Why is Stainless Steel Magnetic?

People often think that magnets can be used to absorb stainless steel materials to verify their quality and authenticity. If they are not attractive and non-magnetic,  are considered to be good, and  genuine; if they are magnetic, they are considered to be counterfeit products. In fact, this is an extremely indentifying error , and it is one-sided and impractical method .

Iron and steel are distinguished by their carbon content. Iron-carbon alloys with a carbon content of less than 2% are steel, and those with a carbon content of more than 2% are called iron. Steel is widely used because of its toughness, elasticity and rigidity. All you come into contact with in life are steel, but people call it differently. For stainless steel, no matter whether the magnet can be attracted or not, as long as it meets its quality standards, it is stainless steel.

 From a metallurgical point of view, there is no such thing as stainless iron. The main element of corrosion resistance of stainless steel is chromium. Steel with chromium content above 10.5% will not rust. The alloying elements added during smelting are different, and there is a difference between magnets that can attract and cannot attract. Nickel has very few reserves in the world, and the price is relatively expensive. Therefore, the price of stainless steel with high nickel content is also higher in the market, and the magnet is not attracted. In fact, there is another kind of stainless steel magnet that cannot be attracted. That is stainless steel with high manganese content and low nickel content or no nickel content.

There are many types of stainless steel, which can be divided into several categories according to the organizational structure at room temperature:Austenite is non-magnetic or weakly magnetic, and martensite or ferrite is magnetic.
     1. Austenite type: such as 304, 321, 316, 310, etc.;
     2. Martensite or ferrite type: such as 430, 420, 410, etc.;
    
In summary, a more professional method should be used to detect the material of stainless steel. (Spectral detection, stainless steel identification solution detection).