Gangsteel supplies EN 10025-3 S420N steel plate for heavily loaded welded structures designed around the 420 MPa nominal yield class. Fine-grain steelmaking and the normalized delivery route are part of the specification; the grade is not defined by yield strength alone. Within the EN 10025-3 steel plate family, we coordinate mill production, plate processing and export supply around the requirements of each project.
The 420 MPa minimum yield strength applies to nominal thickness up to 16 mm. For heavier plate, the specified minimum reduces in steps, reaching 320 MPa at over 200–250 mm. The N quality normally uses longitudinal Charpy V-notch verification at −20 °C. EN 10025-3 S420NL has the same tensile-property requirements at a given thickness but a different impact-quality specification; neither designation should be substituted without technical approval.
Grade Designation
- EN 10025-3 — technical delivery conditions for normalized/normalized-rolled weldable fine-grain structural steels.
- S — structural steel.
- 420 — minimum yield strength in MPa for nominal thickness ≤16 mm.
- N — quality with specified minimum impact energies down to −20 °C; the standard delivery route is normalized or normalized rolled.
- Steel number 1.8902 — numerical designation listed in the 2019 edition.
Common written forms include EN10025-3 S420N, EN 10025-3 S420 N and S420N. These spacing variants refer to the same grade, not separate specifications. Use the complete designation and standard edition on the purchase order.
Key Advantages of EN 10025-3 S420N Steel Plate
- 420 MPa nominal yield class with clearly defined, thickness-dependent acceptance values.
- 40 J minimum average longitudinal Charpy energy at −20 °C on full-size specimens under the normal test arrangement.
- Fully killed fine-grain steel with normalized or normalized-rolled delivery specified by the material standard.
- Strategic partnerships with domestic steel mills support production coordination and competitive pricing.
- In-stock inventory of commonly used plate specifications supports fast delivery; confirm the exact grade, dimensions and availability at quotation.
- Plate processing includes bending, beveling, cutting of special-shaped parts and further deep processing to the agreed drawings.
Chemical Composition (Heat Analysis, Maximum %)
| Element | Heat analysis, mass % |
|---|---|
| C | 0.20 max |
| Si | 0.60 max |
| Mn | 1.00–1.70 range |
| P | 0.030 max |
| S | 0.025 max |
| Nb | 0.05 max |
| V | 0.20 max |
| Al total | 0.02 min, subject to nitrogen-binding exception |
| Ti | 0.05 max |
| Cr | 0.30 max |
| Ni | 0.80 max |
| Mo | 0.10 max |
| Cu | 0.55 max |
| N | 0.025 max |
Values are from EN 10025-3:2019, Table 1, for flat products. Manganese is specified as a range; total aluminium is a minimum rather than a maximum. The other individual entries are maximum limits. The minimum total aluminium content does not apply if sufficient other nitrogen-binding elements are present. These are specification limits, not typical heat analyses; product-analysis limits are defined separately in Table 2.
Mechanical Properties
| Nominal plate thickness | Yield strength ReH min, MPa | Tensile strength Rm, MPa | Elongation A min, % |
|---|---|---|---|
| ≤16 mm | 420 | 520–680 | 19 |
| >16–40 mm | 400 | 520–680 | 19 |
| >40–63 mm | 390 | 520–680 | 19 |
| >63–80 mm | 370 | 520–680 | 18 |
| >80–100 mm | 360 | 520–680 | 18 |
| >100–150 mm | 340 | 500–650 | 18 |
| >150–200 mm | 330 | 500–650 | 18 |
| >200–250 mm | 320 | 500–650 | 18 |
Room-temperature tensile properties follow Table 4 of the 2019 edition. Elongation uses a proportional gauge length L₀ = 5.65√S₀. For plate, strip and wide flats of width ≥600 mm, these tensile-property values apply transverse to the rolling direction; for other products Table 4 specifies the longitudinal direction. Buyers should confirm the applicable standard edition, ordered thickness, specimen orientation and acceptance values on the purchase order and mill certificate.
| Charpy V-notch test temperature, °C | Longitudinal KV2 minimum average, J |
|---|---|
| +20 | 55 |
| 0 | 47 |
| −10 | 43 |
| −20 | 40 |
Table 5 gives the longitudinal impact values above. Unless otherwise agreed, verification is at −20 °C for N quality. These full-size specimen values are averages of three tests; the individual-result and retest rules of Clause 10.2.2 also apply. For subsize specimens, the minimum energy is reduced in direct proportion to specimen cross-sectional area. For flat products below 6 mm nominal thickness, impact tests are not required by Clause 9.2.3.3. Transverse impact testing is an order option with different energy values in Table 6; do not apply the longitudinal values to transverse specimens. A Charpy test temperature is not by itself an approved minimum service temperature.
Delivery Condition and Fabrication
The specified delivery condition is normalized or an equivalent condition obtained by normalizing rolling. EN 10025-3 is not a quenched-and-tempered specification. The mill certificate should identify the actual supply condition and agreed order options.
For grades with minimum yield strength ≥420 MPa, Clause 6.3 permits delayed cooling or additional tempering after normalizing or normalizing rolling; if used, that treatment is to be recorded in the inspection document. This provision does not turn the grade into an EN 10025-6 Q-grade.
Weld procedure qualification, consumable selection, preheat, forming and any subsequent heat treatment require review for the actual thickness, heat chemistry, restraint and project design rules. No universal welding or post-weld heat-treatment procedure is implied by the grade designation.
Carbon Equivalent
| Nominal thickness | Maximum CEV, heat analysis % |
|---|---|
| ≤63 mm | 0.48 |
| >63–100 mm | 0.50 |
| >100–250 mm | 0.52 |
These are the base limits in Table 3, calculated using the IIW formula CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15. Under the controlled-silicon provisions of Clause 7.2.4, the maximum CEV is increased by 0.02 for Si ≤0.04%, or by 0.01 for Si ≤0.25%, as applicable; these are alternative adjustments, not cumulative additions. Confirm any such order arrangement and the actual heat CEV before planning fabrication.
EN 10025-3 Grade Comparison
| Official grade | Yield min at ≤16 mm, MPa | Tensile strength at ≤100 mm, MPa | Longitudinal Charpy minimum average, full size |
|---|---|---|---|
| EN 10025-3 S275N | 275 | 370–510 | 40 J at −20 °C |
| EN 10025-3 S275NL | 275 | 370–510 | 27 J at −50 °C |
| EN 10025-3 S355N | 355 | 470–630 | 40 J at −20 °C |
| EN 10025-3 S355NL | 355 | 470–630 | 27 J at −50 °C |
| EN 10025-3 S420N | 420 | 520–680 | 40 J at −20 °C |
| EN 10025-3 S420NL | 420 | 520–680 | 27 J at −50 °C |
| EN 10025-3 S460N | 460 | 540–720 | 40 J at −20 °C |
| EN 10025-3 S460NL | 460 | 540–720 | 27 J at −50 °C |
Comparison basis: EN 10025-3:2019, Tables 4 and 5. Yield values here apply only at ≤16 mm; tensile ranges apply at ≤100 mm. All eight grades are covered through nominal thickness 250 mm in this edition, but thicker-plate strength values must be taken from the relevant thickness band. N and NL of the same strength class share tensile requirements, while their toughness specifications and some chemistry limits differ. This table is a grade-selection guide, not a stock list or substitution approval.
Available Dimensions
- Standard thickness scope: nominal thickness ≤250 mm under the 2019 edition; this is a standard coverage limit, not a claim that every thickness is in stock.
- Actual thickness × width × length, dimensional tolerances and production availability: confirm against the project specification and selected mill capability.
- State quantity, delivery condition, testing requirements, inspection documentation and processing allowance in the enquiry.
Main Applications
- Heavily loaded bridge and building components designed for this nominal strength class.
- Welded machinery frames, crane-support structures and engineered load-bearing assemblies.
- Structural support plates and fabricated members where section design and toughness requirements justify this grade.
N quality provides the specified −20 °C longitudinal impact verification under the normal test arrangement. Use in any structure remains subject to the designer’s assessment of temperature, stress state, thickness, fatigue, connections and the applicable construction code. This is a structural steel specification, not automatic approval for pressure-vessel service.
Equivalent Grades of EN 10025-3 S420N
No direct cross-standard equivalent is asserted for EN 10025-3 S420N. The closest comparison within the same strength class is EN 10025-3 S420NL, but a different N/NL quality is not an automatic equivalent. NL quality has a different impact specification and tighter phosphorus and sulfur limits; a nominal toughness upgrade still requires approval against the complete order.
Grades under EN 10025-2, thermomechanically rolled grades under EN 10025-4 and quenched-and-tempered grades under EN 10025-6 follow different delivery specifications. A matching strength number does not establish equivalence. Any substitute requires designer and purchaser approval after comparing chemistry, thickness-dependent strength, toughness, delivery condition, fabrication requirements and the applicable code edition.
Related Products
- EN 10025-3 steel plate — family page
- EN 10025-3 S275N steel plate
- EN 10025-3 S275NL steel plate
- EN 10025-3 S355N steel plate
- EN 10025-3 S355NL steel plate
- EN 10025-3 S420NL steel plate
- EN 10025-3 S460N steel plate
- EN 10025-3 S460NL steel plate
- EN 10025-2 steel plate
- EN 10025-4 steel plate — thermomechanically rolled family
- EN 10025-6 steel plate — quenched-and-tempered family
- Low-alloy and high-strength steel plate
Frequently Asked Questions (FAQ)
What is EN 10025-3 S420N (EN10025-3 S420N) steel plate?
It is a weldable fine-grain structural steel supplied normalized or normalized rolled. The grade belongs to the 420 MPa nominal yield class and the N impact quality; the complete thickness-dependent requirements matter more than the grade number alone.
Does EN 10025-3 S420N have the same yield strength at every thickness?
No. The minimum starts at 420 MPa for nominal thickness ≤16 mm and becomes 320 MPa at >200–250 mm. Tensile strength and elongation must also be checked against their own thickness bands.
What impact test applies to EN 10025-3 S420N?
The normal verification is longitudinal Charpy V-notch testing at −20 °C, with 40 J minimum average on full-size specimens. Subsize specimens, thin products and agreed transverse testing require the applicable standard rules; a test temperature alone does not establish allowable service temperature.
Is EN 10025-3 S420N quenched and tempered?
No. The specified route is normalizing or normalizing rolling. A plate ordered to a quenched-and-tempered specification belongs to a different delivery-standard family and cannot be treated as identical solely because its nominal yield class matches.
Can EN 10025-3 S420N be welded and processed?
It is specified as a weldable structural steel, but a qualified fabrication procedure must address actual chemistry, thickness, joint restraint and project rules. Gangsteel can coordinate bending, beveling, special-shaped cutting and further processing to an agreed drawing without assuming a universal welding or heat-treatment schedule.
Can another grade replace EN 10025-3 S420N?
Only with approval. S420NL is a useful same-strength comparison, not an unconditional equivalent. Check the full material specification, impact quality and design-code acceptance before changing the order.
What should an enquiry for EN 10025-3 S420N include?
Provide the standard edition, complete grade, thickness × width × length, quantity, delivery condition, impact-test requirements, inspection documentation and processing drawings. We will confirm exact grade and size availability, production or stock supply, price and delivery against that enquiry.
For production, processing and export enquiries for EN 10025-3 S420N steel plate, please contact Gangsteel with your specification and quantity.