Steel 12Ni14-QT (Quenched and tempered)
Heat-treated state
EN 12Ni14
Pick when higher yield strength and section-through toughness are needed in thick forgings, shafts, gears and pins.
Values for the QT condition
Other 12Ni14 tempers and conditions
12Ni14 is listed in 5 conditions; see the grade overview at 12Ni14.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Machining/cold-forming condition for bar and forging stock before final normalising or quench-and-temper. | 300 | 470 | 30 | 140 HB | 6.8 % IACS |
Hot rolled | Mill-finish bar and billet bought as feedstock for re-forging or full heat treatment; low-temperature toughness is not guaranteed in this state. | 380 | 560 | 24 | 175 HB | 6.6 % IACS |
NDefault Normalized | Standard delivery condition for EN 10028-4 plate and tube: best balance of −100 °C toughness, weldability and 355 MPa minimum yield. | 385 | 540 | 26 | 165 HB | — |
Normalized and tempered | Choose for heavier plate and forgings where a tempering cycle is used to level out hardness and maximise low-temperature Charpy energy. | 390 | 530 | 27 | 160 HB | — |
QTThis page Quenched and tempered | Pick when higher yield strength and section-through toughness are needed in thick forgings, shafts, gears and pins. | 480 | 620 | 23 | 14 HRC | — |
What is 12Ni14-QT?
12Ni14-QT is 12Ni14 heat treated to QT — pick when higher yield strength and section-through toughness are needed in thick forgings, shafts, gears and pins. 12Ni14-QT has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 59% of steel grades. Elongation at break is 23% and the elastic modulus is 206 GPa (29.9 Msi). 12Ni14-QT 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; QT is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
Limitations
- Low electrical conductivity — 6.6 % IACS, worse than 76% of steel grades
12Ni14-QT properties
Typical room-temperature values for 12Ni14-QT; 11 are specific to this condition. Other listed values are 12Ni14 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
12Ni14-QT 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).
Mechanical15
12Ni14-QT has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 59% of steel grades. Elongation at break is 23% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
12Ni14-QT is rated for continuous service to 350°C (662 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
12Ni14-QT conducts electricity at 6.6 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 12Ni14-QT takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability8
12Ni14-QT's machinability is fair (50/100, worse than 53% of steel grades); weldability very good (70/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 12Ni14-QT
Is 12Ni14 easy to machine?
Machines like a medium-carbon alloy steel at ~60 % of 1212; use sharp positive geometry and rigid setups because the nickel-bearing ferrite is gummy at low speeds.
Can 12Ni14 be welded?
Readily weldable with matching 3.5 Ni or Ni-base consumables, low hydrogen, preheat ~100 °C on thick section and controlled interpass to keep −100 °C Charpy values.
Can 12Ni14 be formed, bent or molded?
Good cold formability in N or A condition (bend radius ≈2–3 t); hot form 850–1100 °C and re-normalise afterwards to restore toughness.
What surface finishes work on 12Ni14?
Not corrosion resistant — shot blast then paint, metallise, hot-dip galvanise or zinc/nickel plate; phosphating suits gears and pins.
12Ni14 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 |
|---|---|---|
| CEN 10028-4 ladle analysis | ≤ 0.15 | 0.12 |
| Si | ≤ 0.35 | 0.25 |
| Mn | 0.3 – 0.8 | 0.55 |
| P | ≤ 0.02 | 0.01 |
| Slow S for through-thickness toughness | ≤ 0.01 | 0 |
| Nigives −100 °C toughness | 3.25 – 3.75 | 3.5 |
| Crresidual | ≤ 0.3 | 0.1 |
| Moresidual | ≤ 0.1 | 0.04 |
| Curesidual | ≤ 0.3 | 0.1 |
| Altotal Al, grain refining | ≥ 0.02 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| Fe | balance | — |
12Ni14-QT — frequently asked
What is 12Ni14-QT used for?
12Ni14-QT is typically used for gears, shafts and case-hardened components. In short: nickel steel for cold toughness; tough core case-hardening grade; weldable low-alloy steel.
What is the yield strength of 12Ni14-QT?
12Ni14-QT has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 620 MPa (89.9 ksi) — stronger than 59% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 12Ni14-QT easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines like a medium-carbon alloy steel at ~60 % of 1212; use sharp positive geometry and rigid setups because the nickel-bearing ferrite is gummy at low speeds.
Can 12Ni14-QT be welded?
Yes — weldability is rated very good (70/100). Readily weldable with matching 3.5 Ni or Ni-base consumables, low hydrogen, preheat ~100 °C on thick section and controlled interpass to keep −100 °C Charpy values.
What surface finishes work on 12Ni14-QT?
Not corrosion resistant — shot blast then paint, metallise, hot-dip galvanise or zinc/nickel plate; phosphating suits gears and pins.
Can 12Ni14-QT be formed, bent or molded?
Good cold formability in N or A condition (bend radius ≈2–3 t); hot form 850–1100 °C and re-normalise afterwards to restore toughness.
What is the maximum service temperature of 12Ni14-QT?
12Ni14-QT is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 12Ni14-N and 12Ni14-QT?
N is the default condition — standard delivery condition for EN 10028-4 plate and tube: best balance of −100 °C toughness, weldability and 355 MPa minimum yield. QT: pick when higher yield strength and section-through toughness are needed in thick forgings, shafts, gears and pins. Yield strength is 385 MPa in N versus 480 MPa in QT.
Sources
- EN 10028-4 — Flat products of steels for pressure purposes, Part 4: Nickel alloy steels with specified low-temperature properties — CEN (2017)
- EN 10222-3 — Steel forgings for pressure purposes: Nickel steels with specified low temperature properties — CEN (2017)
- ASTM A203/A203M — Pressure Vessel Plates, Alloy Steel, Nickel — ASTM (2019)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 3.5 % Ni cryogenic pressure vessel plate datasheets (1.5637 / A203 Gr. D-E) — European plate mills (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.