X10CrWMoVNb9-2 · Grade 92 · 9Cr-W-Mo-V-Nb · EN 10253-2 Type B
The highest-performance CrMo grade. Tungsten addition above P91 provides superior creep strength for ultra-supercritical and AUSC steam plant operating at 600–650°C. PWHT 750–780°C. Filler ER90S-B9M.
P92 PWHT is 750–780°C — slightly higher than P91's 745–775°C range. The tungsten addition alters the transformation kinetics. Filler must be ER90S-B9M (W-bearing variant) rather than standard ER90S-B9. Time-temperature charts and hardness results are included on every EN 10204 3.1 certificate.
P92 (Grade 92) was developed by adding 1.5–2.0% tungsten to the P91 composition (with a corresponding reduction in Mo to 0.30–0.60%). Tungsten has a larger atomic radius than molybdenum and provides stronger solid-solution hardening of the martensitic matrix at temperatures above 600°C — extending creep rupture life beyond what P91 achieves.
The practical result is that P92 allows either higher operating temperatures than P91 at the same wall thickness, or thinner-walled components at the same operating conditions. This weight and cost advantage is significant in large-diameter main steam headers where P91 wall thicknesses would be limiting. P92 is the material of choice for USC and AUSC plants targeting steam temperatures above 620°C.
| Element | Min | Max | Vs P91 |
|---|---|---|---|
| Carbon (C) | 0.07 | 0.13 | Similar |
| Chromium (Cr) | 8.50 | 9.50 | Similar |
| Molybdenum (Mo) | 0.30 | 0.60 | Reduced (P91: 0.85–1.05%) |
| Tungsten (W) | 1.50 | 2.00 | New addition (P91: none) |
| Vanadium (V) | 0.15 | 0.25 | Similar |
| Niobium (Nb) | 0.04 | 0.09 | Similar |
| Nitrogen (N) | 0.030 | 0.070 | Similar |
| Boron (B) | 0.001 | 0.006 | Added (P91: none) |
| Grade | Key Addition | Max Temp | Allowable at 600°C | Primary Use |
|---|---|---|---|---|
| P9 (1.7386) | 9Cr-1Mo only | 600°C | ~40 MPa | Legacy 9Cr service |
| P91 (1.4903) | V+Nb+N | 650°C | ~114 MPa | Supercritical power |
| P92 (1.4901) | W+B (reduced Mo) | 650°C | ~133 MPa | USC/AUSC, highest creep |
| EN designation | X10CrWMoVNb9-2 |
| Material number | 1.4901 |
| ASTM equivalent | A234 WP92 / Grade 92 |
| ASME P-Number | P-No.15E |
| Max temperature | ≤650°C (sustained) |
| PWHT | 750–780°C (mandatory) |
| Filler (GTAW) | ER90S-B9M (W-bearing) |
| Standard | EN 10253-2 Type B |
| Certificate | EN 10204 3.1 standard |
PWHT 750–780°C. Time-temperature chart + hardness on EN 10204 3.1. PMI on every P92 order. TÜV / Lloyd's 3.2 available for critical circuits.
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