Is Steel Magnetic? Which Steels Are Not Magnetic?

Short Answer: Yes — the Vast Majority of Steels Are Magnetic

Carbon steels, alloy steels and tool steels attract a magnet. The one big exception is austenitic stainless steel (grades like 304 and 316) — in the annealed condition it does not attract. So the correct answer to "is steel magnetic?" is: it depends on the crystal structure. It is not the iron content that decides, but how the atoms are arranged.

Why Magnetic? The Origin of Ferromagnetism

Pure iron is ferromagnetic: the magnetic moments of its atoms align in parallel within local domains and respond strongly to an external magnet. Steel inherits this property of iron as long as the crystal structure allows it:

• Ferrite (BCC — body-centred cubic): ferromagnetic ✅ — the main phase of carbon steels at room temperature
• Martensite (BCT): ferromagnetic ✅ — the phase of quenched/hardened steels
• Austenite (FCC — face-centred cubic): NOT magnetic ❌ — the atomic arrangement prevents the moments from aligning

Ordinary carbon steel at room temperature consists of ferrite + pearlite → it attracts a magnet. From S235JR structural steel to C45 medium-carbon steel, every grade we stock belongs to this group.

Which Steel Is Magnetic, Which Is Not? (table)

Steel type	Example	Structure	Magnetic?
Carbon steel	S235JR, C45	Ferrite + pearlite	✅ Yes, strongly
Alloy Q&T steel	42CrMo4, 34CrNiMo6	Tempered martensite	✅ Yes, strongly
Free-cutting steel	11SMn30	Ferrite + pearlite	✅ Yes
Ferritic stainless	430 (1.4016)	Ferrite	✅ Yes
Martensitic stainless	420 (1.4021)	Martensite	✅ Yes
Duplex stainless	2205 (1.4462)	Ferrite + austenite	✅ Yes (partly)
Austenitic stainless	304 (1.4301), 316 (1.4404)	Austenite	❌ No (annealed)

As the table shows, the statement "stainless steel is not magnetic" is wrong — only the austenitic family of stainless steels isn't. Ferritic and martensitic stainless grades are thoroughly magnetic. To read which family a grade belongs to from its composition, use our Chemical Composition tool; for cross-standard designations, see the Steel Grade Equivalents tool.

Why Does 304 Stainless Sometimes Attract a Magnet?

A common surprise: "the 316 spoon didn't attract, but the 304 tube does, slightly?" The cause is cold working. Austenitic stainless partially transforms into deformation martensite during bending, drawing or rolling — and martensite is magnetic. Hence:

• The same 304 material: non-attracting as annealed sheet, slightly attracting as hard-drawn tube or wire
• 316 is more resistant to this transformation thanks to its nickel/molybdenum balance — it usually stays "deader"
• The remedy is annealing: after solution annealing, the magnetism disappears again

So slight magnetism is not a quality defect — it is a trace of the manufacturing history.

Temperature Effect: the Curie Point

Magnetism is not a permanent property either. Iron loses its ferromagnetism at ~770 °C (the Curie temperature) — thermal vibration destroys the ordering of the atomic moments. Red-hot steel does not attract a magnet; it regains the property on cooling. Blacksmiths and heat treaters know this behaviour well, and it is also accounted for in induction-heating design.

What the Magnet Test Tells You — and What It Doesn't

The workshop magnet is a handy first screen, but know its limits:

• ✅ It tells you: If the part (in annealed condition) does not attract, it is most likely austenitic stainless or a non-ferrous metal.
• ❌ It does not tell you: Whether an attracting part is carbon steel, alloy steel, ferritic stainless or cast iron. They all attract — distinguishing them takes spark/chip tests or analysis; see our cast iron vs cast steel guide for details.
• ❌ It does not tell you: The grade. No magnet can tell 304 from 316 or S235 from C45 — positive identification requires spectral analysis (PMI).

Supply from Aktif Çelik

The carbon steels, bright (cold-drawn) bars and free-cutting steels stocked by Aktif Çelik are ferromagnetic grades — fully compatible with magnetic lifting, magnetic separation and induction heating in your processes. Contact our technical team for grade selection, 3.1 certificates and cutting to size.