Do you use your refrigerator as a message board or rotating photo display? If so, when you're shopping for new appliances, you need to know whether your magnet collection will stick to stainless steel. The short answer is maybe.
It depends on the composition of the stainless steel, how thick the stainless steel is, the material beneath the stainless steel, and how strong the magnet is.
What Is a Magnet?
Remember playing with magnets during elementary science class? A magnetic material, such as iron (Fe), is surrounded by an invisible force field with a north and south pole. The opposite poles have a field of attraction that draws like elements together.
Metals with a permanent magnetic attraction are labeled ferromagnetic, referring to the Latin term ferro, which means iron.
What Is Stainless Steel?
Stainless steel is a metal created by alloying iron with one or more elements. In general, there are two types of stainless steels based on their physical properties:
- Ferritic is generally ferromagnetic due to its high concentration of iron, which is combined with chromium, molybdenum, and silicon. Also, its fundamental atomic structure creates magnetization.
- Austenitic is usually not magnetic, because the iron is alloyed with nickel, manganese, carbon, and nitrogen.
Thomas Devine, a materials science and engineering professor at the University of California, Berkely explains the difference between these two types of stainless steel in greater depth. "Fundamentally, the reasons why ferritic stainless steels are ferromagnetic while austenitic stainless steels are not are quantum-mechanical in nature."
The most popular stainless steel has good forming properties, resists corrosion, and is strong. However, it is not magnetic because it is alloyed with nickel, manganese, carbon, and nitrogen (austenitic).
Why Do Magnets Stick to Some Stainless Steel Appliances?
If the stainless steel skin of an appliance is relatively thin and the underlying core is ferromagnetic, a strong magnet will cling to the surface because the magnetic force penetrates through the stainless steel to the underlying material.
So the best way to determine whether a magnet will stick or not is to try it before you buy it.
Surprisingly, a magnet may stick to the side of a refrigerator but not the door. Or it will cling to a dishwasher but not the refrigerator. Again, it's most likely due to the underlying materials.