Are bearings made of stainless steel 100 per cent corrosion-resistant?

The difference between unalloyed steel and rust-free stainless steel is the percentage of chrome of at least 10.5 % which is included in stainless steel. Due to the percentage of chrome, a thin layer will be formed by contact with oxygen on the surface of the steel. This layer is called passive layer, which protects the base material against corrosion. If the passive layer is however damaged by external influences, corrosion will develop. Contrary to the general opinion, stainless steel is 100 per cent rust-resistant, a process of rusting is according to this explanation very well possible.

Some factors accelerate the development of corrosion on bearings made of stainless steel:

  • the contact with rust film can lead to a damage of the passive layer
  • an oxygen- poor or an oxygen-free environment: Here, the passive layer can form itself again and guarantee the corrosion protection. When choosing the material, it is absolutely necessary to consider in which environment the use will take place.
  • wrong bearing handling: It is absolutely necessary to avoid the cleaning with aggressive acids or steel wool.

Tip: Also bearings made of stainless steel require maintenance and if necessary softly superficial cleaning with a rag to avoid corrosion.