S235JR vs S355JR: differences explained
S235JR vs S355JR: both tested at +20 °C, both the entry impact quality of their grade, 235 against 355 MPa yield — the comparison that matters when the section is already fixed and only the grade is in question.
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Overview
This is the S235 against S355 question asked inside one impact class. JR means the Charpy test is carried out at room temperature, 27 joules, on both grades — so the choice here is purely strength and chemistry, with the toughness question parked.
It comes up in two situations. The first is a supplier offering S355JR where a drawing calls for S235JR: structurally an upgrade, commercially usually free, but still a change. The second is the opposite, an offer of S235JR against an S355 drawing, which is a downgrade and has to be refused unless the designer re-checks. Both cases hinge on the same table.
S235JR vs S355JR side by side
| Property | S235JR | S355JR |
|---|---|---|
| Standard | EN 10025-2:2019 | EN 10025-2:2019 |
| Material number | 1.0038 | 1.0045 |
| Impact test | 27 J at +20 °C | 27 J at +20 °C |
| Old names | St37-2, Fe360B, 40B | St52-3, Fe510B, 50B |
| Min. yield ReH, ≤ 16 mm | 235 MPa (34 ksi) | 355 MPa (51 ksi) |
| Min. yield, 16–40 mm | 225 MPa | 345 MPa |
| Min. yield, 40–63 mm | 215 MPa | 335 MPa |
| Tensile Rm, 3–100 mm | 360–510 MPa | 470–630 MPa |
| Elongation A, ≥ 3 mm | 26 % | 22 % |
| Max C, ≤ 30 mm | 0.17 % | 0.24 % |
| Max Mn | 1.40 % | 1.60 % |
| Max Si | not specified | 0.55 % |
| Carbon equivalent CEV, ≤ 30 mm | 0.35 % | 0.45 % |
| Cold forming | Excellent — the lower carbon tolerates tight radii | Good, but larger bend radii and more springback |
| Weldability | Excellent in all thicknesses | Excellent to ~30 mm; check CEV above that |
| Common forms | Sections, hollow sections, sheet, bar, plate | Sections, hollow sections, plate, heavy plate |
| Where it dominates | General fabrication, frames, handrails, brackets | Load-bearing frames, machine bases, cranes |
| ASTM closest | A283 Gr C / A36 (with caveats) | A572 Gr 50 |
| JIS closest | SS400 / SM400A | SM490A |
| GB closest | Q235B | Q345B |
Which should you choose?
S355JR for anything structural, because the 51 per cent yield advantage translates directly into smaller sections and the price gap is small. S235JR where forming, not strength, is the job — brackets, trims, cold-bent parts and anything drawn or pressed, where the lower carbon and the 26 per cent elongation make the steel behave. Accepting S355JR against an S235JR drawing is normally safe; the reverse never is without a design check.
- Cold forming, pressing and tight bend radii — 26 % elongation against 22 %
- Thin sheet and light fabrication where strength is not the limit
- Welding thick sections without preheat: CEV is capped at 0.35 %
- Machining-heavy parts, where the softer steel is kinder to tooling
- Galvanizing: the lower silicon range gives a more predictable coating appearance
- Beams, columns and any member sized on bending or axial capacity
- Plate and machine frames, where a thinner plate at the same capacity saves real money
- Crane runways, trailers, lifting frames and equipment skids
- Anywhere the structure is already detailed in S355 and mixing grades would confuse fabrication
- Export work where S355 is the assumed default grade
Frequently asked questions
Is S355JR stronger than S235JR?
Yes — 355 MPa minimum yield against 235 MPa up to 16 mm, and 470–630 MPa tensile against 360–510. Stiffness is identical: both have a 210 GPa modulus, so deflection does not improve.
Can the supplier send S355JR instead of S235JR?
Usually acceptable, since every mechanical property is higher, but it is a substitution the designer should confirm. Cold-formed parts are the exception: S355 springs back more and needs larger radii.
What does JR mean?
The impact quality: a Charpy V-notch test of 27 joules at +20 °C. J0 is the same energy at 0 °C, J2 at −20 °C. JR is the entry class and is not suitable for low-temperature service.
Which galvanizes better?
S235JR, marginally. Coating appearance is driven by silicon and phosphorus; S355 permits up to 0.55 % silicon, which can push the coating into the Sandelin range and give a dull, thicker layer. Ask for the silicon content before galvanizing critical visible work.
Do they cost the same?
Close. In Europe S355JR is usually within a few per cent of S235JR and sometimes identical, because mills roll more of it. In markets where S235 dominates stock, the order flips.
Which one is St37 and which is St52?
S235JR replaced St37-2 and S355JR replaced St52-3 when DIN 17100 was withdrawn. The old names are still used commercially in Türkiye, Germany and much of the Balkans.
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Verified against EN 10025-2:2019. Last checked: September 2026.