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EN 10028-3 P355NL2 is a normalized, weldable fine-grain steel for pressure purposes. The designation encodes exactly what the grade guarantees: P = steel for pressure equipment; 355 = 355 MPa minimum yield in the thinnest sections; N = normalized (or normalized-rolled); L2 = the more demanding low-temperature toughness class, with Charpy V-notch impact energy guaranteed at −50 °C. Its EN material number is 1.1106. It is bought where a pressure vessel, storage tank or low-temperature process vessel must stay tough and safe well below zero — and where the designer wants a normalized plate rather than a quenched-and-tempered one.
P355NL2 belongs to EN 10028-3, the part of the European pressure-equipment material standard that covers normalized fine-grain plate. It shares its chemistry and its yield/tensile ladder with P355N, P355NH and P355NL1; what sets NL2 apart is the −50 °C impact requirement. In older German and Italian practice the same steel appears as EStE 355 (DIN 17102) and Fe510-2-KG respectively.
355 MPa minYield Strengthat t ≤ 16 mm; steps down with thickness
What this page publishes, and what must be confirmed on the mill certificate when you enquire.
Item
Specification
Executive Standard
EN 10028-3 (flat products made of steels for pressure purposes — weldable fine-grain steels, normalized). Also referenced for other product forms: EN 10216-3 (seamless tubes), EN 10217-3 (welded tubes), EN 10222-4 (forgings)
Steel Grade
P355NL2 (EN material number 1.1106)
Steel Category
Weldable fine-grain steel for pressure purposes, low-temperature quality (L2)
Product Form
Hot-rolled plate, normalized (+N)
Thickness Range
Standard covers up to 250 mm; the exact rolled thickness and commercial range are confirmed with the mill
Width & Length
Per mill rolling programme; cut-to-length and cut-to-shape available
Carbon Equivalent (CEV max)
0.43 (t ≤ 60 mm); 0.45 (60 – 250 mm)
MOQ
1 ton (mixed sizes negotiable)
Lead Time by Quantity
1 – 10 t: about 5 days; 10 – 50 t: about 10 days; > 50 t: negotiable
EN 10204 3.1 / 3.2; UT, Charpy at −50 °C, through-thickness Z15–Z35, HIC / NACE on request
P355NL2 is a standard grade, but only its tested values are guaranteed. EN 10028-3 fixes the chemistry limits, the yield/tensile/elongation ladder and the −50 °C impact energy. Actual heat analysis and mechanical results are recorded on the EN 10204 certificate of the lot you buy — confirm the exact figures against that document.
03How to Read the Grade
Every character of P355NL2 is a specification, not a marketing name.
Part
Meaning
P
Steel for pressure purposes (the EN 10028 family)
355
Minimum yield strength of 355 MPa in the thinnest sections (t ≤ 16 mm); it steps down as thickness rises
N
Normalized (or normalized-rolled) — the plate is delivered in the normalized condition
L2
Low-temperature quality, the second and colder class: Charpy V-notch impact energy guaranteed at −50 °C (27 J transverse). L1 would be −40 °C
1.1106
The EN material number (Werkstoffnummer) — the unambiguous way to call up this exact steel in European procurement
04Equivalent Grades
P355NL2 belongs to the EN 10028-3 normalized P355 family. The first table places it next to its three siblings — they share chemistry and the same yield/tensile ladder; only the qualified impact temperature differs. The second table lists the closest equivalents by standard that we also supply, each opening its own page.
Pick the grade by the temperature your design demands. All four P355-family grades share the same chemistry and the same yield/tensile ladder; the only thing that changes is the qualified impact temperature (and, for NH, the elevated-temperature property). If your lowest design metal temperature is −50 °C, NL2 is the one to order — NL1 (−40 °C) is not enough. For the low-alloy boiler grades, see 16Mo3 and 13CrMo44.
05Chemical Composition
Ladle (cast) analysis limits in weight percent, per EN 10028-3. Product-analysis tolerances apply when ordered (per EN 10028-1).
Element
Limit (% by mass)
C
≤ 0.18
Si
≤ 0.50
Mn
1.10 – 1.70
P
≤ 0.020
S
≤ 0.010
Al (total)
≥ 0.020 (grain-refining)
N
≤ 0.012
Cr
≤ 0.30
Cu
≤ 0.30
Mo
≤ 0.08
Nb
≤ 0.05
Ni
≤ 0.50
Ti
≤ 0.03
V
≤ 0.10
Nb + Ti + V
< 0.12 (combined micro-alloying)
Correction against some supplier pages. A few commercial listings (including an older version of this product page) showed P 0.025, S 0.015, Nb 0.005 and left aluminium blank. Those figures are wrong for this grade. EN 10028-3 requires P ≤ 0.020, S ≤ 0.010, Nb ≤ 0.05 and Al(total) ≥ 0.020 (the aluminium is what delivers the fine grain). The limits above are the standard values; your certificate shows what the heat actually made.
05Mechanical Properties
Minimum values in the normalized (+N) condition, read against nominal thickness. Every figure is a floor the heat is tested against — not a prediction of your certificate.
Thickness (mm)
Yield ReH min (MPa)
Tensile Rm (MPa)
Elongation A min (%)
t ≤ 16
355
490 – 630
22
16 < t ≤ 40
345
490 – 630
22
40 < t ≤ 60
335
490 – 630
22
60 < t ≤ 100
315
470 – 610
21
100 < t ≤ 150
305
460 – 600
21
150 < t ≤ 250
295
450 – 590
21
Low-temperature Charpy V-notch impact (the NL2 requirement)
Test temperature
−50 °C
−40 °C
−20 °C
0 °C
+20 °C
KV, transverse (J) — NL2 guarantee
27 min
30 – 33
40 – 47
60
70
KV, longitudinal (J) — typical
40 – 42
45 – 50
55 – 70
75 – 90
85 – 100
Two corrections against the old listing. First, the defining NL2 toughness is 27 J at −50 °C, transverse — not the −20 / 0 / +20 °C 65 / 90 / 100 J figures some pages quote, which are warm-temperature longitudinal values and not the grade's guarantee. Second, the yield/tensile ladder has six thickness bands from ≤ 16 to 150 – 250 mm, not the two bands (16–35 / 35–50) sometimes shown. Always quote the −50 °C figure and read yield against your actual thickness.
07Heat Treatment & Delivery Condition
The condition is not a free choice on this grade — NL2 is defined by being normalized.
Item
Requirement
Remarks
Delivery Condition
Normalized (+N)
Plate is austenitized and air-cooled (normalized); it is not supplied quenched-and-tempered as NL2
Steelmaking
KilledFine austenitic grain
Fine grain comes from aluminium (Al ≥ 0.020) and controlled Nb/Ti/V; carried through EN 10028-1
Maximum Thickness
250 mm (standard scope)
Strength and impact step down with thickness; confirm the values for your band
Re-heat treatment
Not required / not recommended
Normalizing already provides the fine grain and low-temperature toughness; avoid thermal cycles that would coarsen the grain
The condition has to survive fabrication. Normalized plate keeps its properties through normal cutting and welding, but heavy hot forming or a stress-relief cycle above the transformation range can move those properties. Where the vessel will be hot formed or stress relieved, test coupons go through a simulated PWHT cycle and are tested afterwards, so the certificate reflects the condition the vessel will actually be in. Say at enquiry stage whether the plate will be hot formed or PWHT-treated — it changes what we have to certify.
08What This Plate Has to Prove
Six items come up again and again on a low-temperature pressure-vessel enquiry. None is automatic — each has to be named on the order.
UTinternal soundness
Ultrasonic examination
A plate this thick and this highly stressed has to be sound through its full section, so ultrasonic examination to EN 10160 (or EN 10228 / customer spec) is the norm rather than the exception. It is also the line most often left off an enquiry, and the one that matters most once the plate is welded into a seam that cannot be repaired from inside.
CVNtoughness at −50 °C
Charpy V-notch impact at −50 °C
This is the whole point of the NL2 grade. The 27 J transverse guarantee only exists if you ask for it at −50 °C on transverse specimens. State the temperature and the acceptance value; longitudinal values run considerably higher and must not be quoted in place of the transverse requirement.
PWHTafter heat treatment
Simulated post-weld heat treatment
Almost every NL2 shell is welded and then stress relieved, and the properties have to survive that. Coupons are put through a simulated PWHT cycle and tested afterwards, so the certificate shows the properties in the condition the vessel will actually see rather than in the as-delivered condition.
Zthrough-thickness
Short-transverse reduction of area
Heavy nozzle-to-shell connections and large restrained attachments can tear plate in the through-thickness direction. Where the design has that restraint — and thick-wall low-temperature shells frequently do — Z15, Z25 or Z35 properties are called up. They come from steelmaking cleanliness and low sulphur, not from heat treatment.
HICsour service
Hydrogen-induced cracking resistance
P355NL2 is regularly specified for sour or wet-H2S service — refinery separators, amine contactors, sour gas plant — where HIC and sulphide stress cracking testing to NACE MR0175 / ISO 15156 or NACE MR0103 is added on top of reduced sulphur and controlled inclusion shape. This has to be raised at enquiry: it changes the steel route as well as the testing.
3.2documentation
Traceability and EN 10204 certification
Standard supply is a mill test certificate to EN 10204 type 3.1 giving heat number, chemical analysis and mechanical results for the actual heat delivered, with the plate marked so it can be traced through fabrication. Where the project asks for independent verification, type 3.2 with third-party witness — SGS, BV, Lloyd’s, DNV or your own inspector — is arranged with the order.
None of this turns the page into a code book. Which of these tests applies, at what acceptance level and at what sampling frequency, is set by your purchase specification and the vessel code you build to — not by us, and not by the tables above.
09Typical Applications
Where normalized plate with a −50 °C toughness guarantee does the work.
Low-Temperature Storage Tanks
LPG, propane, ammonia and other refrigerated or cold-storage tanks where the shell must stay tough at sub-zero metal temperature.
Pressure Vessels & Separators
Refinery and petrochemical reactors, separators, scrubbers and process columns in cold-climate or low-temperature service.
Cryogenic Process Equipment
Spheres and pressure storage for gases handled at low temperature, where the combination of yield and guaranteed impact energy is what the design buys.
Boilers & Steam Drums
Boiler shells, steam drums and headers for plant that operates in cold climates, where the low-temperature impact margin is needed.
Heat Exchangers & Reactors
Shells, channels and pressure-containing components generally built to a pressure-equipment code, where certification matters as much as strength.
Cold-Climate Structures
Wind-turbine towers, offshore and Arctic structures where the steel must resist brittle fracture at low service temperature.
Selection advice: choose P355NL2 only where the design's lowest metal temperature reaches −50 °C. If your duty is warmer, P355NL1 (−40 °C) or even P355N will do the job at lower cost and with more stock availability — tell us the temperature and we will point to the right grade.
10Processing, Testing & Supply
From plate to a cut, certified, ready-to-fit pressure-part.
1
Cutting & Edge Prep
Flame, plasma or laser cutting to drawing or a nesting layout, with weld-edge bevels prepared to the joint detail you are fabricating.
2
Forming
Rolling to shell-course radius and press forming of head blanks, cold where the thickness allows; hot forming followed by the heat treatment that restores the normalized properties.
3
Heat-Treatment Verification
Simulated PWHT coupons tested where the order calls for it, so the certificate reflects the post-fabrication condition, not just the as-delivered one.
4
Inspection & Certified Delivery
UT, Charpy at −50 °C, through-thickness testing where required, and surface inspection; EN 10204 3.1 with heat-number traceability, 3.2 or third-party witness arranged on request.
Quote checklist — faster if you send: the standard and edition (EN 10028-3), the grade and material number (P355NL2 / 1.1106), thickness, width and length, quantity, the lowest design metal temperature and the impact requirement, any HIC or through-thickness (Z) requirement, the certification type, and the destination port.
11Frequently Asked Questions
Q1What does P355NL2 actually mean?
P355NL2 is an EN 10028-3 fine-grain pressure-vessel steel. P = pressure purposes, 355 = 355 MPa minimum yield at up to 16 mm, N = normalized, L2 = the colder low-temperature impact class with 27 J guaranteed at −50 °C (transverse). Its material number is 1.1106. It is the coldest-toughness member of the normalized P355 family.
Q2P355NL2 or P355NL1 — which do I need?
It depends on your lowest design metal temperature. NL1 is qualified to −40 °C and NL2 to −50 °C, both at 27 J transverse. If your calculation requires toughness at −50 °C, NL2 is mandatory — NL1 will not satisfy it. If your duty is warmer, NL1 is usually cheaper and more available. We can confirm the right choice from your design temperature.
Q3Is P355NL2 the same as P355GH or A516 Grade 70?
No. P355GH (EN 10028-2) is a non-alloy elevated-temperature pressure steel with no low-temperature impact guarantee. A516 Grade 70 is a normalized American pressure-vessel plate (~260 MPa yield) with a different chemistry and impact basis. P355NL2 is a fine-grain normalized steel whose defining feature is the −50 °C impact energy. They are not interchangeable under a code without the responsible engineer signing the substitution off.
Q4Can P355NL2 be welded?
Yes — it is a weldable fine-grain steel. Its carbon equivalent is moderate (CEV max 0.43 up to 60 mm, 0.45 above), so with low-hydrogen consumables, appropriate preheat for the thickness and a qualified procedure it welds well. Because it is normalized, avoid thermal cycles that would coarsen the grain or remove the low-temperature toughness; agree any PWHT with whoever is responsible for the vessel.
Q5What thickness, how fast, what paperwork?
From 1 ton, with typical lead times of about 5 days for 1–10 t, about 10 days for 10–50 t and negotiable above 50 t. Each heat ships with an EN 10204 3.1 mill test certificate carrying ladle analysis and mechanical results; 3.2 or third-party inspection can be arranged on request. Standard covers plate up to 250 mm.
Q6Your old page showed different chemistry and impact figures — which is right?
The figures on this page are the EN 10028-3 standard values. The older listing was wrong in several places: it showed P 0.025 (standard 0.020), S 0.015 (standard 0.010), Nb 0.005 (standard 0.05) and left aluminium blank (standard requires Al ≥ 0.020). It also quoted impact as −20 / 0 / +20 °C 65 / 90 / 100 J, which are warm-temperature longitudinal values — the NL2 guarantee is 27 J at −50 °C, transverse. The yield ladder was also shown in only two bands rather than the standard six. We now publish the standard values and flag the differences in the relevant note boxes.
Sources and limits: the figures on this page are reference information drawn from EN 10028-3 (and the related EN 10028-1 / EN 10216-3 / EN 10222-4 product-form standards) and published steel data sheets. P355NL2 is defined by EN 10028-3 with material number 1.1106; chemistry limits, the yield/tensile/elongation ladder and the 27 J at −50 °C transverse impact are the standard requirements, while actual heat values are recorded on the EN 10204 certificate of the lot supplied. Older listings of this grade contained errors (P, S, Nb, Al and the impact/yield presentation) that we have corrected against the standard. BBN supplies, cuts and processes the plate.
Get Your EN 10028-3 P355NL2 Quotation Now
Send us your standard and edition, grade and material number (P355NL2 / 1.1106), thickness, width and length, quantity, lowest design metal temperature and impact requirement. We will reply with what the mill can roll and certify at that thickness, the −50 °C impact testing available, plate or cut-length options, mill price and production lead time — and tell you plainly if P355NL1 would meet the duty at lower cost.
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