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EN 10253 Type B Specialists
EN 1.0566 P355NL1 EN 10028-3 LTCS −50°C Charpy ≈ ASTM WPL6 (higher yield)

P355NL1 (1.0566) High-Yield LTCS Pipe Fittings

High-yield low-temperature normalised carbon steel buttweld fittings to EN 10028-3. Charpy impact tested at −50°C with 40 J average requirement. Not an equivalent of ASTM A420 WPL3, which is a 3.5% Ni grade (EN 12Ni14, 1.5637) — used for LNG satellite station piping, cold gas headers, and cryogenic process plant where high wall thickness would otherwise be needed with the lower-yield P275NL1.

Chemical Composition — P355NL1 (EN 10028-3)

ElementRange / Max %
Carbon (C)≤0.18
Silicon (Si)≤0.60
Manganese (Mn)1.00–1.70
Phosphorus (P)≤0.025
Sulphur (S)≤0.010
Aluminium (Al)≥0.020
Nb (optional)≤0.05
V (optional)≤0.12

Higher Mn content (up to 1.70%) compared to P275NL1 provides the increased yield strength. Al deoxidation for fine-grained microstructure essential for sub-zero Charpy performance.

Mechanical Properties — P355NL1

PropertyValue
Yield Strength (Rp0.2, min)355 MPa
Tensile Strength (Rm)490–630 MPa
Elongation (A, min)22%
Charpy Test Temperature−50°C
Charpy KV (avg, min)40 J (longitudinal)
Charpy KV (individual min)28 J
Heat TreatmentNormalised (N)

P355NL1 vs ASTM A420 WPL3

PropertyASTM WPL3EN P355NL1
StandardASTM A420EN 10028-3
Ni content3.18–3.82%None (Mn-based)
Charpy temp−101°C (−150°F)−50°C
Min YS275 MPa355 MPa
Charpy avg27 J40 J
Important: P355NL1 is NOT a direct substitute for ASTM WPL3 at temperatures below −50°C. For services requiring −101°C (e.g. LNG at full-scale terminals), specify either ASTM A420 WPL3 (3.5Ni) or EN 10028-4 nickel alloy steel grades (13MnNi6-3 or X10Ni9 for LNG).

When to Choose P355NL1 over P275NL1

  • ›Wall thickness reduction: 355 MPa yield vs 275 MPa reduces required wall by ~22% at the same operating pressure — significant for large-bore cold headers
  • ›LNG satellite and regasification: Required where design pressure is high and −50°C MDMT is sufficient (not going below −50°C)
  • ›Offshore cold service: Arctic platforms where MDMT is −46°C to −50°C and higher yield strength is needed for weight reduction
  • ›Cold gas high-pressure headers: Compressor station headers and pig launchers/receivers in cold climate installations
Related grades: P275NL1 (1.0488) — lower yield LTCS · ASTM WPL3 (−101°C, 3.5Ni) · WPL6

Quote P355NL1 LTCS Fittings

EN 10253-2 Type B. Charpy impact certificates at −50°C. EN 10204 3.1. PED 2014/68/EU.

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Testing & Inspection

  • ✓ Chemical analysis against EN 10028-3 / EN 10253-2
  • ✓ Tensile test, with impact test where the standard or your order requires it
  • ✓ Charpy impact test at −50°C (40 J average)
  • ✓ PMI (positive material identification) on every order
  • ✓ Visual and dimensional inspection to EN 10253
  • ✓ NDT (UT, RT, MT or PT) when your order or code calls for it
  • ✓ EN 10204 3.1 certificate as standard; 3.2 with TÜV, Lloyd's Register, Bureau Veritas, DNV or your own inspector

Size Range

DN15–DN600 and larger. Outside diameters follow the EN 10220 / EN ISO 1127 pipe series; wall thickness is matched to your connecting pipe.

SizeOD (mm)
DN 1521.3
DN 2026.9
DN 2533.7
DN 3242.4
DN 4048.3
DN 5060.3
DN 6576.1
DN 8088.9
DN 100114.3
DN 125139.7
DN 150168.3
DN 200219.1
DN 250273.0
DN 300323.9
DN 350355.6
DN 400406.4
DN 450457.0
DN 500508.0
DN 600610.0

Export Documents & Packing

  • ✓ Commercial invoice, packing list and certificate of origin
  • ✓ EN 10204 certificates with heat-number traceability
  • ✓ PED 2014/68/EU and AD 2000-Merkblatt W0 documentation for European projects
  • ✓ Seaworthy wooden cases or pallets, bevel ends protected, marked to your instructions
  • ✓ FOB, CFR or CIF delivery terms
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Frequently Asked Questions: P355NL1 (1.0566) Fittings

What is the ASTM equivalent of P355NL1?

There is no exact ASTM equivalent. By impact temperature it is closest to ASTM A420 WPL6 (−46°C), with a higher yield strength. ASTM A420 WPL3 is a 3.5% Ni grade whose EN counterpart is 12Ni14 (1.5637).

What impact test applies to P355NL1 fittings?

Charpy impact testing at −50°C with a 40 J average requirement.

Where are P355NL1 fittings used?

LNG satellite station piping, cold gas headers and cryogenic process plant where higher strength is needed.

Supplying an Indian boiler or ASME B16.9 project? The closest ASTM grade is listed on our group site ibrfittings.com: ASTM A420 WPL6 fittings.

Further reading