EN 10020 defines stainless as ≥10.5% Cr. It does not guarantee corrosion resistance in all environments. This is a common point of legal confusion.
Steels that are not stainless but contain at least one element at or above the threshold limits defined in the standard's "Table 1". 2. Main Quality Classes en 10020 pdf
Characterized by higher purity and stricter control of chemical composition, often intended for quenching and tempering. EN 10020 defines stainless as ≥10