In Peak Fasten Tech production process, many customers have queried about why stainless steel rusts, why stainless steel is also magnetic, and did you use fake materials for us? So we wrote this article as a technique know how to help our partners to learn more about the characteristics of stainless steel.
Why is stainless steel also magnetic? Most people use magnets to verify the stainless steel. Magnetic then it is stainless steel, not then means the material is fake. This is a one-sided misconception about the lack of understanding of stainless steel.
There are many kinds of stainless steel, which can be divided into several categories according to the preparation structure at room temperature:
  1. Austenitic type: such as 304, 321, 316, 310, etc.; (kitchenware, steel pipes, etc.)
  2. Martensite or ferrite type: such as 430, 420, 410, etc.;
Generally speaking, austenitic stainless steel and austenitic precipitation hardening stainless steel are non-magnetic (magnets cannot hold them), while other stainless steels have ferrite and are ferromagnetic (magnets can hold them). 
However, stainless steel cannot be judged by the presence or absence of magnetism alone. For stainless steel, regardless of whether the magnet can attract it or not, as long as it meets its quality standards, it is stainless steel.
Peak Fasten Tech, a professional one stop solution provider for specially fasteners. 
We are serving over 20 fastener dealers worldwide involved in industries like Aerospace, Automotive, Electronics, Construction, Industrial Storage, Home Garden etc. 
And we can be a good choice for your supply chain as well regarding specialty bolts & nuts, Stamping and CNC machining. 

Knowledge extension:
The austenitic type is non-magnetic or weakly magnetic, while the martensite or ferrite is magnetic. Most of the stainless steels usually used as decorative tube sheets are austenitic 304 materials, which are generally non-magnetic or weakly magnetic. However, magnetism may also occur due to chemical composition fluctuations or different processing states caused by smelting.
As mentioned above, austenite is non-magnetic or weakly magnetic, while martensite or ferrite is magnetic. Due to component segregation or improper heat treatment during smelting, a small amount of martensite or ferrite in austenitic 304 stainless steel will be caused. In this way, 304 stainless steel will have weak magnetism.
In addition, after cold working of 304 stainless steel, the preparatory structure will also be transformed into martensite. The greater the cold working deformation, the more martensite transformation, and the greater the magnetic properties of the steel. In order to completely eliminate the magnetic properties of 304 steel caused by the above reasons, the stable austenite preparation can be restored by high-temperature solution treatment, thereby eliminating the magnetic properties.
In particular, the magnetism of 304 stainless steel caused by the above reasons is completely different from the magnetism of other materials such as 430 and carbon steel, that is to say, the magnetism of 304 steel always shows weak magnetism.
This tells us that if the stainless steel strip is weakly magnetic or completely non-magnetic, it should be judged as 304 or 316 material; if it is the same as carbon steel, it shows strong magnetism, then must not 304 material.
Of course, if chromium and higher nickel are added to molten steel, the resulting austenitic steel is stainless steel that cannot be attracted by magnets. If the main alloying elements in molten steel are chromium, iron, carbon and a small amount of nickel (or no nickel), the resulting steel is stainless steel that can be attracted by magnets, also called ferritic stainless steel or martensitic stainless steel. In addition to austenitic stainless steel magnets that cannot be attracted, ferritic and martensitic stainless steels are magnetic. Since nickel is scarce in the world, the price is relatively high. Therefore, the stainless steel with high nickel content is also more expensive in the market, and the magnet cannot attract it. At present, the proportion of austenitic stainless steel in stainless steel is still very large, so people have the misconception that all stainless steels are non-magnetic.
In fact, there is also a stainless steel magnet that cannot be attracted, that is, stainless steel with high manganese or nitrogen content and low nickel or no nickel, that is, chromium-manganese austenitic stainless steel. Therefore, it cannot be judged whether it is stainless steel based on whether it is magnetic or not.
Peak Fasten Tech, a professional one stop solution provider for specially fasteners. 
We are serving over 20 fastener dealers worldwide involved in industries like Aerospace, Automotive, Electronics, Construction, Industrial Storage, Home Garden etc. 

And we can be a good choice for your supply chain as well regarding specialty bolts & nuts, Stamping and CNC machining.