Gangsteel supplies EN 10025-4 S420M steel plate for welded structural projects that specify the 420 MPa nominal yield class in the thermomechanically rolled (M) delivery condition, with M-quality impact performance at −20 °C. It is a weldable fine-grain structural steel, not a normalized EN 10025-3 grade and not a quenched-and-tempered EN 10025-6 grade. Within the EN 10025-4 steel plate family, we coordinate mill production, plate processing and export supply around the requirements of each project.
The numerical chemistry, tensile, carbon-equivalent and impact tables on this page are taken from the official EN 10025-4:2004 text (BS EN 10025-4:2004), a verified older edition obtained in full. The current published edition is EN 10025-4:2019+A1:2022 (BS EN 10025-4:2019+A1:2022, published 30 April 2023 and listed Current by BSI). Amendment A1:2022 does not change the chemistry or mechanical tables; it updates foreword references and adds a sentence in 9.2.3.2. The 2019 edition extends the general thickness scope to ≤ 150 mm and adds S500M and S500ML; those two grades are not existing Gangsteel product pages and are not invented here. A complete 2019 table set for the 120–150 mm flat-product band was not independently obtained, so this page does not state unverified values for that band. A 2026 revision remains a project (prEN 10025-4 rev) and is not a published edition. The purchase order, mill certificate and contractual edition govern.
Grade Designation
- EN 10025-4 — technical delivery conditions for thermomechanically rolled weldable fine-grain structural steels.
- S — structural steel.
- 420 — minimum yield strength in MPa for nominal thickness ≤ 16 mm.
- M — thermomechanically rolled delivery, with specified minimum impact energy at temperatures not lower than −20 °C.
- Steel number 1.8825 — numerical designation listed in EN 10025-4:2004 (and unchanged in the 2019 designation example style).
Common written forms include EN10025-4 S420M, EN 10025-4 S420 M, and S420M. These spacing variants refer to the same grade, not separate specifications. Use the complete designation and the contractual standard edition on the purchase order.
Key Advantages of EN 10025-4 S420M Steel Plate
- 420 MPa nominal yield class with clearly defined, thickness-dependent acceptance values through 120 mm for flat products in the 2004 tables.
- 40 J minimum longitudinal Charpy V-notch energy at −20 °C on full-size specimens under the normal verification arrangement for M quality.
- Fully killed fine-grain steel supplied in the thermomechanically rolled condition; the certified TM condition is not a normalized or quenched-and-tempered delivery.
- Carbon-equivalent limits in the material standard support weldability in heavily loaded welded structures when the actual heat analysis, thickness and procedure are considered.
- Plate processing can include bending, beveling, cutting of special-shaped parts and further work to agreed drawings, without a universal welding schedule being assumed.
Chemical Composition (Heat and Product Analysis)
| Element | Heat (ladle) analysis, mass % | Product analysis, mass % |
|---|---|---|
| C | 0.16 max | 0.18 max |
| Si | 0.50 max | 0.55 max |
| Mn | 1.70 max | 1.80 max |
| P | 0.030 max | 0.035 max |
| S | 0.025 max | 0.030 max |
| Nb | 0.05 max | 0.06 max |
| V | 0.12 max | 0.14 max |
| Al total | 0.02 min | 0.015 min |
| Ti | 0.05 max | 0.06 max |
| Cr | 0.30 max | 0.35 max |
| Ni | 0.80 max | 0.85 max |
| Mo | 0.20 max | 0.23 max |
| Cu | 0.55 max | 0.60 max |
| N | 0.025 max | 0.027 max |
Values are from EN 10025-4:2004, Table 2 (ladle / heat analysis) and Table 3 (product analysis), for the limits applicable to this grade. Aluminium is a minimum (total Al); the other individual entries are maxima. The minimum total aluminium content does not apply if sufficient other nitrogen-binding elements are present. Copper above the 2004 hot-shortness note (0.40 % heat, 0.45 % product) may cause hot shortness during hot forming. Long-product carbon and phosphorus/sulphur allowances in the same tables are not applied to plate on this page. These are specification limits, not typical heat analyses.
Mechanical Properties
| Nominal thickness | Minimum yield strength ReH, MPa | Tensile strength Rm, MPa | Minimum elongation A, % (L0 = 5.65 √S0) |
|---|---|---|---|
| ≤ 16 mm | 420 | 520–680 | 19 |
| > 16–40 mm | 400 | 520–680 | 19 |
| > 40–63 mm | 390 | 500–660 | 19 |
| > 63–80 mm | 380 | 480–640 | 19 |
| > 80–100 mm | 370 | 470–630 | 19 |
| > 100–120 mm | 365 | 460–620 | 19 |
Values are from EN 10025-4:2004, Table 5, for flat products up to 120 mm. For plate, strip and wide flats with width ≥ 600 mm the tensile test direction is transverse to the rolling direction; for other products it is longitudinal. For thickness < 3 mm, elongation on an 80 mm gauge length shall be agreed at enquiry and order. EN 10025-4 S420ML has the same tensile-property requirements at a given thickness and a different impact-quality specification.
Impact properties — Charpy V-notch, minimum energy in J. The normal verification, unless otherwise agreed, is longitudinal at −20 °C for M quality.
| Test temperature | M quality, longitudinal, J | ML quality, longitudinal, J | M quality, transverse, J (when agreed) | ML quality, transverse, J (when agreed) |
|---|---|---|---|---|
| +20 °C | 55 | 63 | 31 | 40 |
| 0 °C | 47 | 55 | 27 | 34 |
| −10 °C | 43 | 51 | 24 | 30 |
| −20 °C | 40 | 47 | 20 | 27 |
| −30 °C | — | 40 | — | 23 |
| −40 °C | — | 31 | — | 20 |
| −50 °C | — | 27 | — | 16 |
Values are from EN 10025-4:2004, Table 6 (longitudinal, the normal orientation) and Table 7 (transverse, only when agreed at order — option 30). An em dash means no value is specified for that quality at that temperature. For M quality, the 40 J minimum at −20 °C is the normal verification value; a 2004 footnote records that this corresponds with 27 J at −30 °C in Eurocode 3, which is not itself a Table 6 M-quality test requirement. For ML quality, the normal verification is 27 J at −50 °C. This page’s grade is M quality. Impact test pieces for plates ≥ 40 mm are taken from the ¼-thickness position (2004, 9.2.4). Average, individual and subsize acceptance, and any exemption for very thin flat products, follow the contractual edition. A test temperature is not by itself the allowable service temperature.
Delivery Condition and Fabrication
Products are supplied in the thermomechanically rolled condition. In EN 10025-4:2019+A1:2022 clause 3.1, thermomechanical rolling is the process in which the final deformation is carried out in a certain temperature range leading to a material condition with certain properties which cannot be achieved or repeated by heat treatment alone. It may include an increased cooling rate with or without tempering, including self-tempering, but excludes direct quenching and quenching and tempering. The steels shall be fully killed and have a fine-grain structure. Subsequent normalizing or quenching and tempering is not the specified delivery route and would not reproduce the certified TM condition. EN 10025-4:2004 clause 7.4.2.1 states that hot forming shall not be undertaken; TM-supplied products are not suitable for hot forming. The steels shall be suitable for welding; a qualified procedure must address actual chemistry, thickness, joint restraint and project rules, including the risk of cold cracking noted in the standard at higher thickness and strength.
Carbon Equivalent
| Nominal thickness | Maximum CEV, % (heat / ladle analysis) |
|---|---|
| ≤ 16 mm | 0.43 |
| > 16–40 mm | 0.45 |
| > 40–63 mm | 0.46 |
| > 63–120 mm | 0.47 |
Values are from EN 10025-4:2004, Table 4. The 2004 column for > 120–150 mm applies only to long products and is not stated as a plate figure here. The carbon equivalent is the IIW formula CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15, given in EN 10025-4:2019+A1:2022 clause 7.2.3 and referenced from EN 10025-1 in the 2004 edition. If silicon is controlled for hot-dip zinc coating, the standard provides a permitted CEV increase; use the contractual edition for that option.
Available Dimensions
Plate is supplied to dimensions agreed at enquiry — thickness, width and length — within the scope of the contractual edition of EN 10025-4. Tabulated mechanical values on this page cover flat products up to 120 mm (EN 10025-4:2004). The 2019 edition states a general thickness scope of ≤ 150 mm; values for the 120–150 mm flat-product band are not given here because the complete 2019 table set for that band was not independently obtained. No stock list, lead time or mill-inventory claim is stated. Dimensional tolerances follow the product standard named on the order (for plates, typically EN 10029 unless otherwise agreed).
Main Applications
EN 10025-4 is intended especially for heavily loaded parts of welded structures such as bridges, flood gates, storage tanks and water supply tanks, for service at ambient and low temperatures (2019+A1:2022 scope; the 2004 edition has the same intended-use wording in substance). EN 10025-4 S420M is selected when the project specifies this TM grade and M-quality toughness. Final suitability is a design-code and purchaser decision.
Equivalent Grades of EN 10025-4 S420M
| Standard / source | Grade or designation | Steel number | Remarks |
|---|---|---|---|
| EN 10025-4 S420ML | S420ML | 1.8836 | Same tensile table at a given thickness; different impact quality. Not an automatic substitute. |
| EN 10025-3 S420N | S420N | see EN 10025-3 page | Normalized or normalized-rolled counterpart in the same nominal yield class. Different delivery condition. Not a drop-in TM substitute. |
| EN 10025-3 S420NL | S420NL | see EN 10025-3 page | Normalized or normalized-rolled NL quality in the same nominal yield class. Different delivery condition. Not a drop-in TM substitute. |
| Former designation (EN 10113-3:1993 / former German designation) | Fe E 420 KG TM / StE420 TM | 1.8825 | Informative former names from EN 10025-4:2004 Annex A. Historical labels, not a separate current Gangsteel product URL. |
No direct cross-standard equivalent is asserted. A matching strength number does not establish substitution. Any alternate requires designer and purchaser approval after comparing chemistry, thickness-dependent strength, impact quality, delivery condition, fabrication rules and the applicable code edition.
Related Products
- EN 10025-4 steel plate — family page
- EN 10025-4 S275M steel plate
- EN 10025-4 S275ML steel plate
- EN 10025-4 S355M steel plate
- EN 10025-4 S355ML steel plate
- EN 10025-4 S420ML steel plate
- EN 10025-4 S460M steel plate
- EN 10025-4 S460ML steel plate
- EN 10025-3 steel plate — normalized / normalized-rolled family
- EN 10025-2 steel plate
- EN 10025-6 steel plate — quenched-and-tempered family
- Low-alloy and high-strength steel plate
Frequently Asked Questions (FAQ)
What is EN 10025-4 S420M (EN10025-4 S420M) steel plate?
It is a weldable fine-grain structural steel supplied in the thermomechanically rolled condition under EN 10025-4. The grade belongs to the 420 MPa nominal yield class and the M impact quality. Written forms such as EN10025-4 S420M, EN 10025-4 S420 M and S420M name the same designation. The complete thickness-dependent requirements matter more than the grade number alone.
Does EN 10025-4 S420M have the same yield strength at every thickness?
No. The minimum starts at 420 MPa for nominal thickness ≤ 16 mm and is 365 MPa at over 100–120 mm in the 2004 flat-product table. Tensile strength and elongation must also be checked against their own thickness bands. Values for a 120–150 mm flat-product band in the 2019 edition are not stated here.
What impact test applies to EN 10025-4 S420M?
The normal verification is longitudinal Charpy V-notch testing at −20 °C, with 40 J minimum on the Table 6 series (2004). ML quality, which is EN 10025-4 S420ML, uses 27 J at −50 °C instead. Transverse values apply only when agreed. Subsize specimens and thin products follow the contractual edition. A test temperature alone does not establish allowable service temperature.
Is EN 10025-4 S420M normalized or quenched and tempered?
No. The specified delivery is thermomechanically rolled. It is not a normalized or normalized-rolled EN 10025-3 steel and not a quenched-and-tempered EN 10025-6 steel. Hot forming shall not be undertaken on TM-supplied plate, because the certified TM properties cannot be achieved or repeated by heat treatment alone.
Can EN 10025-4 S420M 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 10025-4 S420M?
Only with approval. EN 10025-4 S420ML is a useful same-strength comparison with a different impact quality, not an unconditional equivalent. Normalized EN 10025-3 S420N / S420NL plates and, where linked above, EN 10025-2 or EN 10025-6 grades follow different delivery specifications. Check the full material specification, impact quality and design-code acceptance before changing the order.
What should an enquiry for EN 10025-4 S420M include?
Provide the standard edition, complete grade (EN 10025-4 S420M or EN10025-4 S420M), thickness × width × length, quantity, delivery condition (thermomechanically rolled), impact-test requirements, inspection documentation to EN 10204 as specified on the order, and any processing drawings. Availability, price and delivery are confirmed against that enquiry. No standing stock list is claimed on this page.
For production, processing and export enquiries for EN 10025-4 S420M steel plate, please contact Gangsteel. Visit Gangsteel for the full plate-supply range.