Steel 11CrMo9-10 +A (Annealed)
Heat-treated state
EN 11CrMo9-10 · ASTM A182 F22
Softest condition, chosen for maximum machinability, deep cold sizing or when a low-hardness ferritic microstructure is specified.
Values for the +A condition
Other 11CrMo9-10 tempers and conditions
11CrMo9-10 is listed in 5 conditions; see the grade overview at 11CrMo9-10.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+AThis page Annealed | Softest condition, chosen for maximum machinability, deep cold sizing or when a low-hardness ferritic microstructure is specified. | 250 | 460 | 28 | 145 HB | — |
+NTDefault Normalized and tempered | Standard delivery condition for pressure forgings, plate and pipe (A182 F22 Cl.3 equivalent) — best balance of creep strength, toughness and weldability. | 360 | 580 | 22 | 175 HB | — |
Normalized | Intermediate stock condition (usually followed by tempering) giving a uniform bainitic/ferritic structure after forging. | 400 | 620 | 20 | 13 HRC | 7.8 % IACS |
+QT | Quenched-and-tempered with a capped hardness and controlled J/X-factor for wet H2S (sour) service flanges and valve bodies. | 440 | 620 | 22 | 19 HRC | 7.8 % IACS |
Quenched and tempered | Higher-strength condition for heavy-wall valve bodies and thick flanges where through-thickness yield strength and low-temperature toughness are critical. | 480 | 660 | 20 | 18 HRC | — |
What is 11CrMo9-10 +A?
11CrMo9-10 +A is 11CrMo9-10 heat treated to +A — softest condition, chosen for maximum machinability, deep cold sizing or when a low-hardness ferritic microstructure is specified. 11CrMo9-10 +A has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 94% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi). 11CrMo9-10 +A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). +NT is the default condition FabDigit quotes; +A is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 150 MPa·√m (136.5 ksi·√in), better than 96% of steel grades
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 94% of steel grades
11CrMo9-10 +A properties
Typical room-temperature values for 11CrMo9-10 +A; 15 are specific to this condition. Other listed values are 11CrMo9-10 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
11CrMo9-10 +A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
11CrMo9-10 +A has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 94% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
11CrMo9-10 +A is rated for continuous service to 550°C (1,022 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
11CrMo9-10 +A conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of 11CrMo9-10 +A takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability6
11CrMo9-10 +A's machinability is good (62/100, better than 89% of steel grades); weldability good (58/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 11CrMo9-10 +A
Is 11CrMo9-10 easy to machine?
Machines like 4140-class Cr-Mo at ~55 % of 1212; use rigid setups, coated carbide, 100–160 m/min in the +NT condition and expect higher tool wear after Q&T.
Can 11CrMo9-10 be welded?
Weld with matching 2.25Cr-1Mo consumables (E9018-B3 / ER90S-B3), preheat 200–250 °C, interpass ≤ 350 °C and PWHT 690–730 °C; control hydrogen and J/X factors to avoid reheat and temper embrittlement.
Can 11CrMo9-10 be formed, bent or molded?
Forge at 1050–1200 °C with slow cooling; cold forming is limited — bend or flange hot, then re-normalize and temper.
What surface finishes work on 11CrMo9-10?
Not corrosion resistant: shot-blast and apply high-temperature aluminium/silicone paint, metallize, or use stainless overlay/cladding on wetted surfaces; takes phosphate and electroless-nickel well.
11CrMo9-10 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 | 0.08 – 0.14 | 0.11 |
| Si | ≤ 0.5 | 0.25 |
| Mn | 0.4 – 0.8 | 0.6 |
| Plower limits often imposed to control temper embrittlement (J-factor) | ≤ 0.02 | 0.01 |
| S | ≤ 0.01 | 0.01 |
| Cr | 2 – 2.5 | 2.25 |
| Mo | 0.9 – 1.1 | 1 |
| Ni | ≤ 0.3 | 0.15 |
| Cu | ≤ 0.3 | 0.1 |
| Fe | balance | — |
11CrMo9-10 +A — frequently asked
What is 11CrMo9-10 +A used for?
11CrMo9-10 +A is typically used for forged flanges, valve bodies and pressure vessel forgings. In short: forging grade of P22; sour-service +QT option; 550 °C pressure forgings.
What is the yield strength of 11CrMo9-10 +A?
11CrMo9-10 +A has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 94% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 11CrMo9-10 +A easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines like 4140-class Cr-Mo at ~55 % of 1212; use rigid setups, coated carbide, 100–160 m/min in the +NT condition and expect higher tool wear after Q&T.
Can 11CrMo9-10 +A be welded?
Yes — weldability is rated good (58/100). Weld with matching 2.25Cr-1Mo consumables (E9018-B3 / ER90S-B3), preheat 200–250 °C, interpass ≤ 350 °C and PWHT 690–730 °C; control hydrogen and J/X factors to avoid reheat and temper embrittlement.
What surface finishes work on 11CrMo9-10 +A?
Not corrosion resistant: shot-blast and apply high-temperature aluminium/silicone paint, metallize, or use stainless overlay/cladding on wetted surfaces; takes phosphate and electroless-nickel well.
Can 11CrMo9-10 +A be formed, bent or molded?
Forge at 1050–1200 °C with slow cooling; cold forming is limited — bend or flange hot, then re-normalize and temper.
What is the maximum service temperature of 11CrMo9-10 +A?
11CrMo9-10 +A is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10222-2 — Steel forgings for pressure purposes, ferritic and martensitic steels with elevated temperature properties — CEN (2017)
- EN 10028-2 — Flat products of steels for pressure purposes, non-alloy and alloy steels with elevated temperature properties — CEN (2017)
- ASTM A182/A182M — Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Fittings, Valves and Parts (Grade F22) — ASTM (2022)
- ASME BPVC Section II Part D — Material Properties (2.25Cr-1Mo) — 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)
- 12Cr2Mo1 / 12Cr2Mo1R — Mysteel / 1688 (2025)
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.