What is EN 10025-3 S420NL Steel?
EN 10025-3 S420NL steel plate is a high-strength, fine-grained structural steel designed for weldable applications in low-temperature environments. It complies with the European standard EN 10025-3, which specifies technical delivery conditions for normalized/normalized rolled weldable fine grain structural steels. The typical delivery condition is normalized or normalized rolled, ensuring a refined microstructure for enhanced toughness and resistance to brittle fracture.
The grade "EN 10025-3 S420NL" is defined as:
S: Structural steel.
420: Minimum yield strength of 420 MPa for thicknesses up to 16 mm.
NL: Normalized with impact testing at -50°C for superior low-temperature performance.
Classified as a fine grain structural steel, EN 10025-3 S420NL features controlled grain size, offering excellent weldability, ductility, and impact resistance, making it ideal for demanding structures in cold climates.
Discover our full range of EN 10025-3 normalized steel plates for various structural applications.
What is the Chemical Composition of EN 10025-3 S420NL Steel?
The chemical composition of EN 10025-3 S420NL is optimized to balance strength, toughness, and weldability, with low carbon and alloying elements to minimize welding challenges.
The table below shows the ladle analysis (melt stage) and product analysis (finished plate) per EN 10025-3:
|
Element |
Ladle Analysis (max %) |
Product Analysis (max %) |
|---|---|---|
|
Carbon (C) |
0.20 |
0.22 |
|
Silicon (Si) |
0.60 |
0.65 |
|
Manganese (Mn) |
1.00-1.70 |
0.95-1.80 |
|
Phosphorus (P) |
0.025 |
0.030 |
|
Sulfur (S) |
0.020 |
0.025 |
|
Nitrogen (N) |
0.025 |
0.027 |
|
Aluminum (Al) |
0.020 (min, total) |
0.015 (min, total) |
|
Niobium (Nb) |
0.05 |
0.06 |
|
Vanadium (V) |
0.20 |
0.22 |
|
Titanium (Ti) |
0.05 |
0.06 |
|
Chromium (Cr) |
0.30 |
0.35 |
|
Nickel (Ni) |
0.80 |
0.85 |
|
Molybdenum (Mo) |
0.10 |
0.12 |
|
Copper (Cu) |
0.55 |
0.60 |
The Carbon Equivalent (CEV) is calculated as: CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15. For EN 10025-3 S420NL, CEV is ≤0.43% (up to 63 mm thickness), ensuring excellent weldability with low risk of cold cracking, suitable for standard fabrication processes.
Mechanical Properties of EN 10025-3 S420NL
EN 10025-3 S420NL delivers high strength and toughness, with a minimum yield strength of ≥420 MPa, tensile strength of 520-680 MPa, and elongation ≥19%. It provides robust impact toughness of ≥27 J at -50°C (Charpy V-notch, longitudinal), making it suitable for sub-zero conditions.
Properties vary with thickness; refer to the table:
|
Thickness (mm) |
Yield Strength (min, MPa) |
Tensile Strength (MPa) |
Elongation (min, %) |
Impact Energy (min, J @ -50°C, Longitudinal) |
|---|---|---|---|---|
|
≤16 |
420 |
520-680 |
19 |
27 |
|
16<t≤40 |
400 |
520-680 |
19 |
27 |
|
40<t≤63 |
390 |
520-680 |
19 |
27 |
|
63<t≤80 |
380 |
520-680 |
19 |
27 |
|
80<t≤100 |
360 |
520-680 |
19 |
27 |
|
100<t≤150 |
340 |
500-650 |
19 |
27 |
|
150<t≤200 |
330 |
500-650 |
19 |
27 |
These properties make EN 10025-3 S420NL ideal for high-stress, cold-environment structures.
What is the Equivalent Grade of EN 10025-3 S420NL?
EN 10025-3 S420NL aligns with several international standards, with minor variations:
|
Standard |
Equivalent Steel Grade |
|---|---|
|
EN (Thermo-mechanical) |
S420ML |
|
EN normalized |
S420N |
|
DIN |
StE 420 / TStE 420 |
|
AFNOR (France) |
E 420 FP |
|
BS (UK) |
50 EE |
|
UNI (Italy) |
Fe E 420 KTN |
|
GB (China) |
Q420E |
|
ASTM / ASME |
A572 Grade 60 (approximate) |
For the -20°C variant, see EN 10025-3 S420N normalized structural steel plate.
What is the Difference Between EN 10025-3 S420NL and S420N / S420ML / S355NL?
Key differences guide material selection:
EN 10025-3 S420NL vs S420N: Both have 420 MPa yield, but S420NL ensures impact toughness at -50°C (vs -20°C for S420N), suiting colder environments like arctic infrastructure. Explore EN 10025-3 S420N normalized structural steel plate.
EN 10025-3 S420NL vs S420ML: S420ML employs thermomechanical controlled processing (TMCP) for finer grains and cost-effective welding, while S420NL's normalization offers consistent low-temperature performance.
EN 10025-3 S420NL vs S355NL: S420NL provides higher yield (420 MPa vs 355 MPa) for stronger, lighter designs at a higher cost; S355NL is more economical for moderate loads. Check EN 10025-3 S355NL normalized structural steel plate.
These factors affect performance, cost, and environmental suitability.