Stainless Steel 304 vs 201 vs 316
Why Stainless Rusts (2026)

What makes steel ‘stainless’

Stainless steel is ordinary iron-based steel with chromium added. Once there is 10.5% chromium or more, the surface forms a thin, invisible chromium oxide film, called the passive film. That film is what stops rust, and when it is scratched it heals itself as long as oxygen can reach the surface. Nickel and molybdenum are added on top to make the film tougher in harsher conditions.

The important word is resistant. Stainless steels are corrosion-resistant, but they are not completely impervious to rusting. Whether a sink, a grille or a railing stays bright in a Malaysian home depends on two things: which grade was used, and what it is exposed to. Most “my stainless is rusting” complaints come down to the wrong grade for the place, or something other than the steel itself.

The three grades you will be quoted: 201, 304 and 316

• 304 is the most common stainless steel in the world, the classic ‘18/8’ (around 18% chromium, 8% nickel). It belongs to the 300 series, the largest and most widely used group. This is the normal grade for kitchen sinks, cabinets, railings, grilles and water pipes.
• 201 is a 200 series grade: an inexpensive stainless with low nickel, where manganese and nitrogen are used to replace much of the nickel. It looks the same as 304 when new and costs less, which is why it turns up in budget sinks, grilles, furniture and fittings.
• 316 is the second most common grade. It adds molybdenum, which gives it better resistance to chlorides (salt). It is known as marine grade and is the grade used near the sea, around pools and in harsher chemical conditions.

On fasteners you may see these as A2 (the 304 family) and A4 (the 316 family) stamped on the head of a bolt.

What is in each grade

The pattern is clear from the table. 304 has more chromium and roughly twice the nickel of 201. 316 keeps the nickel and adds molybdenum. Adding nickel and molybdenum are two of the recognised ways to raise corrosion resistance, so the ranking for rust resistance runs 201, then 304, then 316.

Why 201 marks and rusts sooner

201 is not fake stainless. It is a real, standardised grade, and indoors in a dry room it can look fine for years. The problem is margin. With less nickel and a lower chromium floor than 304, its passive film is less robust, so it gives up sooner when the conditions get harder: wet kitchens, bathrooms, cleaning chemicals, salty air. Our kitchen sink and tap guide puts it plainly: the cheaper 201 grade is less corrosion-resistant than 304. The stainless vs aluminium cabinet guide adds that 201 is more prone to surface tea-staining and pitting in humid, coastal or chlorinated air.

So a 201 sink in a busy wet kitchen, a 201 grille facing the rain, or a 201 railing by the sea will usually show brown spots long before a 304 one does. That does not mean 201 is never right — for a dry, indoor, decorative item it can be sensible value — but it should be a choice you make knowingly, not a substitution you discover later.

Near the coast: tea staining, pitting and 316

Salt is the enemy. Localised corrosion of stainless is most common where chloride ions are present, and in Malaysia that means homes near the sea, such as Port Klang, Klang and Sepang, plus anything near a salt-chlorinated pool. The first sign is usually tea staining: a light brown discolouration on the surface, often where rain does not wash the steel. Left alone it can turn into small, deep pits.

304 is subject to pitting and crevice corrosion in warm chloride environments, and when it is too sensitive the usual step up is 316, whose molybdenum gives greater resistance to attack by chlorides. That is why the grille door price guide recommends SS316 near the sea. For outdoor items at the coast, 316 is the grade to ask for; for 201 outdoors at the coast, expect staining.

Rust that is not the steel’s fault

Before blaming the grade, check for these. They cause brown marks even on good 304:

• Steel wool and carbon-steel dust. Iron particles from a steel wool pad, a wire brush, or grinding dust from nearby mild steel work sit on the surface and rust. It looks like the stainless is rusting, but it is contamination on top.
• Crevices and trapped dirt. Chlorides concentrate in tight gaps: under a washer, where two plates overlap, under a rubber mat on a counter, or under grime that is never cleaned. Starved of oxygen, the passive film cannot heal there.
• Mixed metals. Stainless in contact with aluminium or galvanised steel in wet, salty conditions sets up galvanic corrosion, and the less noble metal, the aluminium or the zinc coating, corrodes around the joint.
• Harsh cleaners. Chloride-based cleaners and bleach left on the surface attack the passive film. Rinse after using them.

The magnet test myth

The most common advice in hardware shops is to hold a magnet to the steel: ‘if it sticks, it is not real stainless’. It does not work the way people think.

• 304 and 316 are austenitic stainless steels, which are usually non-magnetic. But 201 is austenitic too, so it is also essentially non-magnetic. A magnet cannot tell 201 from 304 — the exact substitution most buyers are worried about.
• Austenitic grades can become slightly magnetic where they have been bent, pressed or cold-worked, so a corner of a genuine 304 sink or a bent railing post can pull a magnet a little.
• Ferritic and martensitic stainless steels are magnetic and are still stainless; ferritic grades are used for items such as exhaust pipes and building components, and martensitic grades for tools and wear-resistant parts.

Telling 201 from 304 needs a composition test, not a magnet. The practical defence is simpler: get the grade written on the quotation and the invoice, so a substitution becomes a documented breach rather than an argument.

Which grade where in a Malaysian home

What stainless costs on existing ClickBina guides

Grade is one of the biggest reasons two stainless quotes differ. These indicative 2026 Klang Valley figures are from other ClickBina guides; they show the stainless option next to its alternatives:

A price well below these ranges for ‘stainless’ is a reason to ask which grade it is. For commercial kitchens, where grade and thickness matter even more, see the commercial kitchen setup guide.

Keeping stainless looking right

1. Wipe along the grain with a soft cloth and mild detergent; never use steel wool or a wire brush.
2. Rinse off bleach and chloride cleaners; do not leave them sitting on the steel.
3. Outdoors near the sea, rinse grilles and railings with fresh water now and then, especially the parts the rain never reaches.
4. Deal with light tea staining early with a non-scratch stainless cleaner before it turns into pits.
5. Keep aluminium and stainless apart with a washer or spacer where they meet outdoors.

How ClickBina handles stainless items

Sinks, cabinets, grilles, railings and gutters are part of the whole-house refurbishment work ClickBina coordinates as an experienced KL & Selangor contractor, so replacing a rusting sink or grille can be done together with the rest of the work. Whoever does the job, ask for the grade of every stainless item in writing on the quotation, matched to the place: 304 for normal indoor and outdoor use, 316 where the sea or a pool is close. Our price is flat, with no hidden charges. A site visit is RM150, waived if you go ahead. WhatsApp us your job details and we reply within the hour.

Sources & methodology

The chromium threshold, the passive film, the 200 and 300 series, magnetism and chloride pitting are from the Wikipedia article on stainless steel. Grade descriptions are from the Wikipedia list of SAE steel grades. The 201 composition and the 200 series structure are from the Wikipedia article on austenitic stainless steel; the 304 composition, the A2 designation and its chloride limits are from the article on SAE 304; the 316 composition, the A4 equivalence and marine use are from the article on SAE 316L. Mixed metal corrosion is from the article on galvanic corrosion and the note that stainless is not impervious to rust is from the article on passivation. Prices are quoted from the ClickBina guides named in the table; they are indicative, and every job is priced after seeing it.