This term is often used to classify corrosion resistant materials. It is not a material parameter.
The corrosion resistance enables a classification of materials into groups which, under certain environmental conditions, can permanently ensure the corrosion resistance without additional measures.
Explanation: For clarification, reference is made to the definition of corrosion resistance classes in the General Building Inspectorate Approval Z-30.3-6 of 20 April/2009, Products, fasteners and components made of stainless steels. The concrete specification of a resistance class is absolutely necessary in tender and planning documents. If a steel is not classified, the responsible testing institutes can assign it to the resistance class system by means of tests or measurements.
In some cases, the term is also used for non-corrosion-resistant materials if the corrosion rate of materials can be reduced by certain measures (e.g. alloying additions). In this case, one often speaks of an increase in corrosion resistance without a corrosion resistant material being present.