Material number 1.0577: S355J2
1.0577 is the European material number (Werkstoffnummer, EN 10027-2) for S355J2, non-alloy hot-rolled structural steel, −20 °C impact specified in EN 10025-2.
What 1.0577 means
EN 10027-2 material numbers have the form 1.XXYY: the leading 1 is steel; the next two digits give the steel group (05 → steels 0.25–0.55 % C or Rm 500–700 MPa); the last two digits are a sequential number within that group. The number is unique to one composition and survives name changes, which is why 1.0577 has stayed constant while the symbolic name moved from St52-3 N to S355J2.
S355J2 at a glance
S355J2 is the plate grade engineers actually specify when they write "S355": 355 MPa minimum yield, 470–630 MPa tensile and a Charpy guarantee of 27 J at −20 °C, Werkstoff number 1.0577. The J2 suffix also brings tighter cleanliness (P, S ≤ 0.025 %) and mandatory full killing, so the steel is more uniform than S355JR from the same mill.
Most S355J2 plate is delivered normalized or normalizing-rolled (+N), giving a fine ferrite–pearlite structure that keeps toughness in thicknesses up to 250 mm. Crane makers, bridge fabricators and machinery builders standardize on it because it covers most temperate-climate service without moving to the fine-grain S355N/NL family of EN 10025-3.
Old drawings call it St52-3 N or Fe510D; in the United States ASTM A572 Grade 50 with Charpy supplement (or A709-50 for bridges) is the practical equivalent, and in China Q355D.
Full data sheet for S355J2 → · Equivalent grades →