EN 10025 S235JR vs S275JR vs S355JR Carbon Steel Comparison

EN 10025-2 is the most widely specified European standard for hot-rolled non-alloy structural steel. Within the standard, the S235, S275, and S355 grades define three strength tiers – each available with impact grades (JR, J0, J2) that qualify the steel for different service temperatures. For buyers outside Europe who cross-reference EN grades with ASTM A36, JIS, or GB equivalents, the three-tier naming convention can cause confusion and mis-procurement. Selecting the right S-grade affects strength, weight, cost, weldability, and ultimately the safety of your structure.

This guide compares S235JR, S275JR, and S355JR side by side on chemistry, mechanical properties, weldability, and price. It then explains when each tier is the right specification for your project and how to avoid common cross-reference errors.

1. The EN 10025-2 Naming System

EN 10025-2 designations encode three pieces of information:

S – Structural steel (vs P for pressure vessel, E for engineering).
Number (235, 275, 355) – Minimum yield strength in MPa for thickness up to 16 mm.
Impact grade suffix – JR (Charpy tested at +20°C, 27 J minimum), J0 (tested at 0°C), J2 (tested at -20°C).

So S235JR is structural steel with 235 MPa minimum yield (up to 16 mm) and Charpy tested at +20°C. S355J2 is 355 MPa yield tested at -20°C. The impact suffix is independent of the strength tier.

2. Standards and Scope

EN 10025-2:2019 – Hot rolled products of structural steels – Part 2: Technical delivery conditions for non-alloy structural steels. This is the source for S235, S275, S355 (including JR, J0, J2 subgrades) in plate, wide flat, sections, bars, and sheet piling.
EN 10025-1 – General technical delivery requirements (common to all parts of EN 10025).
EN 10029 – Tolerances for plate thickness.
EN 10034 – Tolerances for I and H sections.
EN 10056 – Tolerances for equal and unequal angles.
EN 10204 – Inspection document types (3.1 by default, 3.2 optional).

3. Chemical Composition Comparison

The chemistry envelope is comparable across the three grades, with manganese and carbon scaling up for the higher yield levels:

Element	S235JR max %	S275JR max %	S355JR max %
C (max, product analysis)	0.21 (for up to 40 mm)	0.23 (for up to 40 mm)	0.24 (for up to 40 mm)
Si (max)	1.60	1.60	0.55
Mn (max)	1.60	1.60	1.60
P (max)	0.030	0.030	0.030
S (max)	0.030	0.030	0.030
N (max)	0.009 (unless agreed)	0.009	0.009
Cu (max residual)	0.40 (unless CrCu Ni alloyed)	0.40	0.40
CEV (max, up to 40 mm)	0.35	0.40	0.45
Micro-alloying	Not specified	Not specified	Not specified (still a non-alloy steel)

Note: S355JR is a non-alloy steel in EN 10025-2. The higher strength comes from higher carbon and manganese, not microalloying. S355 is more difficult to weld than S235 but well within the practical range with low-hydrogen electrodes.

4. Mechanical Properties – Yield Strength by Thickness

Yield strength decreases with thickness. This is the most critical difference between the three grades for designers:

Thickness	S235JR Yield min (MPa)	S275JR Yield min (MPa)	S355JR Yield min (MPa)
Up to 16 mm	235	275	355
16 to 40 mm	225	265	345
40 to 63 mm	215	255	335
63 to 80 mm	195	245	325
80 to 100 mm	185	235	315
100 to 150 mm	175	225	295
150 to 200 mm	165	215	285

The yield gap between grades widens with thickness. For 150-200 mm plate, S355JR offers 70 MPa advantage over S275JR and 120 MPa over S235JR.

5. Mechanical Properties – Tensile and Elongation

Property	S235JR	S275JR	S355JR
Tensile Rm (MPa, up to 100 mm)	360-510	410-560	470-630
Minimum elongation A5 (%)	26	23	22
Minimum elongation A50mm (%) (typical, for strip)	24	21	20
Impact energy KV8 at +20°C (J min, longitudinal)	27	27	27
Hardness Brinell (typical)	110-150	120-160	135-185

Both tensile and impact values are similar; the dominant difference is the yield tier. Higher yield means a smaller or thinner section can carry the same load, which is the design case for upgrading from S235 to S355.

6. Impact Grade Comparison (JR vs J0 vs J2)

The three strength tiers are each available with three impact grades, giving nine total designations per delivery condition:

Grade	Test Temperature	Min Energy (J longitudinal)	Min Energy (J transverse)
JR	+20°C	27	20
J0	0°C	27	20
J2	-20°C	27	20
J2G3 (now obsolete, see EN 10025-2:2019)	-20°C with normalized delivery	27	20

For low-temperature service below -20°C, EN 10025-3 (normalized fine-grain grades) or EN 10025-4 (thermomechanical fine-grain grades) are required (e.g., S355NL or S355ML).

7. Weldability and CEV

Property	S235JR	S275JR	S355JR
CEV max (up to 40 mm)	0.35	0.40	0.45
CEV max (40-63 mm)	0.38	0.42	0.47
Preheat for thin section under 20 mm	Generally not required above 5°C ambient	Generally not required above 5°C ambient	Generally not required above 5°C ambient
Preheat for thick section above 50 mm	50-100°C recommended	50-100°C recommended	100°C recommended (higher CEV)
Low-hydrogen electrodes	E7018 for thick sections	E7018 for thick sections	E7018 mandatory for thick sections
Welding consumable matching strength	G42XX (e.g., ER70S-6, E7018)	G42XX	G42XX or G46XX (e.g., ER80S-D2 if matching higher strength)

S235 and S275 are straightforward to weld. S355 is readily weldable with low-hydrogen practice and appropriate preheat for thicker sections. The EN 1011-2 welding recommendations provide preheat tables based on CEV, thickness, and hydrogen content.

8. Cross-Reference to Other Standards

EN 10025-2	ASTM (approximate)	JIS	GB/T	Notes
S235JR	A36 (with caveats)	SS400 (similar tensile, slightly lower yield)	Q235B (similar but impact test format differs)	Closest ASTM equivalent is A36 (250 MPa yield).
S275JR	–	SM400A/B	Q275 (rarely produced)	Less common in ASTM; consider A529 Grade 55.
S355JR	A572 Grade 50 (closest)	SM490A/B/YB	Q345B (close; Q355 per revised GB/T 1591)	A572 Grade 50 is the most-used cross-reference; Q345B is the standard Chinese equivalent.

Cross-reference is approximate. Each standard has its own chemistry, impact test format, and delivery condition requirements. For cross-border tenders, always state the exact EN grade on the order and accept only the MTC showing the EN grade stamp.

9. Cost and Availability

Aspect	S235JR	S275JR	S355JR
Cost (per ton, indicative)	Base	+3-5%	+8-15%
Stock availability (Europe)	Excellent	Good (less common than S235/S355)	Excellent
Stock availability (China, Q235B/Q345B)	Q235B very common	Q275 rarely stocked	Q345B / Q355 very common
Lead time (stock sizes)	7-15 days	10-20 days	7-15 days
Total project cost (typical)	Higher tonnage; lower per-ton cost	Intermediate	Lower tonnage; higher per-ton cost; net cost lower for loaded structures

10. Selection Guide

Choose S235JR when:

The structure is non-critical or lightly loaded.
You need plate thicker than 150 mm or unusual sizes (S235 is more available in thicker plate).
You need maximum weldability and formability.
Local building code allows 235 MPa design.
Cost is the dominant factor.

Choose S275JR when:

The structure is moderately loaded and the project allows an intermediate strength.
You are working in markets where S275 is specified by local building code.
You want to balance cost and weight without jumping to S355.

Choose S355JR when:

The structure benefits from higher yield (long-span beams, high-rise columns, light-weight goals).
You want to reduce tonnage, welding, transport, and erection cost.
The design is per Eurocode 3 (EN 1993-1-1) which has dedicated S355 design tables.
The project is in a market where S355 is the default structural grade.

11. Common Procurement Errors

Stating “S235” without the impact grade. The supplier will default to S235JR (tested at +20°C). If your structure is in a cold climate, specify S235J2 (tested at -20°C) or move to EN 10025-3 fine-grain grades.
Accepting S355J0 as a substitute for S355J2. J0 is tested at 0°C; J2 is tested at -20°C. For cold-climate service, J2 is required. The MTC must state “J2” explicitly.
Confusing S235JR with Q235B. The chemistry is close, but the impact test format differs. EN 10025-2 requires the test per EN ISO 148-1; GB/T 700 requires a different sample geometry. Cross-acceptance requires a certified comparison report.
Not specifying delivery condition. For thicker plate, S355JR is typically delivered normalized (N) per EN 10025-2 clause 6.3. If you need TMCP for toughness, it must be agreed.
Not specifying plate tolerance class. EN 10029 Class A, B, C, or D applies. Class B is the default for most structural work. Specify Class C or D if your fabrication needs tighter thickness tolerance.

12. Sample Design Example

An industrial shed needs a 6-meter span simply-supported beam supporting a 25 kN/m uniform load.

S235JR design: Required plastic section modulus = M / fy = (25 x 6 x 6 / 8) x 10^6 / 235 = 479,000 mm3. IPE 270 provides 579,000 mm3 and weighs 36.1 kg/m.
S275JR design: Required Wpl = 410,000 mm3. IPE 240 provides 366,000 mm3 (insufficient); IPE 270 provides 579,000 mm3 (overkill). Next available is IPE 270 with 36.1 kg/m.
S355JR design: Required Wpl = 317,000 mm3. IPE 220 provides 285,000 mm3 (insufficient); IPE 240 provides 366,000 mm3 (sufficient). Weight = 30.7 kg/m.

Result: S355JR saves 5.4 kg/m (15%) over S235JR for the same span and load, at a per-ton premium of 8-15%. Net cost reduction is modest but weight saving in foundations and transport is significant.

13. Frequently Asked Questions

Q1: Is S235JR the same as ASTM A36?

Close but not identical. S235JR has minimum 235 MPa yield up to 16 mm and is Charpy tested at +20°C. A36 has 250 MPa minimum yield (36 ksi). The tensile envelopes are similar. For cross-border tenders, specify both grades on the MTC if dual certification is required.

Q2: Why is S275JR less common than S235 and S355?

Most designs either use the minimum acceptable strength (S235) for economy or jump to S355 for high-strength applications. S275 fills the middle but offers only a modest advantage over S235. Many mills produce S275 only on order.

Q3: Is S355JR suitable for low-temperature service?

S355JR is tested at +20°C. For service below +20°C, specify S355J0 (0°C) or S355J2 (-20°C). For service below -20°C, EN 10025-3 S355NL or EN 10025-4 S355ML is required.

Q4: Can S235JR be galvanized?

Yes. Hot-dip galvanizing per EN ISO 1461 is routine for S235JR. The silicon content (typically 0.15-0.30%) may produce a thicker coating. Confirm with the galvanizer if coating thickness control is critical.

Q5: What is the difference between S355JR and S355J2?

The strength is the same (355 MPa minimum yield up to 16 mm). The impact test temperature differs: JR is tested at +20°C, J2 at -20°C. J2 is for cold-climate or low-temperature service and costs slightly more.

Q6: Is S355JR equivalent to Q345B?

Close. Q345B (per GB/T 1591) has 345 MPa minimum yield up to 16 mm and is impact tested at +20°C. S355JR has 355 MPa yield and is tested at +20°C. For most structural applications, they are interchangeable, but verify chemistry and impact test format on the MTC.

14. Conclusion

S235JR, S275JR, and S355JR represent three strength tiers of EN 10025-2 non-alloy structural steel. The chemistry envelope and weldability are similar; the dominant difference is yield strength and the resulting weight and cost trade-off. S235 remains the economical default for general structural work, S275 is an intermediate choice for moderately loaded structures, and S355 is the modern structural grade for projects that benefit from reduced tonnage and lighter foundations. Selecting the right tier – and the right impact grade (JR, J0, J2) – early in design avoids costly mis-procurement, late substitution, and rejection at port of discharge.

Huaxia-Steel supplies EN 10025-2 S235JR, S275JR, S355JR (and J0/J2 impact grades) in plate, sections, and bars, with EN 10204 3.1 mill test certificates. Send your specification for a quote.