P91 / X10CrMoVNb9-1 vs P92 / X10CrWMoVNb9-2
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
P91 / X10CrMoVNb9-1
Pipe & Tube Steel
P91 is the 9Cr-1Mo-V-Nb creep-strength-enhanced ferritic steel that made modern ultra-supercritical power stations possible. Nitrogen and niobium carbonitrides hold its creep strength at 600 °C far beyond the older 2.25Cr and 12Cr grades, so main-steam pipework runs thinner and lighter.
Standards: DIN 1.4903 · AISI ASTM A335 P91 / A213 T91 · GB 10Cr9Mo1VNb (GB/T 5310)
P92 / X10CrWMoVNb9-2
Pipe & Tube Steel
P92 takes the P91 recipe and swaps part of the molybdenum for 1.5–2% tungsten plus a boron addition, buying roughly 30% more creep strength again. It is the standard material for the hottest main-steam lines in 600 °C-class ultra-supercritical boilers.
Standards: DIN 1.4901 · AISI ASTM A335 P92 / A213 T92 · GB 10Cr9MoW2VNbBN (GB/T 5310)
Chemical composition compared (%)
| Element | P91 / X10CrMoVNb9-1 | P92 / X10CrWMoVNb9-2 |
|---|---|---|
| C | 0.08–0.12 | 0.07–0.13 |
| Si | 0.20–0.50 | ≤0.50 |
| Mn | 0.30–0.60 | 0.30–0.60 |
| P | ≤0.020 | ≤0.020 |
| S | ≤0.010 | ≤0.010 |
| Cr | 8.00–9.50 | 8.50–9.50 |
| Mo | 0.85–1.05 | 0.30–0.60 |
| V | 0.18–0.25 | 0.15–0.25 |
| Nb | 0.06–0.10 | 0.04–0.09 |
| N | 0.03–0.07 | 0.03–0.07 |
| Ni | ≤0.40 | ≤0.40 |
| W | — | 1.50–2.00 |
| B | — | 0.001–0.006 |
Properties compared
| Property | P91 / X10CrMoVNb9-1 | P92 / X10CrWMoVNb9-2 |
|---|---|---|
| Yield strength | ≥415 MPa | ≥440 MPa |
| Tensile strength | 585–760 MPa | 620–850 MPa |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
| Creep service | Power plant steam to ~600 °C | Steam to ~620 °C |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: P91 / X10CrMoVNb9-1 · P92 / X10CrWMoVNb9-2. Substitution decisions for certified parts stay with the design authority.