Material number 1.0038: S235JR
1.0038 is the European material number (Werkstoffnummer, EN 10027-2) for S235JR, non-alloy hot-rolled structural steel specified in EN 10025-2.
What 1.0038 means
EN 10027-2 material numbers have the form 1.XXYY: the leading 1 is steel; the next two digits give the steel group (00 → base steels); 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 1.0038 has stayed constant while the symbolic name moved from St37-2 to S235JR.
S235JR at a glance
S235JR is the entry grade of EN 10025-2, the European standard for hot-rolled non-alloy structural steels. The designation encodes everything a buyer needs: S = structural, 235 = minimum yield strength in MPa for thicknesses up to 16 mm, J = 27 J Charpy energy, R = tested at room temperature (+20 °C). Its Werkstoff number is 1.0038.
It is a low-carbon (≤ 0.17 %) steel supplied as-rolled (+AR) or normalized/normalizing-rolled (+N). Because the carbon equivalent is capped at 0.35 %, it welds without preheat in all common thicknesses, which is why S235JR is the default material for secondary steelwork, general fabrication, light frames and any part where stiffness rather than strength governs the design.
S235JR replaced DIN St37-2 and BS 4360 40B in 1994; the old names survive on legacy drawings, so this page lists them alongside the ASTM, JIS, GB and GOST cross-references.
Full data sheet for S235JR → · Equivalent grades →