Alloy steel P91.
P91 is a modified 9% chromium, 1% molybdenum steel with vanadium, niobium and nitrogen.
Quick details
| Material grade | Alloy steel P91 (UNS K90901) |
|---|---|
| Forms | Pipes, Tubes, Sheets & plates, Butt-weld fittings, Flanges |
| Usage / application | Supercritical boiler headers, Main steam piping, Heat-recovery steam generators |
| Test certificate | EN 10204 3.1 mill test certificate; 3.2 on request |
| Business type | Stockist and supplier |
| Location | Kumbharwada, Mumbai 400004, Maharashtra |
Also searched as: Alloy steel P91, 9Cr-1Mo-V, UNS K90901, W.Nr 1.4903, X10CrMoVNb9-1
Product information for purchasing teams
P91 is a modified 9% chromium, 1% molybdenum steel with vanadium, niobium and nitrogen. Its creep strength is much higher than P22, so thinner walls can be used in supercritical boilers and high-temperature headers. It needs careful pre-heat and post-weld heat treatment.
Exact specification, availability and commercial details are confirmed against your enquiry.
Product forms and standards
| Form | Standard |
|---|---|
| Pipes | ASTM A335 / ASME SA335 P91 |
| Tubes | ASTM A213 T91 |
| Sheets & plates | ASTM A387 Grade 91 Class 2 |
| Butt-weld fittings | ASTM A234 WP91 |
| Flanges | ASTM A182 F91 |
Equivalent grades
| Grade | UNS | Werkstoff Nr. | EN / BS | JIS |
|---|---|---|---|---|
| Alloy steel P91 | K90901 | 1.4903 | X10CrMoVNb9-1 | STPA 28 |
Chemical composition, %
| Grade | C | Mn | Si | P | S | Cr | Mo | V | Nb | N |
|---|---|---|---|---|---|---|---|---|---|---|
| Alloy steel P91 | 0.08 – 0.12 | 0.30 – 0.60 | 0.20 – 0.50 | ≤ 0.020 | ≤ 0.010 | 8.00 – 9.50 | 0.85 – 1.05 | 0.18 – 0.25 | 0.06 – 0.10 | 0.030 – 0.070 |
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength | ≥ 585 MPa |
| Yield strength | ≥ 415 MPa |
| Elongation | ≥ 20% longitudinal |
| Hardness | 190 – 250 HB |
Values per ASTM A335 P91 Type 1. Confirm against the current edition of the standard and your purchase specification.
Density: 7.77 g/cm³
Applications
- Supercritical boiler headers
- Main steam piping
- Heat-recovery steam generators
- High-temperature refinery service
Questions buyers ask
What are the equivalent grades of Alloy steel P91?
Alloy steel P91 is UNS K90901, Werkstoff 1.4903, EN X10CrMoVNb9-1 and JIS STPA 28.
In which forms is Alloy steel P91 available?
Pipes to ASTM A335 / ASME SA335 P91; Tubes to ASTM A213 T91; Sheets & plates to ASTM A387 Grade 91 Class 2; Butt-weld fittings to ASTM A234 WP91; Flanges to ASTM A182 F91.
What is the density of Alloy steel P91?
About 7.77 g/cm³ (7,770 kg/m³).
Where is Steel Impex India located?
Steel Impex India is at 231/235, Sant Sena Maharaja Marg, 2nd Kumbharwada, Mumbai 400004, and supplies across India.