How microstructure controls magnetism

Release time:

2025-11-04

Let’s keep it simple: stainless steel’s magnetism comes down to crystal structure. Austenitic grades (like 304 and 316) have a face-centered cubic structure that’s normally non-magnetic in the annealed state. Ferritic and martensitic grades (e.g., 430 or 410) have body-centered structures and are magnetic. Duplex steels sit in-between — partially magnetic because they combine austenitic and ferritic phases. Think of it like coffee blends: some are smooth and mellow (non-magnetic austenitic), others are bold and gritty (magnetic ferritic/martensitic).

Why some austenitics can become slightly magnetic

Cold working or welding can introduce a bit of magnetism to austenitic steels by transforming some austenite into martensite. It’s usually minor, but it matters in precision uses (like sensors or medical devices). So if your design must be strictly non-magnetic, specify controls for processing and test for residual magnetism.

Choosing grades by application (practical tips)

If you need magnetic material for electromagnetic assemblies or magnetic shielding, ferritic or martensitic stainless steels are your go-to. For non-magnetic needs — food equipment, lab instruments, or marine components where pick-up of particles is a concern — austenitic grades like 304/316 are better. Duplex gives you a middle ground: extra strength with moderate magnetism and improved corrosion resistance.

Xinzhonglian Steel — helping you match grade to need

At Xinzhonglian Steel, we guide you through magnetic spec requirements, offer certified test reports, and supply the right stainless grade for your environment and manufacturing process. Tell us whether magnetism matters in your design, and we’ll recommend grades and processing routes that meet function and compliance.

Magnetism in stainless steel isn’t mysterious — it’s metallurgy. Pick the right microstructure, and your part will behave exactly as you expect.

If you have any questions regarding steel products, please contact Xinzhonglian.