Structural steel - Wikipedia
https://en.wikipedia.org/wiki/Structural_steelMost steels used throughout Europe are specified to comply with the European standard EN 10025. However, many national standards also remain in force. Typical grades are described as 'S275J2' or 'S355K2W'. In these examples, 'S' denotes structural rather than engineering steel; 275 or 355 denotes the yield strength in newtons per square millimetre or the equivalent megapascals; J2 o…