S275, S355, A36, SS400. The same beam can arrive under four different grade names depending on which standard the mill rolled it to, and UAE projects specify all of them. This page explains what each one means, how they compare, and which one to ask for.
What the grade name tells you
For European grades the number is the minimum yield strength in N/mm² (MPa) for thinner material. S275 yields at 275 MPa, S355 at 355 MPa. The S simply means structural steel. The letters after it, JR, J0 or J2, tell you the temperature the steel was impact tested at.
American and Japanese grades name things differently. ASTM A36 is named after its 36 ksi yield, which is about 250 MPa. JIS SS400 is named after its minimum tensile strength of 400 MPa, not its yield.
Side by side
| Grade | Standard | Min yield (thin material) | Tensile strength |
|---|---|---|---|
| S235JR | EN 10025-2 | 235 MPa | 360 to 510 MPa |
| ASTM A36 | ASTM A36 | 250 MPa | 400 to 550 MPa |
| SS400 | JIS G3101 | 245 MPa | 400 to 510 MPa |
| S275JR | EN 10025-2 | 275 MPa | 410 to 560 MPa |
| ASTM A572 Gr 50 | ASTM A572 | 345 MPa | 450 MPa min |
| S355JR | EN 10025-2 | 355 MPa | 470 to 630 MPa |
Yield figures are for material up to 16 mm thick. EN grades step down as thickness goes up: S355 falls to 345 MPa between 16 and 40 mm, and S275 falls to 265 MPa. If your design depends on the yield figure, check the thickness band, not just the grade name.
JR, J0 and J2
These suffixes are about toughness, not strength. Each one guarantees at least 27 joules of impact energy in a Charpy test at a set temperature.
| Suffix | Impact test temperature |
|---|---|
| JR | +20 °C |
| J0 | 0 °C |
| J2 | −20 °C |
In the UAE climate JR is fine for most building work. J0 or J2 tend to appear on bridges, cranes, offshore and oil and gas specifications, where the concern is fatigue and dynamic loading rather than cold weather. If a consultant has written J2, do not substitute JR to save money. It will fail inspection.
Are they interchangeable?
Roughly, in groups, and only with the engineer's agreement.
- A36, SS400 and S235 or S275 sit in the same general band. A36 and SS400 are commonly accepted in place of each other on general fabrication. S275 is slightly stronger than both.
- S355 and A572 Grade 50 are the higher strength pair and are often treated as equivalent.
- Going up is usually safe, going down never is. Supplying S355 where S275 was specified rarely causes a problem. Supplying S275 against an S355 specification is a design failure waiting to happen.
Equivalence is a judgement for the designer, not the supplier. If your drawing says one grade and the market has another, get the substitution approved in writing before the steel is cut.
Which grade to ask for
- Gates, railings, sheds, general fabrication: A36, SS400 or S275. Whatever is readily available in the section you need.
- Building frames and warehouses: usually S275 or S355, as specified on the structural drawings.
- Heavy structures, long spans, cranes, energy sector: S355 with the impact grade the specification calls for.
Proving the grade: the mill test certificate
A grade name on a delivery note proves nothing. The mill test certificate does. It records the heat number, the chemical analysis and the tested mechanical properties of the actual material. Most consultants in the UAE expect an EN 10204 type 3.1 certificate, which is issued by the mill and signed off by its own inspection department independently of production.
When the steel arrives, check that the heat number stamped or stencilled on the material matches the certificate. A certificate that does not trace to the steel in front of you is paper, not proof.
Frequently asked questions
Is SS400 the same as A36?
Very close, and widely accepted as equivalent for general work. They come from different standards with slightly different limits, so on a controlled project confirm with the engineer.
Can S355 replace S275?
Structurally it is stronger, so it is usually acceptable, but weld procedures can differ. Get it approved rather than assumed.
Do you supply mill test certificates?
Yes, MTCs are issued with the material.
Getting a price
Send your list with the grade and standard through the steel quote request form or on WhatsApp at +971 56 227 5722. If you are not sure which grade you need, send the drawing reference and we will tell you what the specification actually requires. Need the weights too? See the steel weight chart.