you're unsure, tell us the environment and we'll recommend a grade when we quote.