Before classifying steel, the standard establishes what actually constitutes "steel." According to EN 10020, steel is a material in which iron (Fe) is the predominant element, and the carbon (C) content is generally less than 2% by weight.
An EN 10020 PDF details two distinct methods for classifying steel grades: en 10020 pdf
The document functions primarily to divide steel into classes based on two criteria: Before classifying steel
: These are the cleanest non-alloy steels. They have very low amounts of phosphorus and sulfur. They react very well to heat treatments. Quality Classes for Alloy Steels en 10020 pdf