S235JR
1.0038
Hot-rolled non-alloy structural steel · EN 10025-2:2019 — technical delivery conditions for hot-rolled non-alloy structural steels · EN 10025-1 — general requirements used with EN 10025-2 for Construction Products Regulation applications
S235JR is the basic room-temperature-toughness grade in EN 10025-2. It combines a minimum yield strength of 235 MPa at thicknesses up to 16 mm with a specified Charpy V-notch energy of 27 J at +20 °C. It is widely used for general welded, bolted and fabricated steelwork, but its strength decreases with thickness, JR impact testing is not routinely verified unless ordered, and requirements such as cold-forming suitability, galvanizing chemistry, through-thickness properties and ultrasonic testing must be specified separately when needed.
- ReH ≥ 235 MPa for nominal thickness ≤ 16 mmStrength class · The guaranteed minimum falls progressively to 165 MPa for flat products above 250 mm through 400 mm.
- KV2 ≥ 27 J at +20 °CToughness quality · JR impact properties are verified by test only when specified at ordering under EN 10025-2 Option 3.
- 1.0038Material number · Do not confuse it with S235J0, S235J2 or cold-forming variants, which have different steel numbers.
- Hot-rolled flat and long productsProduct scope · EN 10025-2 does not cover structural hollow sections or tubes.
- CEV ≤ 0.35% through 40 mmWeldability control · The maximum rises to 0.38% above 40 through 150 mm and 0.40% above 150 through 400 mm.
- FN — rimming steel is not permittedDeoxidation · FN does not necessarily mean fully killed; compare with S235J2, for which FF is specified.
Overview
- Designation system
- EN 10027-1 steel name; EN 10027-2 steel number
- Product forms
- Hot-rolled plate and sheet, Hot-rolled strip and products cut from strip, Wide flats and flats, Structural sections, Bars and rod, Semi-finished products intended for further rolling into covered flat or long products
- Condition
- +AR — as rolled, +N — normalized or normalized rolled, +M — thermomechanically rolled; available for long products and hot-rolled strip, not quarto plate
- Density
- 7850 kg/m³ (Volumetric mass used by EN 10025-2 for calculating nominal product mass; not a heat-specific measured value.)
What the designation means—and what it does not mean
| Part | Meaning | Practical significance |
|---|---|---|
| S | Structural steel | The grade is designated primarily by mechanical properties and intended structural use. |
| 235 | Specified minimum yield strength in MPa for nominal thickness ≤ 16 mm | It is not a universal yield value: lower minima apply as product thickness increases. |
| JR | Minimum Charpy V-notch energy of 27 J at +20 °C | JR is the least demanding impact-temperature class in the S235 JR/J0/J2 series. |
S235JR is a complete grade and quality designation, not simply a generic name for mild steel. Compliance depends on the correct product standard, product form, thickness, delivery condition, chemistry, mechanical testing and inspection documentation. The grade does not define hardness, fatigue strength, corrosion resistance, elevated-temperature strength or guaranteed low-temperature toughness.
EN 10025-2 covers flat products of JR quality through 400 mm and S235 long products generally through 250 mm. Hollow sections are instead ordered to standards such as EN 10210-1 or EN 10219-1 and use related but distinct designations.
Specified chemical composition and weldability control
| Requirement | Nominal thickness | Maximum, mass % |
|---|---|---|
| C | ≤ 40 mm | 0.17 |
| C | > 40 mm | 0.20 |
| Mn | All covered thicknesses | 1.40 |
| P | All covered thicknesses | 0.035 |
| S | All covered thicknesses | 0.035 |
| N | All covered thicknesses | 0.012 |
| Cu | All covered thicknesses | 0.55 |
| Si | All covered thicknesses | Not specified for S235JR |
Heat analysis limits from EN 10025-2:2019. For sections thicker than 100 mm, maximum carbon is subject to agreement. P and S may each be 0.005 percentage points higher for long products. The nitrogen limit does not apply when sufficient aluminium or other nitrogen-binding elements are present and documented.
| Nominal thickness | Maximum CEV |
|---|---|
| ≤ 40 mm | 0.35% |
| > 40 to 150 mm | 0.38% |
| > 150 to 250 mm | 0.40% |
| > 250 to 400 mm | 0.40%; flat products only |
The CEV limits can be modified by specified options concerning copper alloying or chemistry for hot-dip galvanizing.
The relatively low carbon and CEV limits generally make S235JR straightforward to weld, but they do not justify an unconditional “no preheat required” rule. Welding procedure qualification and heat-input, hydrogen, preheat and interpass controls should follow the fabrication standard and EN 1011-2. Thickness, joint restraint, heat dissipation, consumable hydrogen level and actual ladle chemistry remain important, particularly in heavy or highly restrained joints.
Mechanical requirements depend on thickness and orientation
| Nominal thickness | Minimum ReH | Rm |
|---|---|---|
| ≤ 16 mm | 235 MPa | 360–510 MPa |
| > 16 to 40 mm | 225 MPa | 360–510 MPa |
| > 40 to 63 mm | 215 MPa | 360–510 MPa |
| > 63 to 80 mm | 215 MPa | 360–510 MPa |
| > 80 to 100 mm | 215 MPa | 360–510 MPa |
| > 100 to 150 mm | 195 MPa | 350–500 MPa |
| > 150 to 200 mm | 185 MPa | 340–490 MPa |
| > 200 to 250 mm | 175 MPa | 340–490 MPa |
| > 250 to 400 mm | 165 MPa | 330–480 MPa; flat products only |
For products below 3 mm, Rm is 360–510 MPa. For flat products, nominal thickness governs. For irregular long products, the thickness at the sampling location governs.
| Nominal thickness | Longitudinal A, L0 = 5.65√S0 | Transverse A, L0 = 5.65√S0 |
|---|---|---|
| 3 to 40 mm | 26% | 24% |
| > 40 to 63 mm | 25% | 23% |
| > 63 to 100 mm | 24% | 22% |
| > 100 to 150 mm | 22% | 22% |
| > 150 to 250 mm | 21% | 21% |
| > 250 to 400 mm | 21% | 21%; flat products only |
For plate, strip and wide flats at least 600 mm wide, transverse tensile values apply. For other products, longitudinal values apply. Products below 3 mm use an 80 mm gauge length and thickness-dependent elongation requirements.
The number 235 should therefore never be used without checking thickness. A 200 mm plate certified as S235JR has a specified minimum yield strength of 175 MPa, not 235 MPa. Design values must come from the applicable design code and product thickness rather than from the grade name alone.
Impact toughness: the critical JR qualification
| Test-piece orientation | Test temperature | Minimum average KV2 | Applicable thickness |
|---|---|---|---|
| Longitudinal | +20 °C | 27 J | Through 400 mm within the product-form scope |
For sections above 100 mm, impact values are to be agreed. Subsize specimens use proportionally reduced energy requirements. Product dimensions can prevent preparation of a required test piece.
The JR designation specifies an impact-energy level, but EN 10025-2 does not require routine verification of JR impact properties unless the purchaser invokes Option 3. If documented toughness is important, the order and inspection certificate must explicitly require the JR impact test.
A +20 °C Charpy requirement is not evidence of suitability for cold service. Structures exposed to low temperatures, thick highly stressed details, dynamic loading or significant brittle-fracture consequences may require S235J0, S235J2 or another grade selected through the applicable fracture-toughness rules.
Delivery condition, forming and thermal processing
| Condition | Description | Availability and consequence |
|---|---|---|
| +AR | As rolled | Permitted for long products, hot-rolled strip and quarto plate. |
| +N | Normalized or normalized rolled | Permitted for long products, strip and quarto plate; appropriate where subsequent hot forming or normalizing is planned within the standard's provisions. |
| +M | Thermomechanically rolled | Permitted for long products and hot-rolled strip, but not quarto plate. The resulting condition cannot generally be reproduced by heat treatment alone. |
Unless a condition is ordered, the manufacturer may select among the permitted conditions for the product form. EN 10025-2 mechanical requirements do not change with delivery condition.
Products supplied +AR or +M are not designated as suitable for hot forming under EN 10025-2. If properties must remain compliant after hot forming or normalizing, specify +N and control the operation using the applicable forming guidance. Stress relieving is accepted, but treatment above 580 °C or longer than one hour can reduce mechanical properties; for normalized or normalized-rolled flat products, the standard recommends a maximum stress-relief temperature of 560 °C unless properties after treatment are agreed with the producer.
Plain S235JR does not carry a guaranteed cold-forming suffix. When flangeability, roll forming or cold drawing is a contractual requirement, order the applicable C-grade or option rather than relying on general ductility. S235JRC, material number 1.0122, is the corresponding designation specifically identified for cold-forming applications.
Fabrication and service considerations
| Topic | What matters |
|---|---|
| Welding | Favorable base-metal chemistry, but welding controls must reflect actual CEV, thickness, restraint, consumable hydrogen and the qualified procedure. |
| Machining | Machinable by common operations; its ductility can produce long chips and less favorable surface finish. Modified sulphur chemistry for long products is an order option, not a default grade feature. |
| Cold forming | General ductility does not equal certified cold-forming suitability. Specify S235JRC or the appropriate forming option and bend requirements. |
| Galvanizing | Coating behavior depends strongly on silicon and phosphorus, neither of which is adequately controlled merely by ordering S235JR. Agree galvanizing chemistry using the EN 10025-2 option and relevant galvanizing standards. |
| Corrosion | S235JR has no enhanced atmospheric-corrosion resistance. Painting, galvanizing or another protection system is normally required where corrosion is credible. |
| Through-thickness loading | Z-quality under EN 10164 is optional and should be specified where lamellar-tearing risk or significant through-thickness strain exists. |
| Internal soundness | Ultrasonic testing is optional and must be ordered with the applicable acceptance standard and class. |
| Fatigue and elevated temperature | The grade designation supplies neither an S–N curve nor elevated-temperature design strength. Use the applicable design code and project requirements. |
Specifying and purchasing S235JR correctly
A technically complete order should identify the product, not just the grade. At minimum, specify quantity; product form; dimensions; the dimensional and tolerance standard; EN 10025-2 and S235JR or 1.0038; any required delivery condition; inspection-document type under EN 10204; and all project-specific options.
| Requirement | Ordering action |
|---|---|
| Verified JR toughness | Invoke EN 10025-2 Option 3 and ensure the inspection document reports the Charpy results and test temperature. |
| Product analysis | Specify Option 2 and the required sampling frequency. |
| Delivery condition | Specify +AR, +N or +M where processing or project rules require a particular condition. |
| Cold forming | Order the appropriate C-grade or forming option, with the relevant product and thickness limits. |
| Hot-dip galvanizing | Specify the required chemistry category or composition agreement; do not infer suitability from grade alone. |
| Through-thickness ductility | Specify an EN 10164 Z-class where required. |
| Ultrasonic examination | Specify the applicable product-specific UT standard and acceptance class. |
| Surface quality | Specify any class differing from the EN 10025-2 defaults for plate, sections, bars or rod. |
| Plate thickness tolerance | Confirm the applicable EN 10029 class or the tolerance standard for products cut from strip. |
| Traceability and certification | State the EN 10204 document required by the fabrication standard, design code or purchaser. |
For structural construction products subject to European regulatory requirements, EN 10025-2 is used with EN 10025-1. Fabrication and execution requirements may additionally dictate certification, traceability, weldability and inspection provisions.
Substitution and identification risks
A designation appearing in a comparison table is not automatically interchangeable with S235JR. Substitution must account for the governing product specification, product form, thickness-dependent strength, impact-testing temperature and verification, chemistry and CEV, delivery condition, tolerances, inspection document and regulatory status.
ASTM A36, JIS SS400 and Chinese Q235 grades are often described commercially as counterparts, but they are governed by different specifications and do not automatically reproduce the S235JR chemistry, Charpy requirement, thickness ranges or inspection provisions. They should not be substituted solely from a cross-reference table.
Sources
- BS EN 10025-2:2019 — Hot rolled products of structural steels: Technical delivery conditions for non-alloy structural steelsBritish Standards Institution
- DIN EN 10025-2:2019-10 — Hot rolled products of structural steels, Part 2DIN Media
- NEN-EN 10025-2:2019 — Technical delivery conditions and scopeRoyal Netherlands Standardization Institute
- BS EN 10025 series — Hot rolled products of structural steelsBritish Standards Institution
- Structural steels product catalogueArcelorMittal
- S235JR / 1.0038 properties for hot stripthyssenkrupp Materials Processing Europe
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