What grades of stainless steel are non-magnetic?

When most people think of stainless steel, they picture a tough, shiny, rust-resistant metal used in everything from kitchen appliances to skyscrapers. But there’s one detail that often surprises many: not all stainless steels are magnetic.

What Makes Stainless Steel Magnetic or Non-Magnetic?

The magnetism in stainless steel comes down to its crystal structure – the arrangement of atoms inside the metal. Stainless steels are generally grouped into three main families based on their structure:

1. Austenitic Stainless Steels – Non-magnetic

2. Ferritic Stainless Steels – Magnetic

3. Martensitic Stainless Steels – Strongly Magnetic

Only austenitic stainless steels can be considered non-magnetic. This is an inherent property of their microstructure but is a useful property for a number of specific applications.

Can Stainless Steel Become Magnetic Over Time?

Yes, but only slightly – and only certain grades.

When austenitic stainless steels like 304 are cold worked (through bending, stamping, or rolling), some of the metal’s structure changes from austenite (non-magnetic) to martensite (magnetic). This can give the steel a weak magnetic pull.

However, the corrosion resistance is unaffected. Additionally, the magnetism can often be reduced by annealing (heating and cooling) to restore the original crystal structure.

So if your 304 steel sink attracts a magnet, don’t worry – it doesn’t mean it’s low quality. It just means it’s been shaped or formed during manufacturing.

Applications of Non-Magnetic Stainless Steels

Non-magnetic stainless steels are essential in industries and applications where magnetism could cause interference or safety issues.

1. Medical and Scientific Equipment
2. Marine and Coastal Environments
3. Electronics and Electrical Equipment
4. Chemical and Food Processing
5. Architecture and Design

Got any Questions? Contact us Today

If you have any questions about the magnetic properties of stainless steel, please get in touch today.