304 vs 316 Stainless Steel Door Hardware: Which Do You Need?
Written by the Prime Hardware showroom team, Annangrove NSW · Last updated 11 August 2026
316 stainless steel contains 2–3% molybdenum, which resists the chloride attack that causes pitting and corrosion in salt air. 304 does not. Choose 316 — marine grade — for any door within roughly one kilometre of breaking surf, for estuarine and harbourside sites, and for indoor pool areas. Choose 304 for everything else, including bathrooms, laundries and general external doors well inland. Both grades still need washing in coastal air.
That's the decision in a nutshell. Below: what the grades actually differ in, how to work out which zone your build sits in, and the thing that causes most customer complaints on coastal jobs — tea staining, which is usually a maintenance issue rather than a product fault.
The metallurgy, briefly
Both 304 and 316 are austenitic stainless steels. Both contain chromium, which forms the passive oxide layer that makes stainless "stainless," and nickel, which gives the steel its structure and formability. In a door hardware context they machine similarly, finish similarly and feel identical in the hand.
The difference is molybdenum. 316 adds 2–3%; 304 has none. Chloride ions — from sea spray, salt air, pool chemicals — attack the passive layer at weak points, causing pitting corrosion and, in tight gaps, crevice corrosion. Molybdenum stabilises that passive layer against chloride specifically. That single addition is what separates a handle that survives twenty years on a beachfront entrance from one that pits within two.
You'll also see the grades written as A2 (304) and A4 (316) on fixings and fasteners. Same steels, different naming convention.
Which grade for which location
| Location | Grade | Why |
|---|---|---|
| Within ~1km of breaking surf | 316 | Airborne salt is continuous. 304 will pit. |
| Harbourside and estuarine sites | 316 | Salt exposure without surf is still chloride exposure. |
| Indoor pool halls and spa rooms | 316 | Chloramines concentrate in still, humid air — harsher than most people expect. |
| External doors, inland suburbs | 304 | Rain and humidity aren't the problem. Chlorides are. |
| Bathrooms, ensuites, laundries | 304 | Fresh water and steam pose no chloride risk. |
| General internal doors | 304 | 316 is unnecessary cost indoors. |
For a more formal assessment, AS 4312 classifies Australian atmospheric corrosivity into zones — broadly, C1–C2 for benign inland environments through to C5 for severe marine. Architects and specifiers on commercial work will often nominate the zone in the specification. For residential work, the distance-from-surf rule above is the practical shortcut, and if a site sits on the boundary, specify 316: the price difference on a handful of doors is small against the cost of replacing corroded hardware on a finished home.
Tea staining: what it is and why it isn't a fault
Tea staining is the brown or orange surface discolouration that appears on stainless steel in coastal environments. It looks like rust, which is why it generates complaints, but it is a cosmetic surface phenomenon rather than structural corrosion — the steel underneath is sound and the hardware continues to function normally.
Two factors drive it. The first is surface finish. Smoother surfaces shed chloride; rougher surfaces trap it. The Australian Stainless Steel Development Association recommends a surface roughness of Ra 0.5 micrometres or better for coastal exposure, which in practice means a fine brushed, polished or electropolished finish rather than a coarse brushed one.
The second is rain washing, and it works counterintuitively. Hardware sheltered under an eave, portico or awning stains worse than fully exposed hardware, because salt accumulates with nothing to rinse it away. A front door under a deep verandah is a higher-risk position than a gate in the open.
Within roughly 200 metres of breaking surf, even 316 will tea stain without maintenance. That is normal and expected, and it's why every stainless manufacturer's coastal warranty is conditional on cleaning.
Maintenance: the part that protects your warranty
Washing coastal stainless is simple and takes minutes. Use warm water with a mild detergent, a soft cloth or sponge, then rinse with fresh water and dry. Never use steel wool, wire brushes, abrasive pads or chlorine-based cleaners — steel wool leaves carbon steel particles embedded in the surface that rust and stain the hardware permanently.
As a frequency guide: monthly within about 200 metres of surf, quarterly within one kilometre, and every six months in mild coastal areas. Sheltered hardware that never gets rained on should be washed on the shorter interval for its zone, not the longer one.
A note on finish names versus material
This trips up a lot of buyers. "Stainless Steel," "Satin Stainless" and similar names are sometimes used as finish descriptions on hardware made from brass or zinc with a plated or coated surface. A handle described as having a stainless finish is not the same thing as a handle manufactured from 316 stainless steel, and it will not perform the same way in salt air.
If you're buying for a coastal project, look for the material grade stated explicitly — "316 marine grade stainless steel construction" or similar — rather than relying on the finish name. If a listing doesn't state the grade, ask before ordering.
Frequently asked questions
What is the difference between 304 and 316 stainless steel?
Can I use 304 stainless steel door hardware near the beach?
Why is my stainless steel door handle turning brown?
Does 316 stainless steel rust?
How often should I clean coastal door hardware?
Is marine grade the same as 316?
Building or renovating on the coast? Call 1800 329 028 or visit our Annangrove showroom — we'll confirm which of our ranges are genuine 316 construction and which manufacturer warranties apply to your zone before you commit to a whole house of hardware. Browse stainless steel door hardware and entrance pull handles.
Related guide: Door Handle Backset Guide: How to Measure and Choose