Steel A182 F911-AF (As-Forged)
Finish state
ASTM A182 F911 · UNS K91061
Rough forging supplied before normalizing/tempering — only for further heat treatment and machining allowance.
Values for the AF condition
Other A182 F911 tempers and conditions
A182 F911 is listed in 5 conditions; see the grade overview at A182 F911.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Soft condition used to ease heavy machining of large forgings before the final normalize-and-temper cycle. | 380 | 600 | 26 | 185 HB | — |
N&T double-tempered | Second temper used after weld repair or when a softer, tougher forging with guaranteed ≤ 248 HB is specified. | 480 | 665 | 24 | 15 HRC | 2.9 % IACS |
N+TDefault Normalized and tempered | Standard delivery condition for all A182 F911 flanges, valve bodies and fittings; gives the code-qualified creep strength. | 510 | 700 | 22 | 20 HRC | — |
Quenched and tempered | Accelerated/liquid quench used on thick valve bodies and large flanges to guarantee full martensite through-section before tempering. | 540 | 730 | 21 | 22 HRC | 2.9 % IACS |
AFThis page As-Forged | Rough forging supplied before normalizing/tempering — only for further heat treatment and machining allowance. | 650 | 900 | 15 | 34 HRC | 2.8 % IACS |
What is A182 F911-AF?
A182 F911-AF is A182 F911 supplied in the AF condition — rough forging supplied before normalizing/tempering — only for further heat treatment and machining allowance. A182 F911-AF has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 79% of steel grades. Elongation at break is 15% and the elastic modulus is 215 GPa (31.2 Msi). A182 F911-AF has a density of 7.77 g/cm³ (0.281 lb/in³), lighter than 92% of steel grades. It melts at 1,420°C (2,588 °F). N+T is the default condition FabDigit quotes; AF is available on request or by drawing note.
Advantages
- Good corrosion resistance — 30/100, better than 95% of steel grades
- High strength — 650 MPa (94.3 ksi), better than 79% of steel grades
Limitations
- Limited service temperature — 0°C (32 °F), worse than 100% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
- Low electrical conductivity — 2.8 % IACS, worse than 94% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Poor heat conductor — 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades
A182 F911-AF properties
Typical room-temperature values for A182 F911-AF; 22 are specific to this condition. Other listed values are A182 F911 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A182 F911-AF has a density of 7.77 g/cm³ (0.281 lb/in³), lighter than 92% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
A182 F911-AF has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 79% of steel grades. Elongation at break is 15% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
A182 F911-AF is rated for continuous service to 0°C (32 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 10.9 µm/m·K (6.06 µin/in·°F).
Electrical3
A182 F911-AF conducts electricity at 2.8 % IACS, worse than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of A182 F911-AF takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
A182 F911-AF's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (20/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A182 F911-AF
Is A182 F911 easy to machine?
Machine in the annealed or freshly tempered state with rigid setups, sharp coated carbide and generous coolant; the V/Nb carbonitrides are abrasive and work-hardening is noticeable at low feeds.
Can A182 F911 be welded?
GTAW root + SMAW/SAW fill with matching 9Cr-1Mo-W-V consumables, preheat/interpass 200–300 °C, cool to ~100 °C before mandatory PWHT at 750–770 °C; avoid over-temper and control Type IV HAZ creep damage.
Can A182 F911 be formed, bent or molded?
Hot forge from about 1150–1200 °C, finish above 900 °C, then always re-normalize and temper; cold forming is essentially limited to light straightening.
What surface finishes work on A182 F911?
No anodizing; use shot blast + high-temperature aluminium or silicone paint, or aluminide/thermal-spray coatings for steam-side oxidation and outdoor storage protection.
A182 F911 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 | 0.09 – 0.13 | 0.11 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.02 | — |
| S | ≤ 0.01 | — |
| Si | 0.1 – 0.5 | 0.25 |
| Cr | 8.5 – 9.5 | 9 |
| Mo | 0.9 – 1.1 | 1 |
| Wtungsten strengthening distinguishes 911 from Grade 91 | 0.9 – 1.1 | 1 |
| V | 0.18 – 0.25 | 0.21 |
| NbCb | 0.06 – 0.1 | 0.07 |
| N | 0.04 – 0.09 | 0.06 |
| B | 3×10⁻⁴ – 0.01 | 0 |
| Ni | ≤ 0.4 | — |
| Al | ≤ 0.02 | — |
| Ti | ≤ 0.01 | — |
| Zr | ≤ 0.01 | — |
| Fe | balance | — |
A182 F911-AF — frequently asked
What is A182 F911-AF used for?
A182 F911-AF is typically used for power plant steam header flanges, valve bodies for high-temperature steam and reactor internals. In short: creep-strength 9Cr forging grade; 620 °C steam service; mandatory PWHT after welding.
What is the yield strength of A182 F911-AF?
A182 F911-AF has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A182 F911-AF easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine in the annealed or freshly tempered state with rigid setups, sharp coated carbide and generous coolant; the V/Nb carbonitrides are abrasive and work-hardening is noticeable at low feeds.
Can A182 F911-AF be welded?
Not readily — weldability is rated poor (20/100). GTAW root + SMAW/SAW fill with matching 9Cr-1Mo-W-V consumables, preheat/interpass 200–300 °C, cool to ~100 °C before mandatory PWHT at 750–770 °C; avoid over-temper and control Type IV HAZ creep damage.
What surface finishes work on A182 F911-AF?
No anodizing; use shot blast + high-temperature aluminium or silicone paint, or aluminide/thermal-spray coatings for steam-side oxidation and outdoor storage protection.
Can A182 F911-AF be formed, bent or molded?
Hot forge from about 1150–1200 °C, finish above 900 °C, then always re-normalize and temper; cold forming is essentially limited to light straightening.
What is the maximum service temperature of A182 F911-AF?
A182 F911-AF is rated for continuous use to about 0°C (32 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A182 F911 N+T and A182 F911-AF?
N+T is the default condition — standard delivery condition for all A182 F911 flanges, valve bodies and fittings; gives the code-qualified creep strength. AF: rough forging supplied before normalizing/tempering — only for further heat treatment and machining allowance. Yield strength is 510 MPa in N+T versus 650 MPa in AF.
Sources
- ASTM A182/A182M — Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Fittings, Valves and Parts for High-Temperature Service (Grade F911) — ASTM International (2022)
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (Grade P911) — ASTM International (2022)
- EN 10216-2 — Seamless steel tubes for pressure purposes, X11CrMoWVNb9-1-1 (1.4905) — CEN (2020)
- ECCC Data Sheet — Creep rupture data for E911 (9Cr-1Mo-1W-V-Nb) — European Creep Collaborative Committee (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.