Steel P355M
EN 1.8821, 10028-5
P355M is a thermomechanically rolled fine-grain pressure vessel steel to EN 10028-5 (1.8821) in the 355 MPa minimum yield class, showing 385 MPa yield, 520 MPa tensile, 26 % elongation and 155 HB in the default M condition.
Reference datasheet — P355M 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 M condition
P355M tempers and conditions
P355M is supplied in 7 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M | Maximum standard thickness range; check mill capability, through-thickness properties often ordered with Z-quality. | 345 | 495 | 25 | 148 HB | 9 % IACS |
M | Heavy plate for thick-wall shells; slightly lower guaranteed yield and toughness scatter. | 365 | 505 | 25 | 150 HB | 9 % IACS |
thermomechanically rolled and post-weld stress relieved (~530–580 °C) | Use for thick-wall or code-mandated PWHT vessels; expect a small drop in yield and hardness after long soaks. | 370 | 505 | 27 | 148 HB | 9 % IACS |
M | Mid-thickness plate; yield drops one step per EN 10028-5 thickness table. | 375 | 515 | 26 | 152 HB | 9 % IACS |
MDefault Thermomechanically controlled processed | Standard as-delivered TMCP plate for ambient/moderate-temperature welded vessels; impact tested at 0 °C. | 385 | 520 | 26 | 155 HB | 9 % IACS |
TMCP, low-temperature quality | Pick when the vessel design temperature reaches −20 °C; tighter P/S limits than P355M. | 385 | 520 | 27 | 155 HB | 9 % IACS |
TMCP, extra-low-temperature quality | Cryogenic-leaning option for LPG/ammonia and cold-climate tanks; lowest S/P and best CVN. | 390 | 525 | 28 | 156 HB | 9 % IACS |
What is P355M?
P355M is a thermomechanically rolled fine-grain pressure vessel steel to EN 10028-5 (1.8821) in the 355 MPa minimum yield class, showing 385 MPa yield, 520 MPa tensile, 26 % elongation and 155 HB in the default M condition. Fabricators choose it for welded tanks and vessels because the low carbon equivalent simplifies welding; plate is supplied in thickness bands to 100 mm, plus ML1/ML2 low-temperature and M+SR stress-relieved variants. Maximum service temperature is 400 °C, the steel has no corrosion resistance, and heating above about 580 °C destroys the TMCP condition. P420M is the next strength step when wall thickness must be reduced. P355M has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). P355M has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 65% of steel grades. Elongation at break is 26% and the elastic modulus is 210 GPa (30.5 Msi).
What is P355M used for?
- pressure vessels
- boilers
- storage tanks
- piping
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Readily welded — 90/100, better than 90% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Forms and bends easily — 72/100, better than 88% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
P355M properties
Typical room-temperature values for P355M-M; bars are the position among steel grades.
Physical3
P355M has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical16
P355M has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 65% of steel grades. Elongation at break is 26% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P355M 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
P355M 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 P355M takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
P355M's machinability is good (58/100, better than 75% of steel grades); weldability excellent (90/100); formability very good (72/100).
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. P355M is highlighted; hover a dot for its name, or open the interactive family chart.
Working with P355M
Is P355M easy to machine?
Machines like HSLA plate — moderate cutting speeds, positive-rake sharp carbide and good chip control; microalloy carbonitrides cause some abrasion and stringy chips.
Can P355M be welded?
Excellent weldability due to low carbon equivalent — SAW/GMAW/SMAW with matching 355-class consumables, low hydrogen, controlled heat input to avoid HAZ softening of the TMCP structure; preheat usually only for heavy sections.
Can P355M be formed, bent or molded?
Good cold formability (press-braking, rolling of shells); avoid hot forming above ~580 °C or re-normalizing, since that destroys the thermomechanical strengthening — re-qualify properties if done.
P355M 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 |
|---|---|---|
| Cladle analysis, EN 10028-5 | ≤ 0.16 | 0.12 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 1 – 1.7 | 1.4 |
| PML1 ≤0.025, ML2 ≤0.020 | ≤ 0.03 | 0.02 |
| SML1 ≤0.015, ML2 ≤0.010 | ≤ 0.03 | 0.01 |
| Altotal Al; other grain-refining practice permitted | ≥ 0.02 | 0.04 |
| Cr | ≤ 0.3 | 0.05 |
| Ni | ≤ 0.5 | 0.1 |
| Cu | ≤ 0.7 | 0.1 |
| Mo | ≤ 0.1 | 0.02 |
| Nbmicroalloy; Nb+Ti+V ≤ 0.12 total | ≤ 0.05 | 0.03 |
| Ti | ≤ 0.05 | 0.02 |
| V | ≤ 0.1 | 0.03 |
| N | ≤ 0.02 | 0.01 |
| Fe | balance |
What surface finishes work on P355M?
No inherent corrosion resistance: blast to Sa 2½ and apply epoxy/zinc-rich primer systems, hot-dip galvanizing or internal lining; readily paintable and weld-seam ground for NDT.
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 P355M in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.882110028-5
How much does P355M cost?
P355M 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.
P355M — frequently asked
What is P355M used for?
P355M is typically used for pressure vessels, boilers, storage tanks and piping. In short: workhorse TMCP vessel plate; low CEV, easy welding; 400 °C service ceiling.
What is the yield strength of P355M?
P355M has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is P355M easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like HSLA plate — moderate cutting speeds, positive-rake sharp carbide and good chip control; microalloy carbonitrides cause some abrasion and stringy chips.
Can P355M be welded?
Yes — weldability is rated excellent (90/100). Excellent weldability due to low carbon equivalent — SAW/GMAW/SMAW with matching 355-class consumables, low hydrogen, controlled heat input to avoid HAZ softening of the TMCP structure; preheat usually only for heavy sections.
What surface finishes work on P355M?
No inherent corrosion resistance: blast to Sa 2½ and apply epoxy/zinc-rich primer systems, hot-dip galvanizing or internal lining; readily paintable and weld-seam ground for NDT.
Can P355M be formed, bent or molded?
Good cold formability (press-braking, rolling of shells); avoid hot forming above ~580 °C or re-normalizing, since that destroys the thermomechanical strengthening — re-qualify properties if done.
What is the maximum service temperature of P355M?
P355M 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 P355M-M and P355M-ML2?
M is the default condition — standard as-delivered TMCP plate for ambient/moderate-temperature welded vessels; impact tested at 0 °C. ML2: cryogenic-leaning option for LPG/ammonia and cold-climate tanks; lowest S/P and best CVN. Yield strength is 385 MPa in M versus 390 MPa in ML2.
How much does P355M cost?
P355M 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 10028-5 — Flat products made of steels for pressure purposes: Weldable fine grain steels, thermomechanically rolled — CEN (2009)
- EN 10027-2 — Numerical designation system for steels (1.8821) — CEN (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Thermomechanically rolled pressure-vessel plate (P355M/ML1/ML2) mill datasheets — European plate mills (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.