Steel Tube Handbook - 2018

105 Designation of steels for construction and general use S – structural steel 235 – minimum yield strength in N/mm 2 Signs at the end of steel designation – additional symbols for steel names • non-alloy steel J – impact test, min. average absorbed energy KV – 27J R – room temperature 0 – temperature 0°C 2 – temperature -20°C H – hollow section • fine grain steel (ferritic grain size equal to or finer than 6) basic series N – normalized structure H – hollow section low temperature series N – normalized structure L – low temperature series H – hollow section Fine grain structural steel designation according to DIN 17124 StE – basic series (–20 °C) TStE – deep-drawing series with minimum absorbed energy at temperature of –50 °C EStE – deep-drawing series with minimum absorbed energy at temperature of –60 °C 255 – minimum yield strength in N/mm 2 Designation of steels for machine parts • steel for tubes for mechanical treatment: steel E355 + AR, E 355 + N E – steel for machine par ts, 355 – minimum yield strength in N/mm2, +AR – heat treatment is not required, +N – normalising annealed or formed steel 20MnV6 steel designated by chemical composition – guaranteed mean C content 0,20%, guaranteed content Mn and V +AR – heat teratment is not required, +N – normalising annealed or formed • steel for machine parts: steel without heat treatment after mechanical treatment non-alloy steel E 235, E275, E315, E355 Condition +AR or +N steel with specific impact qualities (fine-grain) E275K2, E355K2 K2 – guaranteed characteristic of impact energy 40 J (K) by temperature –20 °C steel with heat treatment after mechanical treatment steel C22E C – steel with carbon content 0,22%, E – reference to maximum checked content of S and P steel 38Mn6 – guaranteed mean C content and guaranteed Mn content Steel designation according to EN