Steel 12CrMo9-10 +NT (Normalized and tempered)
Heat-treated state · default condition
EN 12CrMo9-10 · ASTM A335 P22
Standard delivery condition for EN 10216-2 seamless tube and EN 10028-2 plate; best balance of creep strength and toughness for steam service.
Values for the +NT condition
Other 12CrMo9-10 tempers and conditions
12CrMo9-10 is listed in 6 conditions; see the grade overview at 12CrMo9-10.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum machinability/cold-forming of tube and bar before final normalize-and-temper of the fabricated part. | 250 | 470 | 28 | 140 HB | 7.9 % IACS |
+NTDefaultThis page Normalized and tempered | Standard delivery condition for EN 10216-2 seamless tube and EN 10028-2 plate; best balance of creep strength and toughness for steam service. | 320 | 540 | 24 | 160 HB | — |
Hot rolled | Mill as-rolled semi-finished stock bought for re-forging or for parts that will be fully heat treated after machining. | 340 | 570 | 20 | 175 HB | 7.8 % IACS |
Normalized | Intermediate condition for plate/pipe that will still see PWHT or a subsequent temper; slightly higher strength but lower toughness than +NT. | 370 | 590 | 21 | 180 HB | 7.8 % IACS |
Quenched and tempered | Used for heavy forgings, valve bodies and thick-wall vessel shells (EN 10222-2 / EN 10250-2) where through-thickness strength and toughness are needed. | 400 | 610 | 20 | 12 HRC | — |
Cold drawn | Small-diameter precision tube and bar; higher strength and tight tolerance, but requires stress-relief/normalize-temper before high-temperature service. | 500 | 640 | 14 | 205 HB | 7.7 % IACS |
What is 12CrMo9-10 +NT?
12CrMo9-10 +NT is 12CrMo9-10 heat treated to +NT — standard delivery condition for EN 10216-2 seamless tube and EN 10028-2 plate; best balance of creep strength and toughness for steam service. 12CrMo9-10 +NT has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 81% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi). 12CrMo9-10 +NT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Advantages
- High service temperature — 565°C (1,049 °F), better than 96% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
Limitations
- Low strength — 320 MPa (46.4 ksi), worse than 81% of steel grades
12CrMo9-10 +NT properties
Typical room-temperature values for 12CrMo9-10 +NT; 11 are specific to this condition. Other listed values are 12CrMo9-10 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
12CrMo9-10 +NT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical16
12CrMo9-10 +NT has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 81% of steel grades. Elongation at break is 24% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
12CrMo9-10 +NT is rated for continuous service to 565°C (1,049 °F). It conducts heat at 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 71% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
12CrMo9-10 +NT 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 12CrMo9-10 +NT takes about 32 MJ of energy and emits 2.2 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability8
12CrMo9-10 +NT's machinability is good (55/100, better than 62% of steel grades); weldability good (55/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 12CrMo9-10 +NT
Is 12CrMo9-10 easy to machine?
Machines like annealed 4130 at ~60 % of 1212 — moderate speeds, rigid setups, positive-rake carbide and generous coolant to avoid work hardening and gummy chips.
Can 12CrMo9-10 be welded?
Weld with matching 2.25Cr-1Mo consumables (E9018-B3 / ER90S-B3), preheat 200–250 °C, interpass ≤350 °C, low-hydrogen practice, and mandatory PWHT 690–730 °C; hold hardness ≤225 HB in wet-H2S service.
Can 12CrMo9-10 be formed, bent or molded?
Hot bend/form at 900–1050 °C followed by normalize-and-temper; cold bending of tube is possible with generous radii but needs stress relief before high-temperature service.
What surface finishes work on 12CrMo9-10?
Not anodizable; protect with phosphate + high-temperature aluminium/silicone paint, aluminizing or thermal insulation — bare surfaces scale above ~570 °C and rust in humid storage.
12CrMo9-10 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 – 0.15 | 0.12 |
| Si | ≤ 0.5 | 0.25 |
| MnEN 10216-2 range; A335 P22 0.30–0.60 | 0.4 – 0.8 | 0.55 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.01 | 0.01 |
| Cr | 2 – 2.5 | 2.25 |
| Mo | 0.9 – 1.1 | 1 |
| Niresidual | ≤ 0.3 | — |
| Fe | balance | — |
12CrMo9-10 +NT — frequently asked
What is 12CrMo9-10 +NT used for?
12CrMo9-10 +NT is typically used for boiler tubes, steam piping and pressure vessels. In short: workhorse P22 pipe steel; 565 °C creep service; weldable with PWHT.
What is the yield strength of 12CrMo9-10 +NT?
12CrMo9-10 +NT has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 81% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 12CrMo9-10 +NT easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like annealed 4130 at ~60 % of 1212 — moderate speeds, rigid setups, positive-rake carbide and generous coolant to avoid work hardening and gummy chips.
Can 12CrMo9-10 +NT be welded?
Yes — weldability is rated good (55/100). Weld with matching 2.25Cr-1Mo consumables (E9018-B3 / ER90S-B3), preheat 200–250 °C, interpass ≤350 °C, low-hydrogen practice, and mandatory PWHT 690–730 °C; hold hardness ≤225 HB in wet-H2S service.
What surface finishes work on 12CrMo9-10 +NT?
Not anodizable; protect with phosphate + high-temperature aluminium/silicone paint, aluminizing or thermal insulation — bare surfaces scale above ~570 °C and rust in humid storage.
Can 12CrMo9-10 +NT be formed, bent or molded?
Hot bend/form at 900–1050 °C followed by normalize-and-temper; cold bending of tube is possible with generous radii but needs stress relief before high-temperature service.
What is the maximum service temperature of 12CrMo9-10 +NT?
12CrMo9-10 +NT is rated for continuous use to about 565°C (1,049 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 12CrMo9-10 +NT and 12CrMo9-10-CD?
+NT is the default condition — standard delivery condition for EN 10216-2 seamless tube and EN 10028-2 plate; best balance of creep strength and toughness for steam service. CD: small-diameter precision tube and bar; higher strength and tight tolerance, but requires stress-relief/normalize-temper before high-temperature service. Yield strength is 320 MPa in +NT versus 500 MPa in CD.
Sources
- EN 10216-2 Seamless steel tubes for pressure purposes — alloy steel with specified elevated temperature properties — CEN (2020)
- EN 10028-2 Flat products for pressure purposes — alloy steels with specified elevated temperature properties — CEN (2017)
- EN 10222-2 Steel forgings for pressure purposes — ferritic and martensitic steels — CEN (2021)
- ASTM A335/A335M Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (Grade P22) — ASTM (2023)
- GB/T 5310 (12Cr2MoG) — SAC (2017)
- 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)
- Seamless Cr-Mo boiler tube datasheets (P22 / 10CrMo910) — Vallourec / Sandvik (2022)
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.