304 stainless steel is one of the most widely used stainless steel grades around the world. Known for its excellent corrosion resistance, good formability, and affordability, it is found in applications ranging from kitchen equipment to industrial components. But one common question from engineers and end users is: Is 304 stainless steel magnetic?
In this article, sakysteel explores the magnetic behavior of 304 stainless steel, what affects it, and what it means for your project or product selection.
304 stainless steel is an austenitic stainless steel composed primarily of:
18% chromium
8% nickel
Small amounts of carbon, manganese, and silicon
It is part of the 300-series stainless steel family and is also known as AISI 304 or UNS S30400. It is prized for its corrosion resistance in a wide variety of environments, including food processing, marine applications, and architectural structures.
304 stainless steel is generally considered non-magnetic in its annealed (softened) state. This is due to its austenitic crystal structure, which does not support magnetism like ferritic or martensitic steels do.
However, certain conditions can induce magnetism in 304 stainless steel, especially after mechanical processing.
When 304 stainless steel is bent, stamped, rolled, or drawn—common processes in manufacturing—it undergoes cold working. This mechanical deformation can cause a portion of the austenite to transform into martensite, a magnetic structure.
As a result, parts like wire, springs, or fasteners made from 304 may show partial or full magnetism depending on the degree of cold work.
Some welding processes may also locally change the structure of 304 stainless steel, especially near heat-affected zones, making those areas slightly magnetic.
In rare cases, residual iron particles or contaminants from machining tools can give a magnetic response, even if the bulk material is not magnetic.
| Grade | Structure | Magnetic? | Notes |
|---|---|---|---|
| 304 | Austenitic | No (but may become slightly magnetic after cold work) | Most common grade |
| 316 | Austenitic | No (even more resistant to magnetism than 304) | Marine grade |
| 430 | Ferritic | Yes | Magnetic and lower corrosion resistance |
| 410 | Martensitic | Yes | Hardenable and magnetic |
In most cases, a small magnetic response is not a defect and does not affect corrosion resistance or performance. However, if you’re working in industries where magnetic permeability must be controlled—such as electronics, aerospace, or MRI environments—you may need fully non-magnetic material or further processing.
At sakysteel, we provide both standard and low-magnetic versions of 304 stainless steel, and we can support magnetic permeability testing upon request.
You can use a simple handheld magnet to check the material:
If the magnet is weakly attracted or only sticks in certain areas, the steel is partially magnetic, likely due to cold working.
If there is no attraction, it is non-magnetic and fully austenitic.
Strong attraction indicates it may be a different grade (such as 430) or significantly cold-worked.
For more precise measurement, professional tools like permeability meters or Gaussmeters are used.
So, is 304 stainless steel magnetic? In its original, annealed form—no. But with mechanical processing or forming, yes, it can become slightly magnetic due to phase transformation.
This magnetic behavior does not reduce its corrosion resistance or suitability for most applications. For critical uses, always consult with your material supplier or request certified testing.
sakysteel is a trusted supplier of high-quality 304 stainless steel products, including wire, sheets, tubes, and bars. With full traceability, mill test certificates, and magnetic property control options, sakysteel ensures that you receive materials that meet both technical and performance standards.