Most ball bearings are magnetic but there are options where magnetic bearings are not acceptable. Chrome steel and most stainless steel bearings are magnetic. This will surprise many people in the case of stainless steel but the 440 grade steel used for most stainless steel bearings is very magnetic.
Many people believe that you can check to see if a bearing is stainless steel by holding a magnet to it but this doesn’t work most of the time. 440 grade stainless steel is a martensitic steel, almost as hard as chrome steel and definitely magnetic. The slightly magnetic steel bearings are made from the much softer 316 stainless steel which is an austenitic steel. Even 316 stainless steel can become more magnetic after cold working. 316 stainless steel bearings are only suitable for low loads and speeds.
Other non-magnetic bearing options are plastic bearings and full ceramic bearings. Our standard plastic bearings have glass balls or 316 stainless steel balls, both of which are non-magnetic. Plastic bearings, like 316 stainless steel bearings, are semi-precision and are designed for very low loads and speeds. Zirconia and Silicon Nitride full ceramic bearings are non-magnetic but will support much higher loads and speeds than 316 stainless steel and plastic bearings.
Contact us on +44 (0) 1993 842 555 or sales@smbbearings.com.