S355J0
1.0553
Hot-rolled non-alloy structural steel · EN 10025-2:2019 — Technical delivery conditions for hot-rolled non-alloy structural steels · EN 10025-1:2004 — General technical delivery conditions for hot-rolled structural steel products
S355J0 is a general-purpose weldable structural steel with a nominal minimum yield strength of 355 MPa at thicknesses up to 16 mm and a specified Charpy V-notch energy of 27 J at 0 °C. Its strength decreases with increasing product thickness, and the designation alone does not define delivery condition, dimensional standard, inspection document, surface quality, through-thickness properties or suitability for cold forming. These items must be addressed separately when they matter to design or fabrication.
- S = structural steel; 355 = minimum yield strength in MPa for t ≤ 16 mm; J0 = 27 J Charpy V at 0 °CDesignation meaning · The J0 test temperature is not a universal minimum service temperature.
- 1.0553Steel number · The cold-forming grade S355J0C has a different steel number: 1.0554.
- Minimum yield strength falls from 355 MPa at t ≤ 16 mm to 265 MPa at 250 < t ≤ 400 mmThickness effect · The 250–400 mm range applies to flat products within the standard's scope.
- Minimum 27 J at 0 °C on longitudinal Charpy V-notch specimensImpact requirement · Specimen-size and product-dimension limitations apply.
- +AR, +N or +M depending on product form and orderDelivery condition · Quarto plate is limited to +AR or +N.
- 0.45% to 0.49%, depending on thicknessMaximum CEV · CEV is based on heat analysis and is an input to—not a substitute for—welding procedure control.
Overview
- Designation system
- Steel name according to EN 10027-1; steel number according to EN 10027-2
- Product forms
- Flat products: plate, sheet, hot-rolled strip and wide flats, Long products: structural sections, merchant bars and rods, Semi-finished products intended for conversion to compliant flat or long products, subject to agreement
- Condition
- +AR — as rolled, +N — normalized or normalized rolled, +M — thermomechanically rolled; available for long products and hot-rolled strip, but not for quarto plate
- Density
- 7850 kg/m³ (Volumetric mass specified by EN 10025-2 for calculating nominal product mass; it is not a heat-specific measured density.)
What the designation covers
S355J0 is one quality within the S355 family of non-alloy structural steels in EN 10025-2. The S355 qualities share the same basic room-temperature tensile-property table but differ principally in specified impact performance and some chemical limits. S355J0 requires 27 J at 0 °C, placing it between S355JR, tested at +20 °C, and S355J2, tested at −20 °C.
EN 10025-2 covers hot-rolled flat and long products. It does not cover finished structural hollow sections or tubes; designations such as S355J0H belong to hollow-section product standards and should not be treated as alternative spellings of S355J0. Product geometry, dimensions and tolerances are controlled by the applicable dimensional standard rather than by the grade name alone.
For S355J0, EN 10025-2 extends to 400 mm for flat products and generally to 250 mm for long products. Actual mill availability is normally much narrower and must be confirmed separately.
Chemical composition and weldability controls
| Element or control | Requirement, mass % | Applicability or qualification |
|---|---|---|
| C | 0.20 max. | Nominal thickness ≤ 30 mm |
| C | 0.22 max. | Nominal thickness > 30 mm |
| Si | 0.55 max. | All applicable thicknesses |
| Mn | 1.60 max. | All applicable thicknesses |
| P | 0.030 max. | Long products may be permitted 0.005 percentage points higher |
| S | 0.030 max. | Long products may be permitted 0.005 percentage points higher; a separately agreed machinability option can modify this limit |
| N | 0.012 max. | Limit does not apply when the specified amount of aluminium or other effective nitrogen-binding elements is present and reported |
| Cu | 0.55 max. | A controlled copper-alloyed option may be agreed for certain products |
| Deoxidation | FN | Rimming steel is not permitted |
These are grade limits for heat analysis, not a typical mill chemistry. Intentional additions not otherwise defined must be reported in the inspection document.
| Nominal thickness | C max., % | Si max., % | Mn max., % | P max., % | S max., % | N max., % | Cu max., % |
|---|---|---|---|---|---|---|---|
| ≤ 16 mm | 0.23 | 0.60 | 1.70 | 0.040 | 0.040 | 0.014 | 0.60 |
| > 16 to 30 mm | 0.23 | 0.60 | 1.70 | 0.040 | 0.040 | 0.014 | 0.60 |
| > 30 to 40 mm | 0.24 | 0.60 | 1.70 | 0.040 | 0.040 | 0.014 | 0.60 |
| > 40 mm | 0.24 | 0.60 | 1.70 | 0.040 | 0.040 | 0.014 | 0.60 |
Product analysis is performed only when specified at the time of ordering. The nitrogen exception and special provisions for long products also apply.
| Nominal product thickness | Maximum CEV |
|---|---|
| ≤ 30 mm | 0.45% |
| > 30 to 40 mm | 0.47% |
| > 40 to 150 mm | 0.47% |
| > 150 to 250 mm | 0.49% |
| > 250 to 400 mm | 0.49% |
For long products above 150 mm, a maximum CEV of 0.54% applies. Certain agreed copper-alloyed or galvanizing-chemistry options permit specified CEV increases.
Strength and ductility requirements
| Nominal thickness, mm | Minimum yield strength ReH, MPa | Tensile strength Rm, MPa |
|---|---|---|
| < 3 | 355 for t ≤ 16; then thickness-dependent as below | 510–680 |
| 3 to 16 | 355 | 470–630 |
| > 16 to 40 | 345 | 470–630 |
| > 40 to 63 | 335 | 470–630 |
| > 63 to 80 | 325 | 470–630 |
| > 80 to 100 | 315 | 470–630 |
| > 100 to 150 | 295 | 450–600 |
| > 150 to 200 | 285 | 450–600 |
| > 200 to 250 | 275 | 450–600 |
| > 250 to 400 | 265 | 450–600 |
The 250–400 mm range is relevant to flat products. ReH is the upper yield strength; where no yield phenomenon occurs, 0.2% proof strength is determined.
| Nominal thickness, mm | Longitudinal A, % | Transverse A, % |
|---|---|---|
| 3 to 40 | 22 | 20 |
| > 40 to 63 | 21 | 19 |
| > 63 to 100 | 20 | 18 |
| > 100 to 150 | 18 | 18 |
| > 150 to 250 | 17 | 17 |
| > 250 to 400 | 17 | 17 |
Values use proportional specimens with L0 = 5.65√S0. For plate, strip and wide flats at least 600 mm wide, transverse values normally apply; for other products, longitudinal values apply. Separate values and an 80 mm gauge length apply below 3 mm.
The number 355 is not a universal yield value for every S355J0 product. Design and purchasing documents must use the property value associated with the actual nominal thickness and product form.
Impact toughness and material selection
| Quality | Test-piece orientation | Test temperature | Minimum absorbed energy |
|---|---|---|---|
| S355J0 | Longitudinal | 0 °C | 27 J |
For flat products the 27 J requirement is specified through 400 mm. For sections above 100 mm, impact values must be agreed at the time of ordering.
J0 is a Charpy subgrade, not a statement that a component is automatically safe down to 0 °C. Selection against brittle fracture also depends on design temperature, thickness, stress level, detail category, strain rate, welding, residual stress and consequence of failure. The applicable structural design rules—such as EN 1993-1-10 where relevant—must be used to decide whether J0 provides sufficient toughness or whether J2, K2 or another specification is necessary.
Standard 10 mm × 10 mm Charpy specimens are used where product dimensions permit. Reduced-width specimens are used for thinner material, with the required energy reduced in direct proportion to specimen cross-sectional area. Impact testing is not required for flat products and sections below 6 mm nominal thickness, or for bars and rods below the dimensional thresholds stated by the standard.
Delivery condition and thermal processing
| Product route | Permitted conditions unless otherwise agreed | Practical significance |
|---|---|---|
| Long products and hot-rolled strip | +AR, +N or +M at the manufacturer's discretion | Specify the required condition if subsequent processing or engineering qualification depends on it. |
| Quarto plate | +AR or +N at the manufacturer's discretion | +M is not a delivery condition for quarto plate under EN 10025-2. |
| Products ordered in a defined condition | Condition appended to the designation, for example S355J0+N | The condition is also identified in the inspection document when one is required. |
The specified mechanical-property requirements do not change with delivery condition, but response to hot forming and subsequent heat treatment does.
These steels are not generally intended for heat treatment after delivery. Products supplied in +N may be normalized or hot formed after delivery while retaining the relevant normalized-condition requirements when the standard's processing provisions are followed. Products in +AR or +M should not be assumed suitable for hot forming.
EN 10025-2 warns that stress relieving above 580 °C or for more than one hour can reduce mechanical properties. For normalized or normalized-rolled flat products, the stated maximum stress-relief temperature is 560 °C. More severe treatments require agreement on post-treatment properties at the time of order.
Fabrication implications
S355J0 is intended to be weldable using established procedures for ferritic structural steels. EN 10025-2 refers arc-welding practice to EN 1011-2. Required preheat and heat-input controls cannot be selected from the grade name alone: they depend on actual heat chemistry and CEV, thickness, joint restraint, hydrogen level, process, consumables and ambient conditions. Increasing thickness and strength level increases susceptibility to hydrogen-assisted cold cracking.
Base grade S355J0 does not carry the standard's explicit cold-forming designation. Where guaranteed suitability for cold flanging or cold roll forming is required, specify S355J0C, steel number 1.0554, together with the applicable ordering option. Cold forming reduces ductility and may affect brittle-fracture resistance, especially where the formed component will subsequently be galvanized.
The base chemistry limits do not guarantee a particular zinc-coating appearance or growth rate. If galvanizing behaviour is important, use the EN 10025-2 ordering option for controlled silicon and phosphorus chemistry and specify the coating under EN ISO 1461. The steelmaker and galvanizer should be consulted before ordering rather than attempting to infer coating behaviour from the S355J0 designation.
S355J0 does not inherently include improved through-thickness ductility or ultrasonic inspection. For highly restrained welded details, thick T-joints or other configurations susceptible to lamellar tearing, consider an agreed EN 10164 Z-quality. Ultrasonic examination of plates, H/I sections or bars is also an ordering option and must be specified with the applicable acceptance standard and class.
The grade is machinable by conventional operations, but its ductility can produce less favourable chip formation and surface finish than free-machining steels. A higher-sulphur option for long products exists only by agreement and with sulphide-shape control; it should not be assumed from a standard S355J0 order.
Specifying and verifying an order
| Item | What to state or verify |
|---|---|
| Complete designation | EN 10025-2 — S355J0, or S355J0+AR/+N/+M when a particular permitted condition is required |
| Product and dimensions | Plate, strip, section, bar or other form; nominal dimensions; applicable dimensional and tolerance standard |
| Thickness-dependent properties | Confirm that design values correspond to the ordered nominal thickness |
| Inspection document | Specify the required EN 10204 document type; a 3.1 certificate should not be assumed unless ordered or required by the application standard |
| Impact testing | Confirm product dimensions permit testing and identify any special test frequency or parent-plate/coil requirements |
| Chemical documentation | Heat analysis and reported CEV; order product analysis if independent product-level verification is required |
| Fabrication options | Cold-forming designation, controlled galvanizing chemistry, through-thickness properties, ultrasonic testing or enhanced surface class where applicable |
| Traceability and compliance | Required marking, CE/UK conformity documentation where applicable, heat identity and traceability through cutting and fabrication |
| Application requirements | Check the relevant design, execution, welding and project specifications in addition to EN 10025-2 |
An order stating only “S355” is incomplete because it does not define the impact subgrade. An order stating only “S355J0” may still be incomplete where delivery condition, tolerance class, inspection certification, toughness selection or fabrication options are important.
Sources
- BS EN 10025-2:2019 — Hot rolled products of structural steels: Technical delivery conditions for non-alloy structural steelsBritish Standards Institution
- Declaration of Performance No. 1.0553 — S355J0Marcegaglia Plates
- BS EN 1011-2:2001 — Welding recommendations: Arc welding of ferritic steelsBritish Standards Institution
- BS EN 10204:2004 — Metallic products: Types of inspection documentsBritish Standards Institution
- BS EN 1993-1-10:2025 — Eurocode 3: Material toughness and through-thickness propertiesBritish Standards Institution
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