Stainless Steel 201 vs 304 vs 316: Nickel, Molybdenum, Magnet Test and Where to Use Each

In short, stainless steel 201 vs 304 vs 316 comes down to nickel and molybdenum. Grade 201 cuts nickel to 3.5–5.5% and replaces it with manganese, 304 is the all-round grade with 8–10.5% nickel, and 316 adds 2–3% molybdenum for better resistance to chloride corrosion such as sea air. For railings, kitchen sinks and bathroom accessories in an ordinary home, 304 is usually enough; near the coast, 316 is the safer choice.

Key Facts

• ASTM A240 composition: grade 201 (UNS S20100) Cr 16–18%, Ni 3.5–5.5%, Mn 5.5–7.5%; grade 304 (S30400) Cr 18–20%, Ni 8–10.5% (2026-11-04, source: SSINA – Composition/Properties (ASTM A240 tables)).
• Grade 316 (S31600) contains Cr 16–18%, Ni 10–14% and Mo 2–3%; its main advantage is resistance to pitting and crevice corrosion in chloride environments (2026-11-04, source: ASSDA – 316: The First Step Up).
• Minimum yield strength for sheet under ASTM A240: 260 MPa for grade 201; 205 MPa for grade 316, with 515 MPa minimum tensile strength (2026-11-04, source: SSINA – Composition/Properties (ASTM A240 tables)).
• Austenitic 304 and 316 are generally non-magnetic when annealed but can be attracted to a magnet after cold work, because part of the austenite transforms to martensite (2026-11-04, source: ASSDA – Magnetic Effects of Stainless Steels).

Stainless steel 201 vs 304 vs 316 by composition

All three are austenitic stainless steels. Their rust resistance comes from chromium, which forms a thin oxide film on the surface. The difference lies in the supporting elements. Nickel stabilises the austenitic structure and helps corrosion resistance, but it is expensive. Grade 201 therefore uses much less nickel and raises manganese and nitrogen to keep the structure austenitic.

Grade 304 is the most common grade in building products and kitchenware. Grade 316 has broadly the same mechanical properties and fabrication behaviour as 304, but its 2–3% molybdenum improves resistance to pitting and crevice corrosion, especially where chlorides are present: sea air, brackish water and some cleaning chemicals.

Quick choice by location

• Dry interiors (decorative trims, furniture frames, kick plates): 201 is often used because it costs less; keep surfaces clean.
• Kitchens and bathrooms (sinks, racks, shower poles, grab bars): 304 is a safe choice for homes.
• Coastal exteriors (balcony railings, gates, outdoor fixings): 316 is more suitable. ASSDA notes 316 is often chosen for sea-front buildings.

Why the magnet test is not proof

Many buyers hold a magnet to a product to tell 201 from 304. This is unreliable. According to ASSDA, annealed 304 and 316 are hardly attracted to a magnet, but cold working such as bending, rolling or tube drawing can turn part of the structure into magnetic martensite. A bent corner on a 304 railing may therefore pull slightly on a magnet, while annealed 201 may not pull at all. A magnet gives a rough hint, not proof of grade.

More reliable checks

• Ask for the mill certificate showing heat number, standard (for example ASTM A240 for sheet) and chemical analysis.
• For project purchases, request an XRF/PMI composition test on site or in a laboratory, and write the grade into the contract.
• Check marks on the product or packaging; a "SUS 304" or "AISI 304" label means little without documents.
• Compare actual wall thickness with the specification, since thin tube dents easily even when the grade is right.

Care that keeps stainless clean

Even 316 can stain if left dirty in salty air. Rinse outdoor surfaces with clean water regularly, avoid ordinary steel brushes that leave iron particles, and do not use strong chlorine-based cleaners. After welding, the weld area should be cleaned so that the passive film can re-form.

homeX, an integrated building materials and furniture platform in Indonesia with showroom, warehousing and delivery, can help you compare sinks, railings and stainless accessories by grade and supporting documents.

Stainless steel 201 vs 304 vs 316: related articles and products

• Stair railing prices per metre: iron, stainless and glass
• Kitchen sink prices by brand
• Hot-dip galvanizing thickness under ISO 1461
• homeX building materials catalog

FAQ

Will 201 stainless always rust? Not necessarily. 201 is still stainless steel, but its lower nickel makes it better suited to dry interiors with regular cleaning.

Is 304 stainless never magnetic? It is nearly non-magnetic when annealed, but bent or cold-rolled parts can attract a magnet slightly. A magnet test does not prove the grade.

When do I need 316? For exterior parts near the sea or in chloride environments, because 2–3% molybdenum improves pitting resistance.

For building and renovation material needs, reach the homeX team on WhatsApp +62 821 1818 998, by email at homex9998@gmail.com or through our contact page.

Sources: SSINA – Composition/Properties (ASTM A240 tables); ASSDA – 316: The First Step Up; ASSDA – Magnetic Effects of Stainless Steels