EN 10253-2 Type B P5 · X11CrMo5 · 5Cr-0.5Mo PWHT Mandatory

1.7362 (P5) Pipe Fittings

EN 10253-2 Type B buttweld pipe fittings in 1.7362 — P5 CrMo alloy steel (X11CrMo5, 5Cr-0.5Mo). The 5% chromium content places P5 on a favourable position on the API 941 Nelson curve, providing resistance to high-temperature hydrogen attack (HTHA) and sulfidation in oil refinery service. Used in hydrotreater, hydrocracker, and atmospheric distillation unit (ADU) process piping at elevated temperatures.

Cr Content

ASTM Equivalent

WP5 / ASTM A335 P5

Key Standard

API 941 (Nelson)

PWHT Mandatory

1.7362 (P5) requires post-weld heat treatment. PWHT temperature: 720–760°C. As-welded hardness exceeds limits and the HAZ is susceptible to hydrogen cracking without PWHT. All fittings supplied with PWHT documented on EN 10204 3.1 certificate.

Refinery CrMo Grade by Cr Content

Grade	W.Nr.	Cr %	API 941 Advantage	Typical Refinery Use
P11	1.7335	1.25%	Limited	Low-temp steam, secondary piping
P22	1.7380	2.25%	Moderate	Hydrotreater, hydrocracker HP piping
P5 (this grade)	1.7362	5%	Good — Nelson curve margin	ADU hot section, crude transfer
P9	1.7386	9%	Excellent	Highest-temp refinery, FCCU

Cross-References

W.Nr.	1.7362
EN Name	X11CrMo5
ASTM Grade	WP5 / P5
Composition	5Cr-0.5Mo

Welding

Filler: ER80S-B6 (AWS A5.28). Preheat 200°C minimum. PWHT 720–760°C. No high-Mn or high-Si fillers.

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Testing & Inspection

✓ Chemical analysis against EN 10216-2 / EN 10253-2
✓ Tensile test, with impact test where the standard or your order requires it
✓ Hardness check after PWHT
✓ 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.

Size	OD (mm)
DN 15	21.3
DN 20	26.9
DN 25	33.7
DN 32	42.4
DN 40	48.3
DN 50	60.3
DN 65	76.1
DN 80	88.9
DN 100	114.3
DN 125	139.7
DN 150	168.3
DN 200	219.1
DN 250	273.0
DN 300	323.9
DN 350	355.6
DN 400	406.4
DN 450	457.0
DN 500	508.0
DN 600	610.0

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: P5 (1.7362) Fittings

Why is P5 (1.7362) used in oil refineries?

Its 5% chromium content gives a favourable position on the API 941 Nelson curve, so it resists high-temperature hydrogen attack and sulfidation in refinery service.

What is the composition of 1.7362?

X11CrMo5: a 5Cr-0.5Mo chromium-molybdenum alloy steel.

Which certificates come with P5 fittings?

EN 10204 3.1 as standard, or 3.2 with third-party inspection, plus PED documentation for European projects.