30 9 月, 2026
EN 10025 S235JR, S275JR and S355JR Explained
The EN 10025-2 grade name is read in three parts: S for structural steel, the number for the minimum yield strength in MPa at the reference thickness, and the trailing letters for the impact toughness class. So S235JR is a 235 MPa structural steel with a JR toughness class, S275JR is 275 MPa, and S355JR is 355 MPa.
Reading the name
| Part | Meaning |
|---|---|
| S | Structural steel |
| 235 / 275 / 355 | Minimum yield strength in MPa at the reference thickness |
| J | Impact energy class of 27 J |
| R | Impact test temperature of +20 °C |
| H | Hollow section (when it appears, e.g. S355J2H) |
How the grades map to Chinese and other systems
| Chinese grade | ASTM | EN | JIS |
|---|---|---|---|
| Q235B GB/T 700 |
A36 / A283 Gr.C | S235JR (EN 10025-2) | SS400 (JIS G3101) |
| Q355B GB/T 1591 |
A572 Gr.50 / A992 | S355JR (EN 10025-2) | SM490 (JIS G3106) |
| SS400 (JIS) JIS G3101 |
A36 | S235JR | SS400 |
| Q195 GB/T 700 |
A36 (approx.) | S185 (EN 10025-2) | SS330 (JIS G3101) |
Our grade database maps the Chinese grades to their nearest ASTM, EN and JIS equivalents. The table is a shortlist tool; the certificate must always name the standard the project specifies.
What to specify
- The full EN designation, including the toughness class letters
- The product form and dimensions, and the tolerance standard
- The certification required, such as EN 10204 3.1
- The delivery condition if the steel is to be normalised or thermomechanically rolled
Related reading
Frequently asked questions
What does S355JR mean?
S355JR is a structural steel to EN 10025-2 with a minimum yield strength of 355 MPa and a JR toughness class, meaning 27 J impact energy verified at +20 C.
What is the difference between S235JR and S275JR?
The number is the minimum yield strength. S275JR is a 275 MPa grade and S235JR is a 235 MPa grade; both carry the same JR toughness class at +20 C.
What does the JR suffix mean?
J is the impact energy class, 27 J, and R is the impact test temperature, +20 C. A J0 grade would be tested at 0 C and a J2 grade at -20 C.
Tell us the standard, grade, form and size you need and we will quote against it. See our steel product catalogue, how we inspect and certify each order, or request a quotation.