Q. Why does Metal Fabric (M/F) made of Stainless Steel exhibit magnetism?

Metal Fabrics (M/F) generally use Stainless Steel of the 300 series as the base material.

There are often questions raised about the product's magnetic properties based on the general understanding that stainless steel does not exhibit magnetism.

I will briefly address the magnetism of Metal Fabric (Stainless Steel) to help consumers understand.

1. Types of Stainless Steel

Stainless steel can be broadly categorized into austenitic (300 series, FCC), martensitic (BCC), and ferritic types. Among these, the austenitic 300 series (FCC) is typically known for being non-magnetic.

2. Cold Work-Induced Magnetism

However, it is important to note that even 300-series stainless steel can develop magnetism when subjected to cold processing, which causes microstructural changes.

Specifically, after cold working such as wire drawing (a process where a rod of a certain thickness is pulled to make thin strands, similar to stretching taffy), a phase transformation from the FCC structure to the BCC structure can occur, resulting in the material becoming magnetic depending on the processing conditions.

3. Degree of Magnetism

Furthermore, even 300-series stainless steel (FCC) is not completely non-magnetic, but exhibits varying degrees of magnetism.

This is referred to as Magnetic Permeability. Below is a brief summary of the magnetic permeability for standard stainless steel grades (304, 316):

1.0 : Does not move when a magnet is applied

1.1 : Slight movement when a magnet is applied

11.0 : Loosely responds to the magnet

4. Summary

In conclusion, even though the austenitic 300 series (FCC) is generally considered non-magnetic, it is not entirely free from magnetism.

For the metal fabric's primary materials—cables (rope) and wires (rod)—the cold processing steps such as drawing and twisting (like braiding threads) cause microscopic structural changes that lead to varying degrees of magnetism.

However, the material's properties are not fundamentally altered, and the intrinsic qualities of stainless steel remain intact.

There is no need to worry, as the material's composition and characteristics remain the same.

The most reliable way to verify this is by collecting samples and having them tested at an accredited chemical testing laboratory.