304 vs 316 Stainless: Which Grade?

One of the most common questions we get is: "Should I use 304 or 316 stainless?" The short answer is: it depends on where the part lives. The longer answer involves the environment, the exposure, and what failure looks like.

304 stainless — the default

304 is the standard austenitic stainless. It's what most people mean when they say "stainless steel." It handles normal atmospheric exposure, indoor environments, kitchen and food processing areas, and general architectural use. It's the right choice for handrails, balustrades, shopfit work and indoor fixtures in most of Sydney.

304 is also the cheaper option — typically 20-30% less than 316. For interior work or dry exterior environments, there's no reason to pay more for 316.

316 stainless — the upgraded

316 has added molybdenum, which improves resistance to chloride corrosion. That matters in three situations:

• Coastal locations: Within a few kilometres of the ocean, salt in the air will eventually corrode 304. 316 resists it much better.
• Pool areas: Chlorine from pool water is tough on stainless. 316 is the right grade for pool fences and surrounds.
• Wet or washdown environments: Commercial kitchens, food processing areas with daily washdowns, and any place where stainless is regularly wet.

Which grade to use

When a client asks which grade to use, we ask where the part is going. If it's indoors in an office or shopfit, 304 is fine. If it's on a balcony overlooking the harbour, or around a swimming pool, or in a coastal suburb, we recommend 316. The extra upfront cost is far less than the cost of replacing corroded stainless work in five years.

We've seen 304 handrails go brown and rust-spotted within three years on a coastal Sydney site. That's a failure that could have been avoided by specifying 316 from the start.

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