Materials explained

SUS304 vs SUS201 Stainless Steel in Bathroom Hardware

"Stainless steel" on a hardware specification covers two very different alloys in common use. One holds up in a humid bathroom for years; the other can show rust spots within a couple of seasons and is difficult to tell apart by eye. The difference is nickel, and it is invisible until it is not. This guide explains the two grades, why they behave differently, why the magnet test is not a verification, and how to specify and confirm the grade.

Published September 23, 2026Last updated September 23, 2026

The short answer

Quick Reference

Point 01: 304 is the standard austenitic grade: roughly 18–20% chromium and 8–11% nickel, with good corrosion resistance in wet, humid environments.
Point 02: 201 replaces part of that nickel with manganese and nitrogen — typically around 16–18% chromium, 3.5–5.5% nickel and 5.5–7.5% manganese — which lowers cost and lowers corrosion resistance.
Point 03: Both are non-magnetic in principle, but cold working can make either slightly magnetic, so a fridge magnet is a rough indicator at best, not a verification.
Point 04: A mill certificate or a spectrometer test identifies the grade; "stainless" on a quotation does not.
Point 05: Specify the grade by number per component, and confirm it model by model rather than assuming it across a range.

Roller and running gear of a sliding shower door

Start here

The Same Word, Two Alloys

Stainless steel resists corrosion because chromium in the alloy forms a thin, self-repairing oxide layer on the surface. Nickel stabilizes the alloy's structure and improves that resistance, particularly in wet and humid conditions. Nickel is also the expensive ingredient, and the 200-series grades exist because manganese and nitrogen can substitute for part of it at lower cost. In a dry interior the difference may never show; in a bathroom — humid, cleaned with chemicals, splashed daily — it usually does.

Chromium forms the protective oxide layer
Nickel improves resistance in wet, humid conditions
201 substitutes manganese and nitrogen for part of the nickel to cut cost

Composition and Behavior

Black frame corner and glass panel joint

Grade 304 is the general-purpose austenitic stainless steel, with a composition of roughly 18–20% chromium and 8–11% nickel by weight. It is widely used for kitchen and bathroom hardware precisely because it tolerates moisture, mild chemicals and daily cleaning without staining. Grade 201 belongs to the 200 series, in which manganese and nitrogen replace part of the nickel; typical figures are around 16–18% chromium, 3.5–5.5% nickel and 5.5–7.5% manganese. The lower nickel content makes it noticeably cheaper and noticeably less resistant to corrosion, so that in a humid bathroom, particularly where cleaning chemicals or chloride-bearing water are involved, 201 hardware is more prone to surface rust and pitting than 304. Neither grade is marine-grade — that is 316, with added molybdenum — but for interior bathroom hardware 304 is the grade normally specified.

304: ~18–20% chromium, ~8–11% nickel; good resistance in humid use
201: ~16–18% chromium, ~3.5–5.5% nickel, ~5.5–7.5% manganese; cheaper, less resistant
Chlorides and cleaning chemicals widen the gap in bathroom conditions
316 is the higher, molybdenum-bearing grade for harsher environments

Why the Magnet Test Fails

The folk test — a magnet sticks to the cheap grade and not to the good one — is unreliable in both directions. Both 304 and 201 are austenitic and non-magnetic in their annealed state, and both can become slightly magnetic where they have been cold worked: stamped, bent, drawn or machined, which describes most hardware. A magnet that sticks weakly to a handle tells you it was cold worked, not which alloy it is. The reliable methods are documentary and analytical: a mill test certificate for the material batch, or a spectrometer test — handheld XRF analyzers are common in inspection — on the finished part. Either can be requested from a supplier or performed by a third-party inspector.

Both grades are non-magnetic when annealed and can be slightly magnetic when cold worked
A magnet indicates working, not alloy
Mill certificates and spectrometer (XRF) tests identify the grade

Specifying and Confirming the Grade

Glass-to-glass connector and bracket detail

Write the grade by number — 304 — against each component that is meant to be stainless, rather than "stainless steel" generally, and be specific about which components that covers: hinges, clamps, handles, towel bars, screws and fixings, and the profiles or channels of an enclosure may each be a different material and grade. Ask the supplier to confirm the grade per model, not per range, because hardware ranges commonly mix grades between visible and hidden parts. Then confirm: a mill certificate for the batch, or a spot XRF test during pre-shipment inspection on the parts that matter most. In a hotel or a coastal property, the cost of that check is trivial against the cost of replacing rusted hardware in a hundred rooms.

WNS Global confirms hardware material and grade model by model on the specification and drawing, rather than claiming one grade across every enclosure or fitting, and the grade stated is the one an inspection can test against.

Specify "304" per component, not "stainless" per product
List every component the grade applies to, including fixings
Confirm per model, not per range
Verify with a mill certificate or XRF test at inspection

Common questions

Stainless Steel Questions

Answers to the checks buyers most often make before using this guide for a project or sourcing decision.

What is the main difference between 304 and 201 stainless steel?

Nickel content. 304 has roughly 8–11% nickel; 201 replaces much of it with manganese and nitrogen, typically leaving around 3.5–5.5% nickel. That makes 201 cheaper and less corrosion-resistant.

Will 201 hardware rust in a bathroom?

It is markedly more prone to surface rust and pitting than 304 in humid conditions, especially with cleaning chemicals or chloride-bearing water. It may look identical when new.

Can I use a magnet to tell them apart?

Not reliably. Both are non-magnetic when annealed and both can become slightly magnetic when cold worked, which most hardware is. A magnet indicates working, not alloy.

How do I verify the grade?

Request a mill test certificate for the material batch, or have a spectrometer (XRF) test performed on the finished parts during pre-shipment inspection.

Is 316 better for bathrooms?

316 adds molybdenum for higher resistance and is used in marine and harsher environments. For interior bathroom hardware, 304 is the grade normally specified; 316 is a consideration for coastal or aggressive-water settings.

Does WNS Global use 304 on all its hardware?

The material and grade are confirmed model by model on the specification and drawing rather than claimed across every product. Ask for the grade on the specific hardware in your order, and it can be verified at inspection.

In short

Specify 304 by Number, Then Verify It

304 and 201 are both "stainless steel" and behave very differently in a bathroom, because 201 trades nickel for manganese to cut cost and loses corrosion resistance with it. The magnet test cannot separate them reliably. Specify the grade by number per component, confirm it per model, and verify it with a mill certificate or an XRF test at inspection.

Nickel is the difference
201 looks the same new and rusts sooner
Magnets indicate cold work, not alloy
Mill certificate or XRF verifies the grade

Verification sources

Official Sources and Further Reading

Material performance depends on the exact grade, construction, finish, use environment and test method. Confirm the material specification and any applicable test report for the exact supplied model before final selection.

Specifying hardware for a humid or coastal project?

Talk to WNS Global

Tell us the environment and the hardware involved, and we will confirm the material and grade per component on the drawing and arrange verification at inspection where the project needs it.