S460NL
1.8903
High-strength weldable fine-grain structural steel; alloy special steel · EN 10025-3:2019
S460NL is the low-temperature-toughness quality of the EN 10025-3 normalized or normalized-rolled S460 fine-grain structural steel. It combines a minimum yield strength of 460 MPa at thicknesses up to 16 mm with specified longitudinal Charpy V-notch energy of 27 J at −50 °C. Strength decreases with thickness, and the NL designation is a material toughness classification—not an unconditional −50 °C service rating.
- 1.8903Material number · Alternative numerical designation under EN 10027-2.
- 460 MPa minimum at t ≤ 16 mmYield strength · Falls progressively to 370 MPa for thicknesses above 150 mm.
- 27 J minimum at −50 °CLow-temperature toughness · Longitudinal Charpy V-notch specimens; average requirement under the standard test rules.
- Normalized or normalized rolledDelivery condition · This condition is fundamental to the EN 10025-3 grade definition.
- 0.53–0.55%Maximum CEV · Thickness-dependent maximum based on heat analysis.
- Hot-rolled flat and long products through 250 mmStandard scope · Actual mill availability can be narrower and must be confirmed.
Overview
- Designation system
- EN 10027 steel name and numerical designation systems
- Product forms
- Hot-rolled plate, sheet and strip, Wide flats, Hot-rolled sections, Bars and rod
- Condition
- Normalized, Normalized rolled, Delayed cooling or additional tempering may follow normalizing or normalizing rolling and must be reported in the—and is, Delayed cooling or additional tempering may follow normalizing or normalizing rolling and must be reported in the—
What the designation means
The complete designation is EN 10025-3 — S460NL or EN 10025-3 — 1.8903. “S” identifies structural steel; “460” is the minimum specified room-temperature yield strength in MPa for nominal thickness up to 16 mm; “N” identifies normalized or normalized-rolled delivery; and “L” identifies the quality having specified impact properties down to −50 °C.
EN 10025-3 covers hot-rolled flat and long products of weldable fine-grain structural steel. S460 is classified under EN 10020 as an alloy special steel. Products are fully killed, have a controlled fine-grain structure, and contain sufficient nitrogen-binding elements. The standard defines fine-grain steel by an equivalent ferritic grain-size index of at least 6.
Do not read “NL” as a universal permissible service temperature. Structural detail, stress level, section thickness, strain rate, weld condition, flaw population and the applicable fracture-toughness rules must also be considered.
Delivery condition and dimensional scope
Products must be supplied normalized or in an equivalent condition produced by normalizing rolling. Because S460 has a minimum yield strength of at least 420 MPa, the producer may use delayed cooling or additional tempering after normalizing or normalizing rolling; any such treatment must be stated in the inspection document.
| Category | Examples and applicability |
|---|---|
| Flat products | Plate, sheet, strip and wide flats |
| Long products | Sections, bars and rod |
| Standard thickness scope | Nominal thickness through 250 mm |
| Practical availability | Depends on product form, dimensions and producer qualification; the standard's scope does not guarantee commercial availability in every size |
Chemical composition and weldability controls
| Element | Requirement, mass % |
|---|---|
| C | ≤ 0.20 |
| Si | ≤ 0.60 |
| Mn | 1.00–1.70 |
| P | ≤ 0.025 |
| S | ≤ 0.020 |
| Nb | ≤ 0.050 |
| V | ≤ 0.20 |
| Total Al | ≥ 0.020 |
| Ti | ≤ 0.050 |
| Cr | ≤ 0.30 |
| Ni | ≤ 0.80 |
| Mo | ≤ 0.10 |
| Cu | ≤ 0.55 |
| N | ≤ 0.025 |
| V + Nb + Ti | ≤ 0.22 |
| Mo + Cr | ≤ 0.30 |
The minimum total-aluminium requirement does not apply when sufficient other nitrogen-binding elements are present. For long products, the permitted P and S maxima may each be 0.005 percentage point higher. Product-analysis limits differ from heat-analysis limits and apply only when product analysis is ordered.
| Nominal thickness t | Maximum CEV |
|---|---|
| t ≤ 63 mm | 0.53% |
| 63 < t ≤ 100 mm | 0.54% |
| 100 < t ≤ 250 mm | 0.55% |
Special chemistry agreed for hot-dip galvanizing can permit the standard CEV limit to be increased by 0.01 or 0.02 percentage point, depending on the silicon restriction.
S460NL is specified as weldable, but its relatively high permitted CEV and strength level make weldability strongly dependent on thickness, actual chemistry, hydrogen level, heat input, joint restraint and temperature. Welding should follow EN 1011-2 and an appropriately qualified welding procedure. Low-hydrogen consumables and handling, suitable preheat and interpass control, and control of heat input are particularly important for thick or highly restrained joints. Filler-metal selection must address the required joint strength and weld-metal and heat-affected-zone toughness at the project design temperature.
Thickness-dependent tensile properties
| Nominal thickness t | Minimum ReH or Rp0.2 | Tensile strength Rm | Minimum elongation A |
|---|---|---|---|
| t ≤ 16 mm | 460 MPa | 540–720 MPa | 17% |
| 16 < t ≤ 40 mm | 440 MPa | 540–720 MPa | 17% |
| 40 < t ≤ 63 mm | 430 MPa | 540–720 MPa | 17% |
| 63 < t ≤ 80 mm | 410 MPa | 540–720 MPa | 17% |
| 80 < t ≤ 100 mm | 400 MPa | 540–720 MPa | 17% |
| 100 < t ≤ 150 mm | 380 MPa | 530–710 MPa | 17% |
| 150 < t ≤ 200 mm | 370 MPa | 530–710 MPa | 17% |
| 200 < t ≤ 250 mm | 370 MPa | 510–690 MPa | 16% |
Elongation is measured using proportional gauge length L0 = 5.65√S0. For plate, strip and wide flats at least 600 mm wide, tensile requirements apply to transverse specimens; for other products they apply parallel to the rolling direction.
A purchase order, design calculation or substitution review must use the specified strength for the actual governing thickness. Calling all S460NL material “460 MPa steel” is incorrect for thicknesses above 16 mm.
Charpy impact toughness
| Test temperature (J) | +20 | 0 | −10 | −20 | −30 | −40 | −50 |
|---|---|---|---|---|---|---|---|
| Minimum longitudinal Charpy V-notch energy | 63 | 55 | 51 | 47 | 40 | 31 | 27 |
NL quality is normally verified at −50 °C. The listed values are minimum average energies for longitudinal specimens.
| Test temperature (J) | +20 | 0 | −10 | −20 | −30 | −40 | −50 |
|---|---|---|---|---|---|---|---|
| Minimum transverse Charpy V-notch energy when Option 30 is ordered | 40 | 34 | 30 | 27 | 23 | 20 | 16 |
Transverse impact testing is not the basic requirement; it must be agreed at ordering.
The normal impact test uses three EN ISO 148-1 V-notch specimens with a 2 mm striker. The average must meet the specified value; one result may be below it but not below 70% of the requirement. Reduced-width specimens are used where product dimensions do not allow full-size specimens, with requirements reduced in proportion to specimen cross-sectional area. Impact testing is generally not required for flat products or sections below 6 mm thickness, and dimensional restrictions also apply to small bars and rod.
Sampling position matters for heavy plate: at nominal thickness of 40 mm or more, plate impact specimens are taken at the quarter-thickness position. Test certificates should therefore be reviewed for specimen orientation, sampling position, test temperature and specimen size—not only the reported joule value.
Forming, heat treatment and galvanizing
Hot forming can be used, but the finished product must retain the specified tensile and impact properties. Guidance for hot forming, cold forming and flame straightening is given in CEN/TR 10347. Cold work reduces ductility, so severe forming, forming at low temperature and galvanizing after cold deformation require engineering review.
| Operation | Applicability when specifically ordered | Minimum inside bend radius for S460 |
|---|---|---|
| Flanging without cracking | Plate, sheet, strip and wide flats; t ≤ 16 mm; EN 10025-3 Option 11 | 4t with bend axis transverse to rolling direction; 5t with bend axis longitudinal to rolling direction |
| Roll forming | Plate, sheet and strip; t ≤ 8 mm; EN 10025-3 Option 12 | Same radii as the flanging option |
These capabilities are not automatically included in a basic S460NL order.
Stress relieving above 580 °C or for more than one hour can deteriorate mechanical properties. For flat products, EN 10025-3 recommends a maximum stress-relief temperature of 560 °C. If higher temperatures or longer holding times are intended, the required post-treatment properties should be agreed with the steelmaker when ordering.
If hot-dip galvanizing is intended, specify it at enquiry and order. EN 10025-3 Option 5 permits agreement of silicon and phosphorus ranges suited to coating formation. Galvanizing requirements are specified through EN ISO 1461, with composition and coating guidance in EN ISO 14713-2. The interaction between prior cold work, residual stress and galvanizing must also be considered because of the risk of brittle cracking.
Ordering and inspection points
A technically complete order identifies the quantity, product form, dimensional and tolerance standard, nominal dimensions, full grade designation EN 10025-3 — S460NL or 1.8903, required inspection document under EN 10204, and every applicable option. The standard requires specific inspection and testing, including heat analysis, tensile testing and impact testing subject to dimensional limitations.
| Requirement | Ordering action |
|---|---|
| Product analysis | Invoke Option 2 and define the required frequency if not once per cast |
| Through-thickness ductility | Specify the required EN 10164 Z-quality through Option 4 where lamellar-tearing resistance is needed |
| Internal soundness | Specify ultrasonic testing and the acceptance class; UT is not automatic |
| Galvanizing chemistry | Invoke Option 5 and agree the Si/P composition category |
| Cold forming | Invoke Option 11 for flanging or Option 12 for roll forming, within the stated dimensional limits |
| Parent plate or coil testing | Use Option 13 for impact testing or Option 14 for impact and tensile testing from each parent plate or coil |
| Impact test temperature | Specify another listed temperature using Option 24 when required |
| Transverse impact properties | Invoke Option 30 |
| Surface quality | State any class differing from the standard defaults |
| Marking restrictions | Specify special marking or restrictions on die stamping where fatigue or surface integrity is important |
For plates and wide flats, the basic surface requirement is EN 10163-2 class A, subclass 1. For sections it is EN 10163-3 class C, subclass 1. Ultrasonic examination is an optional requirement: when ordered, flat products of at least 6 mm thickness are tested to EN 10160, relevant beams to EN 10306, and bars to EN 10308.
Review the inspection certificate for the exact product form and thickness range, delivery condition, any delayed cooling or tempering, heat chemistry and CEV, tensile-test orientation, Charpy orientation and temperature, specimen size, and all project-specific options.
Selection and substitution boundaries
S460NL is intended for heavily loaded welded structures operating at ambient and low temperatures, including applications such as bridges, hydraulic structures and storage or water tanks. Suitability for a particular structure still depends on the applicable design, fabrication, execution, fatigue, fracture and corrosion-protection standards.
Substitution by another nominal S460 grade requires more than matching yield strength. The product standard, delivery route, thickness-dependent strength, Charpy orientation and temperature, CEV, available dimensions, heat-treatment response, testing frequency, dimensional tolerances and certification must all be compared. Thermomechanically rolled S460ML and quenched-and-tempered S460QL are different standardized materials, even when their nominal strength or low-temperature impact class appears similar.
Sources
- BS EN 10025-3:2019 — Hot rolled products of structural steels: Technical delivery conditions for normalized/normalized rolled weldable fine grain structural steelsBritish Standards Institution
- EN 10025-3:2019 standard previewSlovenian Institute for Standardization / iTeh Standards
- BS EN 10025-3:2019 — Structural steel delivery conditionsStudyLib
- Declaration of Performance — S460NL / 1.8903 according to EN 10025-3:2019Marcegaglia
Ask MetalMate about S460NL
Discussing: S460NL / 1.8903
AI assistant · Responses are generated and can contain errors; verify specifications before acting.