Steel S355N
EN S355N · GB Q355N
Normalized, weldable fine-grain structural steel per EN 10025-3 providing improved toughness and weldability over standard S355, common in heavy welded structures and pressure-related steel components.
Reference datasheet — S355N is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +N t<=16 condition
S355N tempers and conditions
S355N is supplied in 8 conditions, soft to hard. +N t<=16 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+N | Very heavy normalized plate/forged bar; yield 295 MPa (100–150 mm) / 285 MPa (150–200 mm) with reduced tensile band. | 310 | 480 | 22 | 145 HB | 10.8 % IACS |
+N | Thick-section plate where through-thickness toughness matters; yield 325 MPa (63–80 mm) / 315 MPa (80–100 mm). | 340 | 500 | 23 | 147 HB | 10.8 % IACS |
+N | Heavy plate for base plates and thick welded nodes; yield 335 MPa minimum. | 360 | 520 | 24 | 150 HB | 10.8 % IACS |
+N + stress relieved | Use for thick welded pressure-related fabrications requiring PWHT; slight softening but residual stresses and distortion greatly reduced. | 365 | 520 | 26 | 150 HB | 10.8 % IACS |
+N | Medium plate for welded girders and machine frames; yield down-rated to 345 MPa per EN 10025-3. | 370 | 530 | 24 | 152 HB | 10.8 % IACS |
+N t<=16Default +N | Standard stocked condition for plate, section and bar up to 16 mm; full 355 MPa yield with 40 J at −20 °C. | 380 | 540 | 25 | 155 HB | 10.8 % IACS |
S355NL | Choose when service or hydrotest temperature goes below −20 °C (offshore, cold-climate cranes, LPG structures); tighter P/S limits. | 380 | 540 | 25 | 155 HB | 10.8 % IACS |
Cold drawn | For close-tolerance bar and shafts; cold work raises yield and hardness but cuts elongation and adds residual stress. | 470 | 590 | 14 | 11 HRC | 10.5 % IACS |
What is S355N?
Normalized, weldable fine-grain structural steel per EN 10025-3 providing improved toughness and weldability over standard S355, common in heavy welded structures and pressure-related steel components. S355N has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). S355N has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 68% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
What is S355N used for?
- bridges
- offshore structures
- pressure-related steel fabrications
- heavy welded frames
- penstocks
Advantages
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S355N properties
Typical room-temperature values for S355N-+N t<=16; bars are the position among steel grades.
Physical3
S355N has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
S355N has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 68% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S355N is rated for continuous service to 400°C (752 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
S355N conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S355N takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
S355N's machinability is good (58/100, better than 75% of steel grades); weldability excellent (88/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. S355N is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S355N
Is S355N easy to machine?
Machines like a normalized C-Mn steel at ~60 % of AISI 1212; use rigid setups, coolant and coated carbide, and expect stringy chips at low sulphur levels.
Can S355N be welded?
Excellent weldability by SMAW/GMAW/SAW with matched low-hydrogen consumables; CEV ≤ 0.43 means little or no preheat below ~30 mm, preheat 100–150 °C for heavy sections, keep heat input moderate to protect fine-grain HAZ toughness.
Can S355N be formed, bent or molded?
Good cold bending (typical minimum bend radius 1.5–2.5 t depending on thickness and orientation); hot forming above 900 °C should be followed by re-normalizing at 890–940 °C to restore properties.
S355N chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cmax 0.20 % for t ≤ 250 mm | ≤ 0.2 | 0.17 |
| Si | ≤ 0.5 | 0.35 |
| Mn | 0.9 – 1.65 | 1.4 |
| P0.025 max for S355NL | ≤ 0.03 | 0.02 |
| S0.020 max for S355NL | ≤ 0.03 | 0.01 |
| Nlimit may be exceeded if sufficient N-binding elements present | ≤ 0.02 | 0.01 |
| Altotal Al, min for grain refinement | ≥ 0.02 | 0.03 |
| NbNb+Ti+V ≤ 0.22 % | ≤ 0.05 | 0.03 |
| V | ≤ 0.12 | 0.04 |
| Ti | ≤ 0.05 | 0.02 |
| Cr | ≤ 0.3 | 0.1 |
| Ni | ≤ 0.5 | 0.1 |
| Mo | ≤ 0.1 | 0.02 |
| Cu | ≤ 0.35 | 0.15 |
| FeCEV ≤ 0.43 for t ≤ 63 mm | balance |
What surface finishes work on S355N?
No natural corrosion resistance — shot blast to Sa 2½ then zinc-rich primer/epoxy per ISO 12944, or hot-dip galvanize (Si content controls coating thickness); not anodizable.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel S355N in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.0545
- GB (China)
- Q355N
- Similar grades
- A633 Grade A
How much does S355N cost?
S355N is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S355N — frequently asked
What is S355N used for?
S355N is typically used for bridges, offshore structures, pressure-related steel fabrications, heavy welded frames and penstocks. In short: normalized fine-grain S355; weldable at CEV ≤ 0.43; tougher than plain S355.
What is the yield strength of S355N?
S355N has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is S355N easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a normalized C-Mn steel at ~60 % of AISI 1212; use rigid setups, coolant and coated carbide, and expect stringy chips at low sulphur levels.
Can S355N be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability by SMAW/GMAW/SAW with matched low-hydrogen consumables; CEV ≤ 0.43 means little or no preheat below ~30 mm, preheat 100–150 °C for heavy sections, keep heat input moderate to protect fine-grain HAZ toughness.
What surface finishes work on S355N?
No natural corrosion resistance — shot blast to Sa 2½ then zinc-rich primer/epoxy per ISO 12944, or hot-dip galvanize (Si content controls coating thickness); not anodizable.
Can S355N be formed, bent or molded?
Good cold bending (typical minimum bend radius 1.5–2.5 t depending on thickness and orientation); hot forming above 900 °C should be followed by re-normalizing at 890–940 °C to restore properties.
What is the maximum service temperature of S355N?
S355N is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S355N +N t<=16 and S355N-CD?
+N t<=16 is the default condition — standard stocked condition for plate, section and bar up to 16 mm; full 355 MPa yield with 40 J at −20 °C. CD: for close-tolerance bar and shafts; cold work raises yield and hardness but cuts elongation and adds residual stress. Yield strength is 380 MPa in +N t<=16 versus 470 MPa in CD.
How much does S355N cost?
S355N is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- EN 10025-3 Hot rolled products of structural steels — Normalized/normalized rolled weldable fine grain steels — CEN (2019)
- EN 10027-2 / 1.0545 material number designation — CEN (2015)
- ASTM A633/A633M Normalized High-Strength Low-Alloy Structural Steel Plates — ASTM (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- EN 1993-1-1 / EN 1993-1-2 Eurocode 3 design and thermal properties of structural steel — CEN (2005)
- Normalized fine-grain structural steel plate datasheets (S355N/NL) — European plate mills (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.