Steel P355N N-thick
Heat-treated state
EN 1.0562, 10028-3
Thick-section plate for heavy-wall shells; the guaranteed yield falls stepwise with thickness per EN 10028-3.
Values for the N-thick condition
Other P355N tempers and conditions
P355N is listed in 6 conditions; see the grade overview at P355N.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
N-thickThis page N | Thick-section plate for heavy-wall shells; the guaranteed yield falls stepwise with thickness per EN 10028-3. | 330 | 520 | 25 | 155 HB | 9 % IACS |
normalized plus post-weld/stress-relief heat treatment (simulated) | Order when the fabricated vessel will see PWHT (≈550–620 °C) and the mill must certify properties after simulated heat treatment. | 370 | 525 | 27 | 152 HB | 9 % IACS |
NDefault Normalized | Standard normalized plate for ambient and moderately low temperature pressure vessels down to −20 °C. | 380 | 540 | 26 | 160 HB | 9 % IACS |
Normalized, guaranteed elevated-temperature properties | Pick when the vessel is designed above ~50 °C and a certified elevated-temperature proof strength (up to 400 °C) is required. | 385 | 545 | 24 | 162 HB | 9 % IACS |
Normalized, low-temperature toughness verified at −40 °C | Use for outdoor or refrigerated equipment where the minimum design metal temperature reaches −40 °C. | 385 | 545 | 25 | 160 HB | 9 % IACS |
Normalized, low-temperature toughness verified at −50 °C | Cleanest variant (lower P and S) for cryogenic-leaning service and thick sections needing the best notch toughness. | 390 | 545 | 26 | 160 HB | 9 % IACS |
What is P355N N-thick?
P355N N-thick is P355N heat treated to N-thick — thick-section plate for heavy-wall shells; the guaranteed yield falls stepwise with thickness per EN 10028-3. P355N N-thick has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 78% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi). P355N N-thick has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). N is the default condition FabDigit quotes; N-thick is available on request or by drawing note.
Advantages
- Readily welded — 85/100, better than 83% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Forms and bends easily — 62/100, better than 78% 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
- Low strength — 330 MPa (47.9 ksi), worse than 78% of steel grades
P355N N-thick properties
Typical room-temperature values for P355N N-thick; 22 are specific to this condition. Other listed values are P355N reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
P355N N-thick has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
P355N N-thick has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 78% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P355N N-thick is rated for continuous service to 400°C (752 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
P355N N-thick conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of P355N N-thick takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
P355N N-thick's machinability is good (58/100, better than 75% of steel grades); weldability excellent (85/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with P355N N-thick
Is P355N easy to machine?
Machines like ordinary C-Mn plate at ~60 % of AISI 1212; use rigid setups and coolant on drilled nozzle holes, watch for stringy chips at low hardness.
Can P355N be welded?
Excellent weldability with CEV typically ≤0.43; SAW/SMAW/GMAW with low-hydrogen consumables, preheat 100–150 °C for thick sections and PWHT 550–620 °C when required by code.
Can P355N be formed, bent or molded?
Cold-forms readily into heads and shells (min bend radius ~1.5–2 t); hot forming 900–1000 °C must be followed by re-normalizing to restore fine grain and toughness.
What surface finishes work on P355N?
No anodizing — shot blast to Sa 2.5 then epoxy/zinc-rich paint, metallize or hot-dip galvanize; internal service usually lined or corrosion-allowance based.
P355N 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 for t ≤ 150 mm | ≤ 0.2 | 0.17 |
| Si | ≤ 0.5 | 0.35 |
| Mn | 1.1 – 1.7 | 1.4 |
| P≤0.025 for NL1, ≤0.020 for NL2 | ≤ 0.03 | 0.02 |
| S≤0.015 for NL1, ≤0.010 for NL2 | ≤ 0.03 | 0.01 |
| Altotal Al, grain refinement | ≥ 0.02 | 0.03 |
| Cr | ≤ 0.3 | 0.08 |
| Cu | ≤ 0.3 | 0.1 |
| Mo | ≤ 0.08 | 0.02 |
| Ni | ≤ 0.5 | 0.1 |
| NbNb+Ti+V ≤ 0.12 | ≤ 0.05 | 0.02 |
| Ti | ≤ 0.03 | 0.01 |
| V | ≤ 0.1 | 0.02 |
| Nlower for NL2 | ≤ 0.02 | 0.01 |
| Fe | balance | — |
P355N N-thick — frequently asked
What is P355N N-thick used for?
P355N N-thick is typically used for boiler drums, pressure vessel shells, storage tanks and heat exchangers. In short: baseline normalized vessel plate; good toughness, easy welding; 400 °C service ceiling.
What is the yield strength of P355N N-thick?
P355N N-thick has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is P355N N-thick easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like ordinary C-Mn plate at ~60 % of AISI 1212; use rigid setups and coolant on drilled nozzle holes, watch for stringy chips at low hardness.
Can P355N N-thick be welded?
Yes — weldability is rated excellent (85/100). Excellent weldability with CEV typically ≤0.43; SAW/SMAW/GMAW with low-hydrogen consumables, preheat 100–150 °C for thick sections and PWHT 550–620 °C when required by code.
What surface finishes work on P355N N-thick?
No anodizing — shot blast to Sa 2.5 then epoxy/zinc-rich paint, metallize or hot-dip galvanize; internal service usually lined or corrosion-allowance based.
Can P355N N-thick be formed, bent or molded?
Cold-forms readily into heads and shells (min bend radius ~1.5–2 t); hot forming 900–1000 °C must be followed by re-normalizing to restore fine grain and toughness.
What is the maximum service temperature of P355N N-thick?
P355N N-thick 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 P355N-N and P355N N-thick?
N is the default condition — standard normalized plate for ambient and moderately low temperature pressure vessels down to −20 °C. N-thick: thick-section plate for heavy-wall shells; the guaranteed yield falls stepwise with thickness per EN 10028-3. Yield strength is 380 MPa in N versus 330 MPa in N-thick.
Sources
- EN 10028-3: Flat products made of steels for pressure purposes — Weldable fine grain steels, normalized — CEN (2017)
- EN 10027-1/-2 designation and material number 1.0562 — CEN (2016)
- GB/T 713 Q345R steel plates for boilers and pressure vessels — SAC (2014)
- ASTM A516/A516M Grade 70 pressure vessel plate — ASTM (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- EN 13445-2/-3/-4 Unfired pressure vessels — CEN (2021)
- Mysteel / SMM — Mysteel / SMM (2025)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.