Steel P355NH
EN P355NH
P355NH is a normalized weldable fine-grain pressure vessel steel to EN 10028-3 (1.0565) with guaranteed elevated-temperature properties; equivalents include A516 Grade 70, SPV355 and Q345R.
Reference datasheet — P355NH 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 condition
P355NH tempers and conditions
P355NH is supplied in 6 conditions, soft to hard. +N is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+N | Heavy pressure-vessel plate; lower guaranteed strength and toughness, longer preheat/PWHT cycles. | 350 | 520 | 25 | 150 HB | 9 % IACS |
+N | Heavier plate class; specify Z-quality if through-thickness loading applies. | 370 | 535 | 26 | 155 HB | 9 % IACS |
Normalized then stress relieved / simulated PWHT | Ordered when the vessel receives post-weld heat treatment and the purchaser wants properties verified in the PWHT-simulated condition. | 375 | 530 | 29 | 152 HB | 9 % IACS |
+N | Same delivery condition, reduced guaranteed yield for medium plate thickness. | 380 | 540 | 27 | 158 HB | 9 % IACS |
+NDefault Normalized | Standard stocked delivery condition for EN 10028-3 pressure-vessel plate up to 16 mm; full 355 MPa yield class. | 390 | 545 | 28 | 160 HB | — |
Normalizing rolled | Mill-economic alternative to furnace normalizing with equivalent mechanical properties; choose when no further hot forming above ~580 °C is planned. | 400 | 550 | 27 | 163 HB | 9 % IACS |
Supply forms, finishes and certifications
Ways P355NH is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
+N Z35 | Normalized with EN 10164 through-thickness (Z-quality) requirement | Certification |
What is P355NH?
P355NH is a normalized weldable fine-grain pressure vessel steel to EN 10028-3 (1.0565) with guaranteed elevated-temperature properties; equivalents include A516 Grade 70, SPV355 and Q345R. It is used where vessels run hot, giving 390 MPa yield, 545 MPa tensile, 28 % elongation and about 160 HB (84 HRB), with plate conditions on file from 16 mm to 100 mm plus stress-relieved and Z35 through-thickness options. Maximum service temperature is about 400 °C; weldability rates 88/100 but heavy or restrained sections need preheat and code PWHT, and bare plate rusts without coating or overlay. P355NL1 is the choice when low-temperature toughness matters more. P355NH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). P355NH has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 64% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
What is P355NH used for?
- boiler components
- pressure vessels at elevated temperature
- piping flanges
- reactor shells
Advantages
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
P355NH properties
Typical room-temperature values for P355NH-+N; bars are the position among steel grades.
Physical3
P355NH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
P355NH has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 64% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P355NH is rated for continuous service to 400°C (752 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
P355NH conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of P355NH takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 22%.
Manufacturability7
P355NH's machinability is good (55/100, better than 62% 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. P355NH is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P355NH
Is P355NH easy to machine?
Machines like normalized 1020–1518 grade steel (~60 % of AISI 1212); use carbide inserts, moderate speeds and good chip control — long stringy chips on the softer heats.
Can P355NH be welded?
Excellent weldability by SAW/SMAW/GMAW with CEV ≈ 0.40–0.45; preheat 100–150 °C for thick or restrained sections, low-hydrogen consumables, PWHT at 550–620 °C per EN 13445/AD 2000.
Can P355NH be formed, bent or molded?
Cold-forms and rolls readily to vessel shells and dished heads (min bend radius ≈ 2t); hot forming above 580 °C requires re-normalizing to restore fine-grain properties.
P355NH 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 |
|---|---|---|
| C≤0.18 for t ≤ 30 mm in many mill practices | ≤ 0.2 | 0.16 |
| Si | ≤ 0.5 | 0.35 |
| Mn | 0.9 – 1.7 | 1.4 |
| P | ≤ 0.03 | 0.02 |
| S≤0.010 for Z-quality | ≤ 0.02 | 0.01 |
| Altotal Al, grain-refining element | ≥ 0.02 | 0.04 |
| N≤0.012 if no N-binding elements | ≤ 0.02 | 0.01 |
| Cr | ≤ 0.3 | 0.08 |
| Cu | ≤ 0.3 | 0.1 |
| Ni | ≤ 0.5 | 0.15 |
| Mo | ≤ 0.08 | 0.02 |
| NbNb+Ti+V ≤ 0.12 total | ≤ 0.05 | 0.02 |
| Ti | ≤ 0.03 | 0.01 |
| V | ≤ 0.1 | 0.02 |
| Fe | balance |
What surface finishes work on P355NH?
No anodizing; protect by shot-blasting plus epoxy/zinc-rich paint, hot-dip galvanizing, or stainless/Inconel weld-overlay cladding for corrosive process side.
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 P355NH in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.056510028-3
- Similar grades
- A516 Grade 70SPV355Q345R
How much does P355NH cost?
P355NH is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
P355NH — frequently asked
What is P355NH used for?
P355NH is typically used for boiler components, pressure vessels at elevated temperature, piping flanges and reactor shells. In short: guaranteed hot proof strength; normalized fine-grain vessel plate; Z35 through-thickness option.
What is the yield strength of P355NH?
P355NH has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is P355NH easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like normalized 1020–1518 grade steel (~60 % of AISI 1212); use carbide inserts, moderate speeds and good chip control — long stringy chips on the softer heats.
Can P355NH be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability by SAW/SMAW/GMAW with CEV ≈ 0.40–0.45; preheat 100–150 °C for thick or restrained sections, low-hydrogen consumables, PWHT at 550–620 °C per EN 13445/AD 2000.
What surface finishes work on P355NH?
No anodizing; protect by shot-blasting plus epoxy/zinc-rich paint, hot-dip galvanizing, or stainless/Inconel weld-overlay cladding for corrosive process side.
Can P355NH be formed, bent or molded?
Cold-forms and rolls readily to vessel shells and dished heads (min bend radius ≈ 2t); hot forming above 580 °C requires re-normalizing to restore fine-grain properties.
What is the maximum service temperature of P355NH?
P355NH is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does P355NH cost?
P355NH is a budget-cost steel ($), 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 10028-3 — Flat products made of steels for pressure purposes, Part 3: Weldable fine grain steels, normalized — CEN (2017)
- EN 10164 — Steel products with improved deformation properties perpendicular to the surface (Z-quality) — CEN (2018)
- ASTM A516/A516M — Pressure Vessel Plates, Carbon Steel, for Moderate and Lower-Temperature Service — ASTM (2021)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Pressure vessel plate P355NH data sheet — Dillinger / thyssenkrupp Steel (2022)
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.