IBR Approved · Alloy Steel (CrMo)
ASTM A234 WP5 Buttweld Pipe Fittings
5Cr-0.5Mo chromium-molybdenum alloy steel fittings for refinery fired heaters, catalytic reforming and high-temperature hydrogen service. Elbows, tees, reducers and caps to ASME B16.9 / B16.28, IBR approved with Form IV (Part D) (formerly Form III-C), EN 10204 3.1 / 3.2 traceable.
Where WP5 Is Used
- ✓ Refinery fired heaters and furnace piping
- ✓ Hydroprocessing and sulphur-bearing process lines
- ✓ High-temperature refinery transfer lines
WP5 Compared With Related Grades
How to Specify WP5 Fittings on a Purchase Order
A complete order line avoids clarification rounds. Example:
Elbow 90° LR, 6" SCH 80, ASTM A234 WP5, ASME B16.9, normalised and tempered, PMI, EN 10204 3.1
- ✓ Ask for the heat treatment record and hardness results
- ✓ Ask for PMI on every piece to separate WP5 from other CrMo grades
- ✓ Add 3.2 witnessed inspection if your specification requires it
Grade Overview
ASTM / ASME A234 WP5 is a 5Cr-0.5Mo chromium-molybdenum alloy steel. Its 5% chromium content gives strong resistance to high-temperature hydrogen attack (HTHA) and sulphidic corrosion, making it a standard grade for refinery fired heater coils, catalytic reforming and crude/vacuum unit piping in hot hydrogen and sulphur-bearing environments.
WP5 fittings are supplied IBR approved with Form IV (Part D) for boiler and steam service. The EN counterpart is X11CrMo5 (material number 1.7362).
PWHT is mandatory
All WP5 welds require post-weld heat treatment, typically 720–760°C, to temper the hardened heat-affected zone and avoid hydrogen cracking. Post-PWHT hardness and the time-temperature record are reported on the EN 10204 3.1 certificate. Filler metal: ER80S-B6. ASME P-No. 5B.
Chemical Composition — A234 WP5
| Element | Requirement | Note |
|---|---|---|
| Carbon (C) | ≤ 0.15% | — |
| Chromium (Cr) | 4.0 – 6.0% | HTHA / sulphidic resistance |
| Molybdenum (Mo) | 0.45 – 0.65% | Creep resistance |
| Mn / Si | Mn 0.30–0.60, Si ≤0.50 | — |
| P / S | ≤ 0.030% each | Impurity limits |
Mechanical Properties — A234 WP5 (Class 1)
| Property | Requirement |
|---|---|
| Tensile Strength | 415 – 585 MPa (60 – 85 ksi) |
| Yield Strength (min) | 205 MPa (30 ksi) |
| Elongation (min) | ≥ 20% (per specification formula) |
| Heat Treatment | Annealed or normalised & tempered; PWHT after welding |
Equivalent Grades
| Product Form | Specification |
|---|---|
| Buttweld fittings | ASTM / ASME A234 WP5 |
| Seamless pipe | ASTM A335 P5 |
| Forgings / flanges | ASTM A182 F5 |
| EN designation | X11CrMo5 (W.Nr. 1.7362) |
EN 10253 equivalent: see WP5 pipe fittings on arshyapipefittings.com, and the European grade EN 1.7362 (X11CrMo5).
Fitting Types Available in WP5
- Elbows — 45° / 90° / 180°, LR & SR
- Tees — equal & reducing
- Reducers — concentric & eccentric
- Caps — buttweld end closures
Related grades: WP9 · WP11 · WP22 · IBR Form IV (Part D) guide · IBR grades list
Testing & Inspection — WP5
- Chemical analysis of each heat, confirming 5Cr-0.5Mo.
- Tensile and hardness tests to ASTM A234 for the class ordered (Class 1 shown above; Class 3 on request).
- Positive material identification (PMI) to confirm chromium and molybdenum — standard practice in refinery and hydrogen service.
- Dimensional and visual inspection to ASME B16.9; NDE (MT / UT / RT) as specified in your purchase order.
Dimensions & Size Range — ASME B16.9
WP5 fittings are made to ASME B16.9 (long-radius) and ASME B16.28 (short-radius elbows) dimensions, from 1/2" to 48" NB and above, in schedules SCH 20 to SCH 160 / XXS. Wall thickness matches the connecting pipe schedule. Centre-to-end dimensions for the most-ordered sizes:
| NPS | Outside diameter (mm) | 90° LR elbow “A” (mm) | 45° LR elbow “B” (mm) | Equal tee “C” (mm) |
|---|---|---|---|---|
| 1/2" | 21.3 | 38 | 16 | 25 |
| 1" | 33.4 | 38 | 22 | 38 |
| 2" | 60.3 | 76 | 35 | 64 |
| 3" | 88.9 | 114 | 51 | 86 |
| 4" | 114.3 | 152 | 64 | 105 |
| 6" | 168.3 | 229 | 95 | 143 |
| 8" | 219.1 | 305 | 127 | 178 |
| 10" | 273.1 | 381 | 159 | 216 |
| 12" | 323.9 | 457 | 190 | 254 |
| 16" | 406.4 | 610 | 254 | 305 |
| 20" | 508.0 | 762 | 318 | 381 |
| 24" | 610.0 | 914 | 381 | 432 |
Long-radius elbows have a centre-line radius of 1.5 × NPS; short-radius (ASME B16.28) 1.0 × NPS. Full tables to NPS 48, reducing tees, reducers and caps are available with every quotation. For EN 10253 dimensions see arshyapipefittings.com.
Export Documentation & Packing
We ship WP5 fittings to projects outside India with the documents EPC contractors and inspection agencies expect:
- Mill test certificate — EN 10204 3.1 as standard; 3.2 with third-party witness
- Third-party inspection — Bureau Veritas, TÜV, Lloyd’s Register, SGS, DNV or the client’s own inspector
- IBR Form IV (Part D) — for boiler piping on Indian Boiler Regulations projects
- Traceability — every fitting marked with grade, size, schedule and heat number, matching the certificate
- Packing — seaworthy wooden cases or pallets, bevel ends protected with end caps
- Shipping documents — commercial invoice, packing list and certificate of origin; FOB, CFR or CIF terms
Send your BOQ through the RFQ form (Excel or PDF attachments accepted) or on WhatsApp — quotations are usually issued within 24 hours.
WP5 Fittings — Frequently Asked Questions
Where are WP5 fittings used?
Mainly in refineries — furnace transfer lines and hot process piping where high-temperature sulphidation from sulphur-bearing crude and hydrogen attack rule out carbon steel and lower Cr-Mo grades. See P5 and P9 in refinery service.
What is the difference between WP5 Class 1 and Class 3?
Same 5Cr-0.5Mo chemistry, different strength. Per ASTM A234: Class 1 — 415–585 MPa tensile, 205 MPa min. yield; Class 3 — 520–690 MPa tensile, 310 MPa min. yield.
Is PWHT required for WP5?
Yes — post-weld heat treatment at 720–760°C is mandatory after welding.