Steel A182 F11 Cl.1 NT-CL2
Heat-treated state
ASTM A182 F11 Cl.1 · UNS K11597
NT-CL2 = class 2
Pick when the piping class calls for the 485 MPa / 275 MPa strength grade of F11 (most common F11 class in refinery valves and fittings).
Values for the NT-CL2 condition
Other A182 F11 Cl.1 tempers and conditions
A182 F11 Cl.1 is listed in 4 conditions; see the grade overview at A182 F11 Cl.1.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard supply condition for F11 Cl.1 forgings, flanges and fittings where maximum weldability/softness (≤121 HB) is wanted and only the 415 MPa strength class is required. | 275 | 480 | 30 | 115 HB | — |
A335 P11 pipe | Choose when the same 1.25Cr-0.5Mo chemistry is bought as seamless high-temperature piping rather than forgings. | 290 | 490 | 30 | 145 HB | 7.8 % IACS |
NT-CL2This page Class 2 | Pick when the piping class calls for the 485 MPa / 275 MPa strength grade of F11 (most common F11 class in refinery valves and fittings). | 380 | 550 | 25 | 170 HB | — |
Class 3 | Used where 515 MPa / 310 MPa minimums are specified for heavy-wall F11 forgings; hardness still capped at 207 HB for wet-H2S service. | 415 | 580 | 24 | 180 HB | — |
What is A182 F11 Cl.1 NT-CL2?
A182 F11 Cl.1 NT-CL2 is A182 F11 Cl.1 heat treated to NT-CL2 — pick when the piping class calls for the 485 MPa / 275 MPa strength grade of F11 (most common F11 class in refinery valves and fittings). A182 F11 Cl.1 NT-CL2 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 68% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi). A182 F11 Cl.1 NT-CL2 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,450°C (2,642 °F). ANN is the default condition FabDigit quotes; NT-CL2 is available on request or by drawing note.
Advantages
- High service temperature — 580°C (1,076 °F), better than 97% of steel grades
- Tough — resists crack growth — 150 MPa·√m (136.5 ksi·√in), better than 96% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
A182 F11 Cl.1 NT-CL2 properties
Typical room-temperature values for A182 F11 Cl.1 NT-CL2; 12 are specific to this condition. Other listed values are A182 F11 Cl.1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A182 F11 Cl.1 NT-CL2 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
A182 F11 Cl.1 NT-CL2 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 68% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A182 F11 Cl.1 NT-CL2 is rated for continuous service to 580°C (1,076 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
A182 F11 Cl.1 NT-CL2 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of A182 F11 Cl.1 NT-CL2 takes about 31 MJ of energy and emits 2.2 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
A182 F11 Cl.1 NT-CL2's machinability is fair (52/100, better than 52% of steel grades); weldability fair (52/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A182 F11 Cl.1 NT-CL2
Is A182 F11 Cl.1 easy to machine?
Annealed Cl.1 machines readily at ~60 % of AISI 1212 with carbide or HSS tooling; low hardness gives gummy chips, so use positive rake, ample coolant and higher feeds.
Can A182 F11 Cl.1 be welded?
P-No.4 material: weld with matching E/ER 80S-B2 (or B2L) consumables, preheat 150–250 °C, interpass ≤315 °C and PWHT 700–760 °C to restore toughness and avoid hard HAZ.
Can A182 F11 Cl.1 be formed, bent or molded?
Hot forge at 1050–1200 °C, finish above 900 °C, then full anneal (~900 °C, furnace cool) for Cl.1; cold bending is possible but limited by 1.25Cr-0.5Mo work hardening.
What surface finishes work on A182 F11 Cl.1?
No anodizing; protect with shop primer, phosphating or aluminized/painted systems for atmospheric service, and use high-temperature coatings or insulation under hot piping to limit CUI.
A182 F11 Cl.1 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 | 0.05 – 0.15 | 0.12 |
| Mn | 0.3 – 0.6 | 0.45 |
| Si | 0.5 – 1 | 0.7 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 1 – 1.5 | 1.25 |
| Mo | 0.44 – 0.65 | 0.55 |
| Fe | balance | — |
A182 F11 Cl.1 NT-CL2 — frequently asked
What is A182 F11 Cl.1 NT-CL2 used for?
A182 F11 Cl.1 NT-CL2 is typically used for high-temperature flanges, valve bodies and refinery piping fittings. In short: softest 1.25Cr-0.5Mo forging class; creep service to 580 °C; easier machining than Cl.2.
What is the yield strength of A182 F11 Cl.1 NT-CL2?
A182 F11 Cl.1 NT-CL2 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A182 F11 Cl.1 NT-CL2 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Annealed Cl.1 machines readily at ~60 % of AISI 1212 with carbide or HSS tooling; low hardness gives gummy chips, so use positive rake, ample coolant and higher feeds.
Can A182 F11 Cl.1 NT-CL2 be welded?
With care — weldability is rated fair (52/100). P-No.4 material: weld with matching E/ER 80S-B2 (or B2L) consumables, preheat 150–250 °C, interpass ≤315 °C and PWHT 700–760 °C to restore toughness and avoid hard HAZ.
What surface finishes work on A182 F11 Cl.1 NT-CL2?
No anodizing; protect with shop primer, phosphating or aluminized/painted systems for atmospheric service, and use high-temperature coatings or insulation under hot piping to limit CUI.
Can A182 F11 Cl.1 NT-CL2 be formed, bent or molded?
Hot forge at 1050–1200 °C, finish above 900 °C, then full anneal (~900 °C, furnace cool) for Cl.1; cold bending is possible but limited by 1.25Cr-0.5Mo work hardening.
What is the maximum service temperature of A182 F11 Cl.1 NT-CL2?
A182 F11 Cl.1 NT-CL2 is rated for continuous use to about 580°C (1,076 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A182 F11 Cl.1-ANN and A182 F11 Cl.1 NT-CL3?
ANN is the default condition — standard supply condition for F11 Cl.1 forgings, flanges and fittings where maximum weldability/softness (≤121 HB) is wanted and only the 415 MPa strength class is required. NT-CL3: used where 515 MPa / 310 MPa minimums are specified for heavy-wall F11 forgings; hardness still capped at 207 HB for wet-H2S service. Yield strength is 275 MPa in ANN versus 415 MPa in NT-CL3.
Sources
- ASTM A182/A182M — Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Fittings, Valves and Parts for High-Temperature Service — ASTM International (2023)
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (P11) — ASTM International (2023)
- ASME BPVC Section II Part D — Materials, Properties (Metric) — ASME (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — API (2016)
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.