Steel A182 F122 N+T+PWHT
Heat-treated state
ASTM A182 F122 · UNS K91271
N+T+PWHT = normalized and tempered, then post-weld heat treated 740–780 °C
Condition of the finished welded assembly; slightly softer than the as-tempered forging and the basis for weldment creep assessment.
Values for the N+T+PWHT condition
Other A182 F122 tempers and conditions
A182 F122 is listed in 5 conditions; see the grade overview at A182 F122.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Subcritical/soft annealed (≈760–800 °C, slow cool) for machining or… | Non-code intermediate condition supplied for heavy machining or cold sizing; must be re-normalized and tempered before service. | 420 | 620 | 26 | 11 HRC | 3 % IACS |
N+T+PWHTThis page Normalized and tempered, then post-weld heat treated 740–780 °C | Condition of the finished welded assembly; slightly softer than the as-tempered forging and the basis for weldment creep assessment. | 460 | 655 | 24 | 15 HRC | 2.9 % IACS |
Normalized plus double temper | Used when maximum toughness and full hardness compliance (<250 HBW) are needed on thick sections or after repair welding. | 465 | 660 | 25 | 15 HRC | 2.9 % IACS |
N+TDefault Normalized and tempered | Standard supply condition for all ASTM A182 F122 forgings, flanges, valve bodies and fittings in USC steam service. | 490 | 690 | 23 | 18 HRC | — |
Austenitized 1040–1090 °C with accelerated (liquid/forced-air) cooling,… | Chosen for heavy-section forgings where air cooling cannot ensure full martensite through-thickness; gives the same tempered properties with better core uniformity. | 510 | 710 | 22 | 20 HRC | — |
What is A182 F122 N+T+PWHT?
A182 F122 N+T+PWHT is A182 F122 heat treated to N+T+PWHT — condition of the finished welded assembly; slightly softer than the as-tempered forging and the basis for weldment creep assessment. A182 F122 N+T+PWHT has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 55% of steel grades. Elongation at break is 24% and the elastic modulus is 213 GPa (30.9 Msi). A182 F122 N+T+PWHT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,420°C (2,588 °F). N+T is the default condition FabDigit quotes; N+T+PWHT 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 — 35/100, better than 97% of steel grades
- Tough — resists crack growth — 115 MPa·√m (104.7 ksi·√in), better than 77% of steel grades
Limitations
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
- Poor heat conductor — 26 W/m·K (15 BTU/hr·ft·°F), worse than 87% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
A182 F122 N+T+PWHT properties
Typical room-temperature values for A182 F122 N+T+PWHT; 23 are specific to this condition. Other listed values are A182 F122 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A182 F122 N+T+PWHT has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 93% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
A182 F122 N+T+PWHT has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 55% of steel grades. Elongation at break is 24% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal6
A182 F122 N+T+PWHT is rated for continuous service to 620°C (1,148 °F). It conducts heat at 26 W/m·K (15 BTU/hr·ft·°F), worse than 87% of steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
A182 F122 N+T+PWHT conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), better than 97% of steel grades.
Sustainability4
Producing a kilogram of A182 F122 N+T+PWHT takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
A182 F122 N+T+PWHT's machinability is fair (42/100, worse than 73% of steel grades); weldability fair (40/100); formability poor (26/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A182 F122 N+T+PWHT
Is A182 F122 easy to machine?
Machine in the tempered (≈215 HB) condition with rigid setups, coated carbide, moderate speed and heavy feed; the work-hardening martensite dulls edges so avoid dwelling and keep coolant flooded.
Can A182 F122 be welded?
Weld with matching 9-12Cr filler (e.g. W-modified E911/P122 consumables), 200–250 °C preheat, interpass ≤350 °C, hydrogen control, cool to ~100 °C before a mandatory 740–780 °C PWHT; expect Type IV creep weakness in the fine-grained HAZ.
Can A182 F122 be formed, bent or molded?
Hot forge 1150–950 °C and always re-normalize and temper afterwards; cold forming is essentially limited to minor straightening because of the low ductility and high springback.
What surface finishes work on A182 F122?
Not stainless — shot-blast plus preservation oil or paint for storage; for wet steam/water-side duty consider chromizing, aluminizing or a weld overlay rather than relying on the 11Cr base metal.
A182 F122 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 – 0.14 | 0.11 |
| Mn | ≤ 0.7 | 0.55 |
| P | ≤ 0.02 | — |
| S | ≤ 0.01 | — |
| Si | ≤ 0.5 | 0.25 |
| Ni | ≤ 0.5 | 0.25 |
| Cr | 10 – 11.5 | 10.8 |
| Mo | 0.25 – 0.6 | 0.4 |
| Wsolid-solution creep strengthener | 1.5 – 2.5 | 1.9 |
| Cufine Cu precipitates | 0.3 – 1.7 | 1 |
| V | 0.15 – 0.3 | 0.2 |
| NbCb in ASTM text | 0.04 – 0.1 | 0.06 |
| NMX nitride former | 0.04 – 0.1 | 0.06 |
| B | 5×10⁻⁴ – 0.01 | 0 |
| Alsoluble Al limited to protect N | ≤ 0.02 | — |
| Ti | ≤ 0.01 | — |
| Zr | ≤ 0.01 | — |
| Fe | balance | — |
A182 F122 N+T+PWHT — frequently asked
What is A182 F122 N+T+PWHT used for?
A182 F122 N+T+PWHT is typically used for ultra-supercritical boiler flanges, high-temperature steam headers and valve bodies. In short: highest creep strength here; 620 °C USC steam service; hardest to weld and machine.
What is the yield strength of A182 F122 N+T+PWHT?
A182 F122 N+T+PWHT has a typical yield strength of 460 MPa (66.7 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 55% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A182 F122 N+T+PWHT easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in the tempered (≈215 HB) condition with rigid setups, coated carbide, moderate speed and heavy feed; the work-hardening martensite dulls edges so avoid dwelling and keep coolant flooded.
Can A182 F122 N+T+PWHT be welded?
With care — weldability is rated fair (40/100). Weld with matching 9-12Cr filler (e.g. W-modified E911/P122 consumables), 200–250 °C preheat, interpass ≤350 °C, hydrogen control, cool to ~100 °C before a mandatory 740–780 °C PWHT; expect Type IV creep weakness in the fine-grained HAZ.
What surface finishes work on A182 F122 N+T+PWHT?
Not stainless — shot-blast plus preservation oil or paint for storage; for wet steam/water-side duty consider chromizing, aluminizing or a weld overlay rather than relying on the 11Cr base metal.
Can A182 F122 N+T+PWHT be formed, bent or molded?
Hot forge 1150–950 °C and always re-normalize and temper afterwards; cold forming is essentially limited to minor straightening because of the low ductility and high springback.
What is the maximum service temperature of A182 F122 N+T+PWHT?
A182 F122 N+T+PWHT 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.
What is the difference between A182 F122 N+T and A182 F122-SA?
N+T is the default condition — standard supply condition for all ASTM A182 F122 forgings, flanges, valve bodies and fittings in USC steam service. SA: non-code intermediate condition supplied for heavy machining or cold sizing; must be re-normalized and tempered before service. Yield strength is 490 MPa in N+T versus 420 MPa in SA.
Sources
- ASTM A182/A182M — Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Fittings, Valves and Parts (Grade F122) — ASTM International (2024)
- ASME BPVC Section II Part D — Allowable stresses and physical properties for 11Cr-2W-0.4Mo-1Cu-V-Nb (P122) — ASME (2023)
- ASTM A213/A335 Grades T122/P122 (companion tube and pipe grades) — ASTM International (2023)
- HCM12A (11Cr-2W-Cu-V-Nb) boiler steel technical data — Nippon Steel / Mitsubishi Heavy Industries (2015)
- NIMS Creep Data Sheet — high-Cr ferritic heat-resisting steels — National Institute for Materials Science, Japan (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
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.