Structural steel S235JR, S275JR and S355J2: which grade for which application

S235JR, S275JR and S355J2. The three most common grades of non-alloy structural steel used in building construction, industrial halls and steel structures across Europe. The short answer to which grade you should choose: S235JR for light welded frames, gates and railings; S275JR for medium-load applications and halls up to 12 m span; S355J2 wherever you need higher yield strength while keeping good weldability. The long answer, which you need as a structural engineer or buyer, is in the tables below, with yield strength, chemical composition, the JR/J0/J2 toughness symbols and practical decision criteria.

This article is based on EN 10025-2 and on practical experience from the metals warehouse of ULAMEX (since 1988, certified to EN 1090-1 EXC2 and ISO 3834-2).

What you will learn from this article:

  1. What “structural steel” means under EN 10025-2
  2. A direct comparison of S235 vs S275 vs S355 (mechanical properties + chemical composition)
  3. When S235JR is enough, when to step up to S275JR, and when S355J2 is worth the price
  4. What the JR, J0 and J2 symbols mean (Charpy impact energy at different temperatures)
  5. Equivalences with ASTM A36 and A572 Grade 50 for trans-Atlantic readers
  6. What we keep in stock at our Zawada warehouse and in which dimensions
  7. When we do not recommend our structural steel: the boundary where you should call a specialist supplier

Who this article is for: structural design engineers, fabrication shop buyers, project managers in civil and industrial construction, and quantity surveyors choosing between S235, S275 and S355 for a specific project. If you are designing an industrial hall, a photovoltaic frame, an agricultural building or a refurbishment with legacy documentation, you will find technical answers and procurement guidance here.


1. What structural steel is and what EN 10025-2 says

Structural steel (German Baustahl, Polish stal konstrukcyjna) is a non-alloy general-purpose steel intended for welded, bolted or riveted structures. The standard that defines its mechanical properties, chemical composition and tolerances is EN 10025-2 (“Hot-rolled products of structural steels. Part 2: Technical delivery conditions for non-alloy structural steels”).

The grade designation has three parts:

  • S: Structural
  • 235 / 275 / 355: minimum yield strength ReH in N/mm² (MPa) for thickness ≤ 16 mm
  • JR / J0 / J2: minimum Charpy V-notch impact energy at a specified test temperature (see § 6)

Example: S235JR = structural steel with minimum yield strength 235 N/mm², guaranteed Charpy impact energy 27 J at +20 °C. The DIN material number (Werkstoffnummer) is 1.0038.

S275JR = 1.0044. S355JR = 1.0045. S355J2 = 1.0577.

In the ULAMEX warehouse at Zawada these four material numbers cover the overwhelming majority of stock movement. Any other grade (S420, S460, S690QL) is mill-order only.

1.1 Decoding the S235JR designation, character by character

PositionCodeMeaningExample
1SStructural (steel for load-bearing applications)S235, S275, S355
2-4235Minimum yield strength ReH in N/mm² for thickness ≤ 16 mm235, 275, 355 N/mm²
5JCharpy V-notch impact energy guaranteed at 27 JJ for 27 J, K for 40 J
6R / 0 / 2Charpy test temperatureR = +20 °C, 0 = 0 °C, 2 = −20 °C

Worked example: S355J2 = structural steel with minimum yield strength 355 N/mm² and minimum Charpy impact energy 27 J at −20 °C. DIN material number: 1.0577.

Source: EN 10025-2:2019, ULAMEX incoming inspection records.

1.2 Types of structural steel by application (taxonomy)

Structural steel is a broad term. In industrial practice we distinguish six basic categories that differ in carbon content, alloying elements and heat treatment.

TypeC contentCharacteristicTypical applications
General-purpose steel (S235, S275, S355)< 0.24 %Standard grade, good weldabilityBuildings, halls, bridges, gates, fences
Low-alloy steel (S420, S460, S550)< 0.22 %Higher yield strength via micro-alloying (Nb, V, Ti)Road and rail bridges, crane runways, wind turbine towers
Quality steel for heat treatment (C45, C60)0.40-0.60 %Suitable for hardening and temperingMachine parts, shafts, gears
Spring steel (54SiCr6, 60SiMnCr4)0.50-0.65 %High silicon content, high elasticityLeaf and coil springs, torsion bars
Free-cutting steel (11SMn30, 11SMnPb30)< 0.15 %Sulphur and lead added for easy machiningBolts, nuts, small turned parts
Case-hardening steel (16MnCr5, 20MnCr5)< 0.20 %For surface carburising and hardeningGears, pins, rolling bearings

This article focuses on the first category, general-purpose steel under EN 10025-2. Spring, free-cutting and case-hardening steels are covered by other standards (EN 10089, EN 10087, EN 10084), and at ULAMEX we keep stock only of the most common grades C45 and 11SMn30. For complex alloy steels we recommend a specialist distributor.


2. S235JR vs S275JR vs S355J2: three grades side by side

2.1 Mechanical properties (EN 10025-2, thickness ≤ 16 mm)

PropertyS235JRS275JRS355J2
Minimum yield strength ReH (N/mm²)235275355
Tensile strength Rm (N/mm²)360-510410-560470-630
Elongation at fracture A (%, min., L₀ = 5.65√S₀)262322
Charpy impact energy KV (J at test temperature)27 (+20 °C)27 (+20 °C)27 (−20 °C)
Material number (Werkstoffnummer)1.00381.00441.0577

Source: EN 10025-2:2019, ULAMEX incoming inspection records.

What this means in practice for the design engineer:

  • S275 has a yield strength 17 % higher than S235. At the same load, the cross-section can be roughly 14 % smaller.
  • S355 has a yield strength 51 % higher than S235. At the same load, the cross-section can be roughly 30 % smaller, which means lower mass and lower transport cost on large projects above 50 tonnes.

2.2 Chemical composition (maximum content, mass %)

ElementS235JRS275JRS355J2
C (carbon)0.170.210.22
Mn (manganese)1.401.501.60
Si (silicon)not specifiednot specified0.55
P (phosphorus)0.0350.0350.030
S (sulphur)0.0350.0350.030
N (nitrogen)0.0120.012not specified
Cu (copper)0.550.550.55
Carbon equivalent CEV≤ 0.35≤ 0.40≤ 0.45

Source: EN 10025-2:2019.

The implication for welding: all three grades have a CEV below 0.45, which means good weldability without preheat for thicknesses up to 30 mm. For S355J2 above 30 mm thickness we recommend a preheat of 100-150 °C, in line with EN 1011-2.

2.3 The practical choice: which grade for which job

SituationRecommended gradeWhy
Gates, fences, light frames, exterior staircasesS235JRSufficient strength, lowest cost, easy to weld
Garage doors, fence posts, spans up to 6 mS235JRSame as above
Industrial halls up to 12 m span, cranes up to 5 tS275JRBetter strength-to-cost ratio
Halls above 12 m, bridges, cranes above 5 tS355J2Higher yield strength means smaller cross-sections
Outdoor service below −20 °C (mountain climate)S355J2 (not JR)Toughness at sub-zero temperatures
Machine parts, fatigue loadingC45, 42CrMo4 (specialist steel)Not general-purpose structural steel

3. S235JR: when it is enough

S235JR is the most widely used non-alloy steel grade in Europe. In day-to-day practice at the ULAMEX warehouse, more than 70 % of enquiries for light welded structures are answered with S235JR.

Typical applications where S235JR is the right choice:

  • Gates, balustrades, exterior staircases on residential and small commercial buildings
  • Garage door frames, canopies, metal pergolas
  • Light agricultural structures: shelters, sheds, barns up to 8 m span
  • Fence posts, framed mesh panels
  • Mounting structures for residential photovoltaic systems (below 10 kW)
  • Conveyor frames, racking, technological tables and workstations

Advantages:

  • Lowest price among the three grades compared
  • Excellent weldability (CEV ≤ 0.35) with any process: SMAW (MMA), GMAW (MIG/MAG), GTAW (TIG)
  • Constant availability in all forms and thicknesses
  • Generous tolerance for minor execution deviations

Caveats:

  • Charpy impact energy is guaranteed only at +20 °C. For outdoor service at sub-zero temperatures, step up to S275JR or S355J2
  • Do not use S235JR under intense dynamic loading (vibration, repeated impact)
  • For thicknesses above 30 mm and welding, verify the CEV of the actual heat on the EN 10204 type 3.1 inspection certificate

4. S275JR: the reasonable compromise

S275JR has a yield strength 17 % higher than S235JR with practically identical weldability. In the ULAMEX warehouse, S275JR represents about 15 % of structural steel movement and is the preferred grade for projects where S235JR would be marginal and S355J2 would be over-specified.

Typical applications where S275JR is the right choice:

  • Industrial halls with 8 to 12 m span, moderate snow loading
  • Repairs and extensions of halls built in the 1990s and 2000s (often originally specified to BS 4360 Grade 43 or DIN St 44, both functionally equivalent to S275)
  • U and I sections up to 12 mm thickness for medium-load load-bearing structures
  • Mounting structures for photovoltaic farms between 10 and 100 kW
  • Trailer chassis, loading platforms, permanent scaffolding
  • Medium-sized agricultural structures: stables, hangars, light silos

Key argument: some legacy structural calculations from older British and continental projects were performed directly on S275-equivalent grades. For modernisation or extension of such structures, staying on the same grade is safer than recalculating everything for S235JR or S355J2.


5. S355J2: when the price difference is worth it

S355J2 has a yield strength 51 % higher than S235JR. At the same static load, this means a cross-section roughly 30 % smaller and proportionally lower mass. On large projects, halls above 1,000 tonnes, bridges and crane runways, the saving in mass more than covers the unit price difference (S355J2 is roughly 10 to 15 % more expensive per tonne than S235JR).

Typical applications where S355J2 is the right choice:

  • Steel structures for halls above 15 m span
  • Crane runways and supports for cranes above 5 t
  • Road and rail bridges (note: bridges generally require EN 10204 type 3.2 inspection certificates with an independent inspector)
  • Tower cranes and stationary mobile cranes
  • Industrial structures with dynamic loading
  • Wind turbine towers
  • IPE, HEA and HEB structural sections for heavy construction

Why J2 (not JR) for these applications:

  • Charpy impact energy 27 J at −20 °C (not just at +20 °C as for JR)
  • Reduced risk of brittle fracture in real winter conditions across Europe (frost frequently drops below −15 °C in continental zones)
  • A standard requirement for structures certified to EN 1090-1 EXC2 or EXC3

The +N variant: S355J2+N denotes steel rolled in the normalised condition (a heat treatment that homogenises the grain structure). For welded structures with thickness above 25 mm, or for service at temperatures below −20 °C, the +N variant is roughly 5 to 8 % more expensive than standard S355J2 but offers superior toughness.


6. The JR, J0 and J2 symbols: Charpy impact energy at different temperatures

The third part of the grade designation (a letter and a digit, e.g. JR, J0, J2, K2) describes the Charpy impact energy guaranteed at a specified test temperature. This parameter determines whether the steel resists brittle fracture in cold conditions.

SymbolTest temperatureMinimum Charpy impact energyPractical use
JR+20 °C27 JIndoor structures or mild climate
J00 °C27 JOutdoor structures without severe frost
J2−20 °C27 JOutdoor structures in continental Europe
K2−20 °C40 JHigh-toughness requirement (bridges, fatigue)

Source: EN 10025-2:2019, Table 8.

Recommendation for European service:

  • For buildings and outdoor halls below 600 m altitude, choose at least J0
  • For mountain zones (Alps, Carpathians, Scottish Highlands above 800 m) or outdoor service below −20 °C, choose J2
  • For bridges and structures certified to EXC3 and above, choose K2 or S355J2+N

A brittle fracture at −25 °C in a welded structure executed in S235JR (limited to +20 °C) is a risk that is not worth taking. The price difference between JR and J2 is below 5 % per tonne.


7. ASTM equivalents for trans-Atlantic readers

European EN 10025-2 grades have functional equivalents in the American ASTM system, although the equivalence is not exact. For projects where engineers from both jurisdictions specify materials, the equivalence table below is a practical reference.

7.1 Equivalence table EN 10025-2 vs ASTM

EN 10025-2 (current)ASTM (closest equivalent)Note
S235JRASTM A36A36 minimum yield is 36 ksi (≈ 248 N/mm²), slightly higher than S235 nominal. Functionally equivalent for most applications.
S275JRNo exact ASTM equivalentS275 sits between A36 (248 N/mm²) and A572 Grade 50 (345 N/mm²). UK practice retains S275 as a distinct grade.
S355J2ASTM A572 Grade 50A572 Gr 50 minimum yield is 50 ksi (≈ 345 N/mm²). S355 is marginally stronger and tougher (J2 specifies Charpy at −20 °C).
S355J2+NASTM A572 Grade 50 + normalisingNormalised heat treatment available on request from American mills.
S355K2ASTM A588 (weathering) or A992 (rolled sections)Closest match for high-toughness applications.

Sources: EN 10025-2:2019, ASTM A36/A572-21, ULAMEX technical reference.

7.2 Practical implications for procurement

  • Welding: EN 10025-2 grades follow EN 1011-2 procedures; ASTM grades follow AWS D1.1. Do not mix prequalified procedures across the two standards. Choose one and document it.
  • Inspection certificates: EN 10204 type 3.1 (mill test certificate) is broadly comparable to the American “mill test report”, though documentary requirements differ.
  • CE marking: structural components delivered to the EU and UK markets require CE marking under EN 1090-1. ASTM grades alone do not satisfy CE marking requirements without additional documentation.
  • Post-Brexit context: the United Kingdom continues to use EN 10025-2 (as BS EN 10025-2). The UKCA marking is being phased in, but EN 1090-1 certification remains accepted for structural steel components under the UK-EU Trade and Cooperation Agreement.

8. What we stock at our Zawada warehouse (S235/S275/S355)

ULAMEX holds at the Zawada warehouse (Poland) several thousand tonnes of structural steel available for immediate dispatch. Typical lead times to the United Kingdom are 5 to 9 working days, to Germany and the Benelux 2 to 4 working days, to Scandinavia 4 to 7 working days.

ProductGrades in stockDimensions (mm)Length (mm)Indicative stock
Hot-rolled plateS235JR, S275JR, S355J2thickness 1.5 / 2 / 3 / 4 / 5 / 6 / 8 / 10 / 12 / 15 / 201500 × 3000, 2000 × 6000~80 t
Square hollow sectionsS235JR20×20×2 to 100×100×56000~25 t
Rectangular hollow sectionsS235JR30×20×2 to 120×80×56000~18 t
Flat barS235JR20×3 to 120×206000~12 t
Equal-leg L-anglesS235JR20×20×3 to 100×100×106000~15 t
Unequal-leg L-anglesS235JR30×20×3 to 100×65×86000~8 t
U-channels (UPN, UPE)S235JR, S355J2UPN 50 to UPN 3006000-12000~22 t
I-beams (IPE, HEA, HEB)S235JR, S355J2IPE 80 to HEB 3006000-12000~35 t

Source: current ULAMEX warehouse stock at Zawada, verified 2026-04-27. Stock figures are indicative; for large quantities above 50 tonnes per grade and section, please confirm availability at the time of enquiry.

Technical note: the EN 10204 type 3.1 inspection certificate is available on request for any delivery. For bridges and structures requiring type 3.2 certification (with an independent inspector, e.g. Lloyd’s, TÜV or RINA), the order must be flagged in advance and the lead time extends by 5 to 7 working days.


9. When we do not recommend our structural steel

The editorial manifesto of the ULAMEX academy includes a rule that other distributors do not always observe: we tell you when we cannot help you. We believe that an honest answer about when not to buy from us brings you back when we can genuinely help.

1. Road and rail bridges with EN 10204 type 3.2 certification and an independent inspector. ULAMEX delivers type 3.1 (mill) certificates as standard. For type 3.2 certification with an independent inspector (Lloyd’s, TÜV, RINA), the lead time extends significantly and the cost increases. For large bridge projects we recommend a specialist distributor with an established type 3.2 inspection workflow.

2. Nuclear energy, offshore structures, military vehicles. These applications use specific grades (S355G7+N, RAFM steels, high-specification austenitic stainless steels). ULAMEX does not stock these grades and does not have nuclear qualification flow. Use a specialist distributor in energy or contact the producing mill directly.

3. Machine parts under fatigue loading or wear. Drive shafts, gear teeth, load-bearing pins, sprockets are not built from general-purpose structural steel. Use C45 (quenched and tempered), 42CrMo4 (heat-treatable) or 16MnCr5 (case-hardening). ULAMEX keeps stock of C45 and 11SMn30 only for occasional enquiries; for complex alloy steels, use a specialist distributor.

4. Aggressive corrosive environments: marine atmosphere, aggressive chemical industry. Non-alloy structural steel rusts. For atmosphere with high salinity (within 2 km of the coast) or for direct contact with acids, choose stainless steel (1.4301, 1.4404, 1.4571) or hot-dip galvanised steel to EN ISO 1461. ULAMEX stocks stainless steel and offers hot-dip galvanising through partners in southeast Poland, but for an integrated galvanising-painting-passivation workflow, a local specialist in the destination country is more efficient.

5. Orders above 200 tonnes per grade with delivery in under 5 working days. For large urgent quantities, our transport capacity may be limited. If the deadline is critical, we recommend comparing with other sources, for example Salzgitter Mannesmann (Germany), Aalco or Metals4U (United Kingdom), Ferona (Czech Republic). For large quantities planned 14 to 21 days in advance, ULAMEX is competitive on both price and lead time.

6. Very small quantities below 100 kg total. ULAMEX is a wholesale supplier. For small quantities we recommend specialist retailers in your local market (in the UK: metals4u.co.uk, m-machine-metals.co.uk; in Germany: edelstahl-witzenmann.de, allmetal.de). You will pay 30 to 50 % more per kilogram but you avoid a disproportionate transport cost. At ULAMEX the indicative minimum order quantity for structural steel starts at around 500 kg for deliveries within Europe.


10. How to order from ULAMEX

The ordering process is direct, with no unnecessary bureaucracy.

Step 1. You send a request for quotation

  • Email: [email protected]
  • Telephone: +48 504 424 761 (Mon-Fri 08:00-16:00 CET, 07:00-15:00 UK time)
  • We speak English on every channel; for technical detail in Polish, German or Czech we have native-speaking representatives

Step 2. You specify:

  • Grade (S235JR / S275JR / S355J2)
  • Form (plate, section, tube, angle, flat bar, round bar)
  • Dimensions (thickness, width, length)
  • Quantity in kilograms or tonnes
  • Inspection certificate required (standard 3.1, or 3.2 with independent inspector for bridges)
  • Delivery destination (city + postcode)

Step 3. You receive a quotation within 24 working hours

  • Price per tonne for each line item
  • Estimated lead time
  • Transport cost (DAP to your site or FCA Zawada)

Step 4. You confirm the order

  • You return the signed confirmation by email
  • Payment terms: bank transfer, agreed terms (30 days standard for verified accounts; pro-forma for first-time customers)

Step 5. Warehouse pick and dispatch

  • The material is prepared at the Zawada warehouse within 1 to 3 working days
  • Dispatch with CMR consignment note
  • Typical transport lead time Poland to United Kingdom: 5 to 9 working days
  • For urgent cases, same-day dispatch from order confirmation (limited capacity, please confirm individually)

Step 6. Documentation reaches you

  • Type 3.1 mill test certificate to EN 10204 delivered as PDF by email plus signed original on delivery
  • CMR consignment note, VAT invoice (intra-EU B2B reverse charge)
  • On request: additional certificates of conformity, Declaration of Performance for EXC2 components

Additional services on request:

  • Cut-to-length service at the Zawada warehouse (tolerance ±0.5 mm typical)
  • CNC plasma cutting for complex shapes (DXF or PDF input)
  • Welded assemblies certified to EN 1090-1 EXC2 and ISO 3834-2

11. Frequently asked questions

1. What is structural steel?

Structural steel is a non-alloy general-purpose steel intended for welded, bolted or riveted structures. EN 10025-2 defines five basic grades: S235, S275, S355, S420 and S460. In British and European practice, S235JR, S275JR, S355JR and S355J2 are most common and together cover roughly 95 % of construction and fabrication applications.

2. What does S235JR mean?

Letter-by-letter decoding: S = structural, 235 = minimum yield strength ReH in N/mm² for thickness ≤ 16 mm, J = minimum Charpy impact energy 27 J, R = test temperature +20 °C. DIN material number: 1.0038. Closest ASTM equivalent: A36.

3. What does the J2 in S355J2 mean?

J2 = guaranteed Charpy impact energy 27 J at −20 °C test temperature. JR = +20 °C, J0 = 0 °C, K2 = −20 °C with 40 J. For outdoor service in continental Europe we recommend at least J0; for mountain zones or for structures certified to EXC3, choose J2.

4. What is the difference between S235 and S355?

Yield strength: 235 vs 355 N/mm², which is 51 % higher for S355. At the same static load, the cross-section can be roughly 30 % smaller for S355, which means lower mass. S355 is roughly 10 to 15 % more expensive per tonne, but more economical on large projects (above 50 tonnes).

5. Can S235 and S355 be welded together?

Yes. Both have CEV ≤ 0.45 and use identical welding technology (GMAW / GTAW / SMAW). The welding procedure follows the higher-yield grade (S355). The joint strength, however, is governed by the weaker grade (S235). Always verify the static calculation for the mixed joint.

6. What is an EN 10204 type 3.1 inspection certificate?

A type 3.1 certificate is a mill test certificate issued by the producer with the actual chemical and mechanical test results for the specific heat. A type 3.2 certificate is a type 3.1 plus an independent inspector (Lloyd’s, TÜV, RINA), required for bridges and public infrastructure. ULAMEX delivers type 3.1 certificates on request as standard; type 3.2 is available on advance order with extended lead time.

7. Can I substitute S235JR for S355J2 in an industrial hall?

Not without recalculating the structure. The lower yield strength of S235JR means larger cross-sections for the same load. A grade change requires a fresh static calculation and the written approval of the structural engineer of record. For halls above 12 m span, S355J2 is almost always the correct choice.

8. Which is the strongest structural steel?

Among the three grades compared, S355J2 is the strongest at 355 N/mm² yield. Across the full EN 10025-2 family: S460 (460 N/mm²), S550 (550 N/mm²), S690QL (690 N/mm² after quench-and-temper). Grades above S355 are mill-order only and not held in standard ULAMEX stock.

9. What does +N mean in the designation S355J2+N?

+N indicates normalised rolling, a heat treatment that homogenises the grain structure. It improves toughness and is essential for welded structures with thickness above 25 mm or for service below −20 °C. S355J2+N is roughly 5 to 8 % more expensive than standard S355J2.

10. What are the ASTM equivalents of S235, S275 and S355?

EN gradeClosest ASTM equivalentDIN material number
S235JRA361.0038
S275JR(no exact equivalent; sits between A36 and A572 Gr 50)1.0044
S355JRA572 Grade 501.0045
S355J2A572 Grade 50 (with normalising or impact testing)1.0577

The Werkstoffnummer is used for imports from German and Austrian mills. ASTM equivalents are useful when working with American engineers or contractors, but EN 10025-2 designations remain canonical for the United Kingdom and the European Union.


12. Related products from the ULAMEX Zawada warehouse

For projects that use structural steel S235/S275/S355, please also consider the complementary products available in stock:

  • Square and rectangular hollow sections, S235JR, dimensions from 20×20 to 120×80, for frames and light welded structures
  • U-channels UPN and UPE, S235JR and S355J2, for industrial halls and crane supports
  • I-beams IPE, HEA and HEB, S235JR and S355J2, lengths 6 m and 12 m, for primary load-bearing structures
  • Chequer plate (anti-slip plate), S235JR, for floors, stairs and platforms
  • Hot-dip galvanised L-angles, S235JR with EN ISO 1461 zinc coating, for aggressive outdoor environments
  • Flat bar, S235JR, dimensions 20×3 to 120×20, for welded parts and reinforcements
  • Stainless plate 1.4301, for corrosion-resistant applications (food, chemical industry)
  • Aluminium profiles EN AW-6060 T6, an alternative for light structures with weight constraints

For the full product range and current availability, please see our black steel category or request a quotation for a combined grade order.


Related guides: EN 10219 hollow sections, 304 and 316 stainless steel and EN AW aluminium alloys.

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