Steel P92 · heat-treated state
Steel P92 N&T
Properties of the N&T condition, compared with the other P92 tempers.
The only condition allowed for pressure service — tempered martensite with fine MX/M23C6 precipitation giving the design creep strength.
What is P92 N&T?
P92 N&T is P92 heat treated to N&T — the only condition allowed for pressure service — tempered martensite with fine MX/M23C6 precipitation giving the design creep strength. P92 N&T has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 70% of steel grades. Elongation at break is 22% and the elastic modulus is 218 GPa (31.6 Msi). P92 N&T has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 91% of steel grades. It melts at 1,425°C (2,597 °F). HR is the default condition FabDigit quotes; N&T is available on request or by drawing note.
Advantages
- High service temperature — 620°C (1,148 °F), better than 99% of steel grades
- Good corrosion resistance — 30/100, better than 95% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
Limitations
- High embodied carbon — 2.6 kg CO₂/kg, worse than 86% of steel grades
- Poor heat conductor — 28 W/m·K (16.2 BTU/hr·ft·°F), worse than 85% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
P92 N&T properties
Typical room-temperature values for P92 N&T — 14 properties are specific to this condition; the rest are grade-level values shared by every P92 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
P92 N&T has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 91% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
P92 N&T has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 70% of steel grades. Elongation at break is 22% and the elastic modulus is 218 GPa (31.6 Msi).
Thermal6
P92 N&T is rated for continuous service to 620°C (1,148 °F). It conducts heat at 28 W/m·K (16.2 BTU/hr·ft·°F), worse than 85% of steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical2
P92 N&T has an electrical resistivity of 5.9×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of P92 N&T takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 88% of steel grades. Typical recycled content is 30%.
Manufacturability7
P92 N&T's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (40/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other P92 tempers and conditions
P92 is also supplied in 4 other conditions. The full side-by-side table is on the P92 overview.
- HRDefaultAs-hot-worked mill stock with uncontrolled, position-dependent properties; never acceptable for code pressure parts without normalizing and tempering.620 MPa yield · 29 HRC
- NormalizedProcess-only condition after air cooling from austenitizing — hard and brittle, must be tempered before any service or hydro test.900 MPa yield · 43 HRC
- Q&TUsed on thick forgings and castings where air cooling cannot fully harden the section; slightly higher strength than N&T at similar toughness.580 MPa yield · 23 HRC
- N&TThe only condition allowed for pressure service — tempered martensite with fine MX/M23C6 precipitation giving the design creep strength.540 MPa yield · 21 HRC
- AnnealedSoftened condition for heavy machining or cold forming; the creep properties are only restored after a full re-normalize and temper.400 MPa yield · 185 HB
Working with P92 N&T
Is P92 easy to machine?
Machine in the N&T (≤250 HB) or annealed condition with rigid setups, coated carbide, moderate speed and heavy feed; the fine MX carbonitrides are abrasive and work-hardening is noticeable.
Can P92 be welded?
GTAW root / SMAW-FCAW fill with matching 9Cr-2W consumables, 200–250 °C preheat, interpass ≤300 °C, no interruption below preheat, mandatory PWHT 750–780 °C with careful hold time; watch Type IV cracking in the fine-grain HAZ and keep Ni+Mn low in filler.
Can P92 be formed, bent or molded?
Hot form at 1050–1150 °C followed by a full re-normalize and temper; cold bending is limited and any cold strain above a few percent should be re-heat-treated to restore creep strength.
What surface finishes work on P92?
Not stainless — protect with high-temperature aluminium/silicone paint, aluminizing or Cr-diffusion coating for steam-side oxidation and shot-blast/pickle before coating; anodizing is not applicable.
P92 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.07 – 0.13 | 0.1 |
| Si | ≤ 0.5 | 0.25 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.01 | 0 |
| Cr | 8.5 – 9.5 | 9 |
| W | 1.5 – 2 | 1.8 |
| Mo | 0.3 – 0.6 | 0.5 |
| V | 0.15 – 0.25 | 0.2 |
| Nb | 0.04 – 0.09 | 0.06 |
| N | 0.03 – 0.07 | 0.05 |
| B | 0 – 0.01 | 0 |
| Ni | ≤ 0.4 | 0.2 |
| Al | ≤ 0.02 | 0.01 |
| Ti | ≤ 0.01 | — |
| Zr | ≤ 0.01 | — |
| Fe | balance | — |
P92 N&T — frequently asked
What is P92 N&T used for?
P92 N&T is typically used for ultra-supercritical main steam piping, hot reheat piping, boiler headers, high-temperature valve bodies, thick-wall forged fittings and superheater outlet tubing. In short: premium high-temp pipe.
What is the yield strength of P92 N&T?
P92 N&T has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is P92 N&T easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the N&T (≤250 HB) or annealed condition with rigid setups, coated carbide, moderate speed and heavy feed; the fine MX carbonitrides are abrasive and work-hardening is noticeable.
Can P92 N&T be welded?
With care — weldability is rated fair (40/100). GTAW root / SMAW-FCAW fill with matching 9Cr-2W consumables, 200–250 °C preheat, interpass ≤300 °C, no interruption below preheat, mandatory PWHT 750–780 °C with careful hold time; watch Type IV cracking in the fine-grain HAZ and keep Ni+Mn low in filler.
What surface finishes work on P92 N&T?
Not stainless — protect with high-temperature aluminium/silicone paint, aluminizing or Cr-diffusion coating for steam-side oxidation and shot-blast/pickle before coating; anodizing is not applicable.
Can P92 N&T be formed, bent or molded?
Hot form at 1050–1150 °C followed by a full re-normalize and temper; cold bending is limited and any cold strain above a few percent should be re-heat-treated to restore creep strength.
What is the maximum service temperature of P92 N&T?
P92 N&T is rated for continuous use to about 620°C (1,148 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in P92 N&T?
Yes — P92 N&T is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (Grade P92) — ASTM International (2022)
- ASME BPVC Section II Part A, SA-335 / SA-182 F92 — ASME (2023)
- EN 10216-2 — Seamless steel tubes for pressure purposes, X10CrWMoVNb9-2 (1.4901) — CEN (2020)
- GB/T 5310 — (10Cr9MoW2VNbBN) — SAC (2017)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- VdTÜV-Werkstoffblatt 552 — X10CrWMoVNb9-2 physical and elevated-temperature data — VdTÜV (2015)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.