IBR Approved · Alloy Steel (Grade 92)
ASTM A234 WP92 Buttweld Pipe Fittings
Grade 92 (9Cr-1.8W-Mo-V-Nb) tungsten-strengthened martensitic alloy steel — the highest-creep CrMo fitting grade, for ultra-supercritical power plant main steam and reheater piping to ~650°C. 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 WP92 Is Used
- ✓ Main steam and hot reheat lines in ultra-supercritical power plants
- ✓ Boiler and turbine piping at the highest steam temperatures
- ✓ Designs that need thinner walls than WP91 at the same conditions
WP92 Compared With Related Grades
How to Specify WP92 Fittings on a Purchase Order
A complete order line avoids clarification rounds. Example:
Elbow 90° LR, 12" SCH 140, ASTM A234 WP92, ASME B16.9, normalised and tempered, hardness report, PMI, EN 10204 3.1
- ✓ Ask for hardness results on every piece (≤250 HBW)
- ✓ Ask for PMI that confirms tungsten, so WP92 is not mixed with WP91
- ✓ Add IBR Form IV (Part D) for Indian boiler piping
Grade Overview
ASTM / ASME A234 WP92 — Grade 92 — is a tungsten-strengthened creep-strength-enhanced ferritic (CSEF) steel. It builds on Grade 91 by adding roughly 1.5–2.0% tungsten (with reduced molybdenum) plus boron, raising creep-rupture strength beyond WP91 and enabling thinner, lighter main steam and reheater piping in ultra-supercritical (USC) power plants operating up to about 650°C.
WP92 is supplied normalized and tempered with hardness controlled to about 250 HBW, IBR approved with Form IV (Part D). Its EN counterpart is X10CrWMoVNb9-2 (material number 1.4901).
Critical: heat treatment & PWHT control
Like Grade 91, WP92 is unforgiving of procedure deviations. Fittings are supplied normalized & tempered. Weld PWHT is mandatory within a narrow 730–780°C window (below Ac1), with hardness controlled to ≤250 HBW. Only a matching Grade 92 (B91/B92-type) filler may be used, with tight preheat and interpass control. ASME P-No. 15E, Group 1. Heat-treatment and hardness records accompany every fitting.
Chemical Composition — A234 WP92
| Element | Requirement | Note |
|---|---|---|
| Carbon (C) | 0.07 – 0.13% | — |
| Chromium (Cr) | 8.50 – 9.50% | Oxidation & creep |
| Tungsten (W) | 1.50 – 2.00% | Key creep strengthener |
| Molybdenum (Mo) | 0.30 – 0.60% | — |
| V / Nb / N | V 0.15–0.25, Nb 0.04–0.09, N 0.030–0.070 | Microalloys |
| Boron (B) | 0.001 – 0.006% | Creep stability |
Mechanical Properties — A234 WP92
| Property | Requirement |
|---|---|
| Tensile Strength (min) | 620 MPa (90 ksi) |
| Yield Strength (min) | 440 MPa (64 ksi) |
| Elongation (min) | ≥ 20% |
| Hardness | ≤ 250 HBW |
| Heat Treatment | Normalized & Tempered (mandatory) |
Equivalent Grades
| Product Form | Specification |
|---|---|
| Buttweld fittings | ASTM / ASME A234 WP92 |
| Seamless pipe | ASTM A335 P92 |
| Forgings / flanges | ASTM A182 F92 |
| EN designation | X10CrWMoVNb9-2 (W.Nr. 1.4901) |
EN 10253 equivalent: see WP92 pipe fittings on arshyapipefittings.com, and the European grade EN 1.4901 (X10CrWMoVNb9-2).
Fitting Types Available in WP92
- Elbows — 45° / 90° / 180°, LR & SR
- Tees — equal & reducing
- Reducers — concentric & eccentric
- Caps — buttweld end closures
Related grades: WP91 · WP22 · WP11 · IBR Form IV (Part D) guide · IBR grades list · WP91 for HRSGs
Testing & Inspection — WP92
- Chemical analysis of each heat, including tungsten, vanadium, niobium, nitrogen and boron — the additions that give Grade 92 its creep strength.
- Hardness checked after normalizing & tempering against the ≤250 HBW limit.
- Tensile test to ASTM A234 (620 MPa min. tensile, 440 MPa min. yield).
- Positive material identification (PMI) — the tungsten content is what tells WP92 apart from WP91, so PMI prevents a costly mix-up.
- Dimensional and visual inspection to ASME B16.9; NDE (MT / UT / RT) as specified in your purchase order.
Dimensions & Size Range — ASME B16.9
WP92 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 WP92 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.
WP92 Fittings — Frequently Asked Questions
What is the difference between WP92 and WP91?
WP92 replaces part of the molybdenum in Grade 91 with about 1.5–2% tungsten (plus a small boron addition), giving higher long-term creep strength. That allows thinner walls or higher steam temperatures in ultra-supercritical plants. See P91 vs P92 fittings.
What PWHT does WP92 need?
Post-weld heat treatment at 730–780°C, with hardness checked against the ≤250 HBW limit afterwards. Welding consumables must be matched to Grade 92 — Grade 91 filler is not a substitute.
Where is WP92 used?
Main steam and hot reheat piping in ultra-supercritical (USC) power plants, where metal temperatures approach 600–620°C and Grade 91 would need impractically thick walls.