Steel 15NiMn6 Q+T
Heat-treated state
EN 15NiMn6
Q+T = quenched and tempered
Use for heavy forgings, flanges and thick shells where higher yield strength and better through-thickness toughness are needed.
Values for the Q+T condition
Other 15NiMn6 tempers and conditions
15NiMn6 is listed in 6 conditions; see the grade overview at 15NiMn6.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Pick for maximum machinability and cold formability of bar/forging stock before final heat treatment. | 290 | 470 | 30 | 140 HB | — |
Normalized, tempered and stress-relieved / simulated PWHT | Ordered when the vessel will see a post-weld heat treatment and properties must be certified in the simulated PWHT condition. | 360 | 540 | 27 | 158 HB | 7.5 % IACS |
Hot rolled | Semi-finished bar, billet or forging blank supplied untreated; must be normalized or Q&T before pressure-retaining service. | 370 | 580 | 22 | 9 HRC | 7.5 % IACS |
Normalized | Standard delivery condition for plate where fine grain and uniform properties are enough without a separate tempering cycle. | 375 | 555 | 25 | 168 HB | — |
N+TDefault Normalized and tempered | Most commonly stocked pressure-vessel condition: guaranteed −80 °C Charpy values with good weldability. | 380 | 560 | 26 | 165 HB | — |
Q+TThis page Quenched and tempered | Use for heavy forgings, flanges and thick shells where higher yield strength and better through-thickness toughness are needed. | 470 | 640 | 23 | 17 HRC | — |
What is 15NiMn6 Q+T?
15NiMn6 Q+T is 15NiMn6 heat treated to Q+T — use for heavy forgings, flanges and thick shells where higher yield strength and better through-thickness toughness are needed. 15NiMn6 Q+T has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 57% of steel grades. Elongation at break is 23% and the elastic modulus is 210 GPa (30.5 Msi). 15NiMn6 Q+T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). N+T is the default condition FabDigit quotes; Q+T is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 145 MPa·√m (132 ksi·√in), better than 95% of steel grades
- Readily welded — 75/100, better than 76% of steel grades
Limitations
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
15NiMn6 Q+T properties
Typical room-temperature values for 15NiMn6 Q+T; 14 are specific to this condition. Other listed values are 15NiMn6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
15NiMn6 Q+T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
15NiMn6 Q+T has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 57% of steel grades. Elongation at break is 23% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
15NiMn6 Q+T is rated for continuous service to 350°C (662 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 62% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
15NiMn6 Q+T conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 15NiMn6 Q+T takes about 34 MJ of energy and emits 2.5 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
15NiMn6 Q+T's machinability is fair (48/100, worse than 57% of steel grades); weldability very good (75/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 15NiMn6 Q+T
Is 15NiMn6 easy to machine?
Machines like normalized C-Mn vessel steel — moderate speeds with coated carbide, positive rake and generous coolant to control gummy chips and built-up edge.
Can 15NiMn6 be welded?
Good weldability with low-hydrogen SMAW, SAW or FCAW using matching 1 % Ni consumables; preheat 100–150 °C on heavy sections, control heat input and PWHT at 530–600 °C to preserve −80 °C toughness.
Can 15NiMn6 be formed, bent or molded?
Hot form 850–1000 °C followed by re-normalizing; cold forming is possible but limit strain and re-heat-treat if cold deformation exceeds code limits to restore notch toughness.
What surface finishes work on 15NiMn6?
No anodizing; protect with blast-and-paint systems, zinc/aluminium metallising or Zn-Ni plating, and always use a vapour-tight insulation barrier in cryogenic service.
15NiMn6 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 |
|---|---|---|
| Cladle analysis; often 0.12–0.18 | ≤ 0.18 | 0.15 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.8 – 1.5 | 1.15 |
| P | ≤ 0.03 | 0.02 |
| Slow S for through-thickness toughness | ≤ 0.01 | 0.01 |
| Nikey element for low-temperature toughness | 1 – 1.5 | 1.25 |
| Crresidual | ≤ 0.3 | 0.1 |
| Moresidual | ≤ 0.1 | 0.03 |
| Curesidual | ≤ 0.3 | 0.1 |
| Vresidual | ≤ 0.05 | 0.01 |
| Nbgrain refining, optional | ≤ 0.05 | 0.02 |
| Altotal Al for fine-grain practice | ≥ 0.02 | 0.04 |
| Fe | balance | — |
15NiMn6 Q+T — frequently asked
What is 15NiMn6 Q+T used for?
15NiMn6 Q+T is typically used for pressure vessels, boiler components and low-temperature service equipment. In short: tough to −80 °C; 1 % Ni vessel steel; good code weldability.
What is the yield strength of 15NiMn6 Q+T?
15NiMn6 Q+T has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 15NiMn6 Q+T easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Machines like normalized C-Mn vessel steel — moderate speeds with coated carbide, positive rake and generous coolant to control gummy chips and built-up edge.
Can 15NiMn6 Q+T be welded?
Yes — weldability is rated very good (75/100). Good weldability with low-hydrogen SMAW, SAW or FCAW using matching 1 % Ni consumables; preheat 100–150 °C on heavy sections, control heat input and PWHT at 530–600 °C to preserve −80 °C toughness.
What surface finishes work on 15NiMn6 Q+T?
No anodizing; protect with blast-and-paint systems, zinc/aluminium metallising or Zn-Ni plating, and always use a vapour-tight insulation barrier in cryogenic service.
Can 15NiMn6 Q+T be formed, bent or molded?
Hot form 850–1000 °C followed by re-normalizing; cold forming is possible but limit strain and re-heat-treat if cold deformation exceeds code limits to restore notch toughness.
What is the maximum service temperature of 15NiMn6 Q+T?
15NiMn6 Q+T 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 15NiMn6 N+T and 15NiMn6-A?
N+T is the default condition — most commonly stocked pressure-vessel condition: guaranteed −80 °C Charpy values with good weldability. A: pick for maximum machinability and cold formability of bar/forging stock before final heat treatment. Yield strength is 380 MPa in N+T versus 290 MPa in A.
Sources
- EN 10028-4 — Flat products of steels for pressure purposes: nickel alloy steels with specified low temperature properties — CEN (2017)
- DIN 17280 — Tough steels for low temperature service (historic, 15NiMn6) — DIN (1985)
- EN 10250-3 / EN 10222-3 — Open die and pressure purpose forgings, nickel steels — CEN (2017)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- AD 2000-Merkblatt W 1 / EN 13445-2 material selection for low temperature — Verband der TÜV / CEN (2021)
- Low-temperature pressure vessel plate datasheets (1.6228 / 15NiMn6) — 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.