Definition
EN 10025 is the European harmonised standard for hot-rolled structural steel products. It is published in six parts, each covering a family of structural steel: non-alloy, normalised, thermomechanically rolled, weathering, and high-strength quenched and tempered. Together the six parts define the grades, sub-grades, chemistry envelopes, mechanical properties, delivery conditions and marking requirements for the structural steel that dominates European and GCC construction.
The six parts
EN 10025-1: General technical delivery conditions. Defines testing, marking, certification and surface quality common to all parts. EN 10025-2: Non-alloy structural steels. Grades S235, S275, S355, S450. The GCC workhorse. EN 10025-3: Normalised / normalised-rolled weldable fine grain. Grades S275N, S355N, S420N, S460N. Used where fine grain and consistent toughness are needed. EN 10025-4: Thermomechanically rolled (TMCP) weldable fine grain. Grades S275M, S355M, S420M, S460M. Higher strength with lower carbon for excellent weldability. EN 10025-5: Weathering steels. Grades S235J0W, S355J0W, S355J2W. Forms a stable rust layer in atmospheric service. EN 10025-6: Flat products of high-yield-strength quenched and tempered steels. Grades S460QL, S690QL, S960QL. Used for crane structures, mining equipment and offshore.
Sub-grade letter codes
JR, Charpy impact 27J at +20°C. J0, Charpy impact 27J at 0°C. J2, Charpy impact 27J at -20°C. K2, Charpy impact 40J at -20°C. N, Normalised or normalised-rolled. M, Thermomechanically rolled. W, Weathering steel. QL, Quenched and tempered, low temperature (-40°C). QL1, Quenched and tempered, low temperature (-60°C).
A full grade designation like S355 J2 +N reads as: structural steel, 355 MPa minimum yield, 27J impact at -20°C, supplied in the normalised condition.
Mechanical properties by grade
Grade | Min yield (≤16mm) | Tensile range | Min elongation S235 | 235 MPa | 360-510 MPa | 26% S275 | 275 MPa | 410-560 MPa | 23% S355 | 355 MPa | 470-630 MPa | 22% S450 | 440 MPa | 550-720 MPa | 17% S460N | 460 MPa | 540-720 MPa | 17% S690QL | 690 MPa | 770-940 MPa | 14%
Yield drops with increasing thickness in steps defined in each part of the standard.
Delivery conditions
+AR, As rolled. +N, Normalised. +NL, Normalised, low temperature impact. +M, Thermomechanically rolled. +ML, Thermomechanically rolled, low temperature. +Q, Quenched. +QT, Quenched and tempered.
The delivery condition determines microstructure and the resulting balance of strength, toughness and weldability.
Certification: EN 10204
EN 10025 cross-references EN 10204 for certification. The most-used certification classes are: 2.1, Declaration of compliance (rarely accepted on structural work). 2.2, Test report with non-specific results. 3.1, Mill-issued inspection certificate with specific results, signed by mill QA. 3.2, Inspection certificate witnessed by an independent third party.
GCC infrastructure and EPC tenders typically require EN 10204 3.1 minimum, with 3.2 for bridges, lifting structures and critical infrastructure.
How EN 10025 appears on GCC purchase orders
"Structural steel sections to EN 10025-2 S355 J2+N, MTC to EN 10204 3.1, ultrasonic testing to EN 10160 where applicable", this is the standard procurement clause used by Emirati and Saudi contractors on most modern frame and bridge tenders.
Where weathering steel is specified for architectural facades: "EN 10025-5 S355 J2W". Where HSLA fine-grain plate is specified for offshore or crane structures: "EN 10025-6 S690QL".
Relationship to ASTM and BS
S275 ≈ ASTM A36 / BS 4360 Grade 43. S355 ≈ ASTM A572 Gr 50 / ASTM A992 / BS 4360 Grade 50. S235JR ≈ no exact ASTM equivalent; A36 is the nearest. S355J2W ≈ ASTM A588. S690QL ≈ ASTM A514.
Dual-certified MTCs (EN + ASTM on one heat) are routinely issued by major mills supplying the GCC.