EN10025-2 S275JR is a widely used non-alloy (carbon) structural steel plate, classified under the European standard EN 10025-2. It is not a low-alloy high-strength steel (HSLA). Here is a technical clarification and product breakdown.
Correct Classification: Non-Alloy Structural Steel
Conclusion: S275JR is a standard carbon structural steel, not a high-strength low-alloy (HSLA) steel. HSLA steels start roughly at grade S355 and above, and are covered by different parts of EN 10025 (Parts 4, 5, and 6).
EN10025-2 S275JR Carbon and Low-alloy High-strength Steel Plate Chemical Composition and Mechanical Property
| Standard | EN 10025-2 (Non-alloy structural steels) | EN 10025-4 (Thermomechanical rolled weldable fine grain) or EN 10025-6 (Quenched & tempered) |
| Alloying | Carbon-Manganese Steel. No intentional alloying with Cr, Ni, Mo, etc., beyond residual levels. | Micro-alloyed with Nb, V, Ti, and may contain Cu, Ni, Cr, Mo for specific properties. |
| Primary Strengthening Mechanism | Solid solution strengthening (Mn), grain refinement (Al for fine grain). | Grain refinement, precipitation hardening, and for Q&T grades, transformation hardening. |
| Typical Min. Yield | 275 MPa (for t ≤ 16 mm) | ≥ 355 MPa to ≥ 960 MPa |
| Key Feature | Good weldability & formability, low cost. | High strength-to-weight ratio, good toughness at low temperatures. |
| Delivery Condition | As-rolled (AR), Normalized (N). | Thermomechanically rolled (M) or Quenched & Tempered (Q). |
Grade | Chemical composition % MAX | |||||||
THICKNESS(MM) | C | Mn | Si | P | S | N | Cu | |
S275JR | ≦40 | 0.21 | 1.5 | ~ | 0.035 | 0.035 | 0.012 | 0.55 |
>40 | 0.22 | |||||||
| Mechanical properties MIN | |||||||
| Yield Strength | Tensile Strength | Elongation in 2 in. | |||||
≦16 | 275 | 410-580 | 15 | |||||
Key Takeaway
EN10025-2 S275JR is a standard, non-alloy (carbon steel) structural plate with moderate strength and guaranteed room-temperature toughness. It is a fundamental, economical choice for a vast range of construction and engineering applications but belongs to a different category (and standard part) than true low-alloy high-strength steels like S355ML, S460NL, or S690QL.
