Steel 16Mo3-NT
Heat-treated state
EN 16Mo3
Used for heavy plate and forgings where tempering after normalizing improves toughness uniformity through thickness.
Values for the NT condition
Other 16Mo3 tempers and conditions
16Mo3 is listed in 7 conditions; see the grade overview at 16Mo3.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition for deep cold forming, heavy machining or cold-drawn tube intermediate stage. | 265 | 450 | 30 | 135 HB | 7.9 % IACS |
Stress relieved | Ordered when the vessel will see post-weld heat treatment; properties are certified after the simulated PWHT cycle (~620–680 °C). | 295 | 470 | 27 | 145 HB | 7.8 % IACS |
NTThis page normalized and tempered | Used for heavy plate and forgings where tempering after normalizing improves toughness uniformity through thickness. | 300 | 475 | 27 | 145 HB | 7.8 % IACS |
NDefault Normalized | Standard stocked condition for boiler plate, tube and pipe; fine-grained ferrite-pearlite with guaranteed elevated-temperature proof stress. | 310 | 490 | 26 | 150 HB | 7.8 % IACS |
as-rolled (hot rolled, no subsequent heat treatment) | Economy condition for thin plate/strip where normalizing is not required by the code; properties vary more with thickness. | 315 | 500 | 24 | 155 HB | 7.8 % IACS |
Quenched and tempered | Chosen for thick forgings and flanges (EN 10222-2) needing higher yield strength and low-temperature toughness. | 400 | 560 | 22 | 178 HB | 7.6 % IACS |
cold drawn (seamless tube / bar, as-drawn) | Cold-drawn tube or bar for tight tolerance and higher strength; must be normalized before use above design creep temperatures. | 450 | 560 | 13 | 175 HB | 7.8 % IACS |
What is 16Mo3-NT?
16Mo3-NT is 16Mo3 heat treated to NT — used for heavy plate and forgings where tempering after normalizing improves toughness uniformity through thickness. 16Mo3-NT has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 475 MPa (68.9 ksi) — weaker than 86% of steel grades. Elongation at break is 27% and the elastic modulus is 212 GPa (30.7 Msi). 16Mo3-NT 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). N is the default condition FabDigit quotes; NT is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
- Forms and bends easily — 67/100, better than 83% of steel grades
Limitations
- Low strength — 300 MPa (43.5 ksi), worse than 86% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
16Mo3-NT properties
Typical room-temperature values for 16Mo3-NT; 22 are specific to this condition. Other listed values are 16Mo3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
16Mo3-NT 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
16Mo3-NT has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 475 MPa (68.9 ksi) — weaker than 86% of steel grades. Elongation at break is 27% and the elastic modulus is 212 GPa (30.7 Msi).
Thermal6
16Mo3-NT is rated for continuous service to 500°C (932 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
16Mo3-NT conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 16Mo3-NT takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
16Mo3-NT's machinability is good (62/100, better than 89% of steel grades); weldability very good (80/100); formability good (67/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 16Mo3-NT
Is 16Mo3 easy to machine?
Machines like a medium-carbon steel — carbide tooling, ~120–180 m/min turning speed in the normalized state; Mo gives slightly gummier chips than plain C-Mn steel.
Can 16Mo3 be welded?
Good weldability with SMAW/SAW/GTAW using matching 1%Mo consumables (E7018-A1, ER80S-G); preheat 100–200 °C for t > 20 mm and PWHT at 620–680 °C to restore HAZ toughness.
Can 16Mo3 be formed, bent or molded?
Hot form at 900–1050 °C followed by re-normalizing; cold bending is practical to about 3t radius in annealed or normalized plate.
What surface finishes work on 16Mo3?
No anodizing; protect by shot blasting plus epoxy/high-temperature silicone paint, aluminizing or thermal insulation, and control corrosion under insulation.
16Mo3 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 | 0.12 – 0.2 | 0.16 |
| Si | ≤ 0.35 | 0.25 |
| Mn | 0.4 – 0.9 | 0.65 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.01 | 0.01 |
| Mocreep-strengthening addition | 0.25 – 0.35 | 0.3 |
| Crresidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.3 | 0.1 |
| Curesidual | ≤ 0.3 | 0.1 |
| Nb | ≤ 0.01 | — |
| Ti | ≤ 0.03 | — |
| Fe | balance | — |
16Mo3-NT — frequently asked
What is 16Mo3-NT used for?
16Mo3-NT is typically used for boiler tubes, pressure vessels, piping and heat exchangers. In short: baseline C-Mo boiler steel; best weldability in family; service to about 450 °C.
What is the yield strength of 16Mo3-NT?
16Mo3-NT has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 475 MPa (68.9 ksi) — weaker than 86% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 16Mo3-NT easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines like a medium-carbon steel — carbide tooling, ~120–180 m/min turning speed in the normalized state; Mo gives slightly gummier chips than plain C-Mn steel.
Can 16Mo3-NT be welded?
Yes — weldability is rated very good (80/100). Good weldability with SMAW/SAW/GTAW using matching 1%Mo consumables (E7018-A1, ER80S-G); preheat 100–200 °C for t > 20 mm and PWHT at 620–680 °C to restore HAZ toughness.
What surface finishes work on 16Mo3-NT?
No anodizing; protect by shot blasting plus epoxy/high-temperature silicone paint, aluminizing or thermal insulation, and control corrosion under insulation.
Can 16Mo3-NT be formed, bent or molded?
Hot form at 900–1050 °C followed by re-normalizing; cold bending is practical to about 3t radius in annealed or normalized plate.
What is the maximum service temperature of 16Mo3-NT?
16Mo3-NT is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 16Mo3-N and 16Mo3-C?
N is the default condition — standard stocked condition for boiler plate, tube and pipe; fine-grained ferrite-pearlite with guaranteed elevated-temperature proof stress. C: cold-drawn tube or bar for tight tolerance and higher strength; must be normalized before use above design creep temperatures. Yield strength is 310 MPa in N versus 450 MPa in C.
Sources
- EN 10028-2 — Flat products of steels for pressure purposes, Part 2: Non-alloy and alloy steels with specified elevated temperature properties — CEN (2017)
- EN 10216-2 — Seamless steel tubes for pressure purposes, Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties — CEN (2020)
- EN 10222-2 — Steel forgings for pressure purposes, Part 2: Ferritic and martensitic steels with specified elevated temperature properties — CEN (2017)
- ASME SA-204 / ASTM A204 Grade A — Pressure Vessel Plates, Alloy Steel, Molybdenum — ASTM / ASME (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Boiler and pressure vessel steel 16Mo3 data sheet — Dillinger / Voestalpine (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.