Steel 35NiCrMo16 QT-1850
Heat-treated state
EN 35NiCrMo16
QT-1850 = q&T 1800–2000 MPa
Only for compression-dominated or strength-critical parts; toughness and hydrogen-embrittlement resistance are at their lowest.
Values for the QT-1850 condition
Other 35NiCrMo16 tempers and conditions
35NiCrMo16 is listed in 7 conditions; see the grade overview at 35NiCrMo16.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for rough machining, deep hole drilling or cold straightening before final Q&T. | 620 | 900 | 16 | 26 HRC | — |
Normalized | Intermediate stock condition for forgings before final quench and temper; not a service condition. | 800 | 1,150 | 13 | 36 HRC | 5.9 % IACS |
+QT 1100–1300 MPa | Standard EN 10083-3 condition for large-diameter bars and forgings where toughness is prioritised over peak strength. | 950 | 1,200 | 13 | 38 HRC | — |
Q&T + gas/plasma nitrided | Choose when a wear-resistant, fatigue-strengthened surface is needed on an already tough Q&T core (gears, spindles, pins). | 1,100 | 1,300 | 10 | 60 HRC | — |
+QT-1250Default +QT 1250–1450 MPa | Default stocked condition: best balance of ~1350 MPa strength with 40+ J Charpy for shafts, gears and highly loaded fasteners. | 1,150 | 1,350 | 11 | 43 HRC | — |
Q&T 1600–1800 MPa | Use for landing-gear and highly stressed aerospace parts where 1700 MPa is required; demands strict hydrogen and notch control. | 1,500 | 1,700 | 9 | 50 HRC | — |
QT-1850This page Q&T 1800–2000 MPa | Only for compression-dominated or strength-critical parts; toughness and hydrogen-embrittlement resistance are at their lowest. | 1,650 | 1,900 | 7 | 54 HRC | — |
What is 35NiCrMo16 QT-1850?
35NiCrMo16 QT-1850 is 35NiCrMo16 heat treated to QT-1850 — only for compression-dominated or strength-critical parts; toughness and hydrogen-embrittlement resistance are at their lowest. 35NiCrMo16 QT-1850 has a yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 99% of steel grades. Elongation at break is 7% and the elastic modulus is 205 GPa (29.7 Msi). 35NiCrMo16 QT-1850 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). +QT-1250 is the default condition FabDigit quotes; QT-1850 is available on request or by drawing note.
Advantages
- High strength — 1,650 MPa (239 ksi), better than 99% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited ductility — 7%, worse than 96% of steel grades
- Limited formability — 12/100, worse than 92% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Low fracture toughness — 48 MPa·√m (43.7 ksi·√in), worse than 88% of steel grades
35NiCrMo16 QT-1850 properties
Typical room-temperature values for 35NiCrMo16 QT-1850; 12 are specific to this condition. Other listed values are 35NiCrMo16 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
35NiCrMo16 QT-1850 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
35NiCrMo16 QT-1850 has a yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 99% of steel grades. Elongation at break is 7% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
35NiCrMo16 QT-1850 is rated for continuous service to 250°C (482 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical2
35NiCrMo16 QT-1850 has an electrical resistivity of 3×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 35NiCrMo16 QT-1850 takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
35NiCrMo16 QT-1850's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (15/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 35NiCrMo16 QT-1850
Is 35NiCrMo16 easy to machine?
Rough-machine in the +A condition (≈265 HB); in the Q&T state above 40 HRC use rigid setups, coated carbide or CBN at low feeds, and finish-grind close-tolerance features.
Can 35NiCrMo16 be welded?
Poor weldability due to high carbon equivalent — if unavoidable, preheat 250–350 °C, use low-hydrogen filler, maintain interpass temperature and re-temper below the last tempering temperature immediately after welding.
Can 35NiCrMo16 be formed, bent or molded?
Hot forge 1100–850 °C with slow post-forge cooling to avoid quench cracks; cold forming limited to mild straightening in the annealed state.
What surface finishes work on 35NiCrMo16?
No anodizing; protect with Zn-Ni or cadmium plating, hard chrome, phosphate+oil or primer/paint, and bake at 190–200 °C after plating to relieve hydrogen; nitriding or shot peening boosts fatigue life.
35NiCrMo16 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 |
|---|---|---|
| CAFNOR NF A35-565 / EN 10083-3 | 0.32 – 0.39 | 0.35 |
| Si | ≤ 0.35 | 0.25 |
| Mn | 0.3 – 0.6 | 0.45 |
| Paerospace melts typically ≤0.015 | ≤ 0.03 | 0.01 |
| S≤0.010 for aerospace | ≤ 0.02 | 0.01 |
| Cr | 1.6 – 2 | 1.8 |
| Mo | 0.25 – 0.45 | 0.35 |
| Nigives very deep hardenability and low-temperature toughness | 3.6 – 4.1 | 3.85 |
| Fe | balance | — |
35NiCrMo16 QT-1850 — frequently asked
What is 35NiCrMo16 QT-1850 used for?
35NiCrMo16 QT-1850 is typically used for landing gear, high-strength bolts, large gears and shafts. In short: deep-hardening Ni-Cr-Mo steel; tempers to 1850 MPa; poor weldability, low machinability.
What is the yield strength of 35NiCrMo16 QT-1850?
35NiCrMo16 QT-1850 has a typical yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,900 MPa (276 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 35NiCrMo16 QT-1850 easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Rough-machine in the +A condition (≈265 HB); in the Q&T state above 40 HRC use rigid setups, coated carbide or CBN at low feeds, and finish-grind close-tolerance features.
Can 35NiCrMo16 QT-1850 be welded?
Not readily — weldability is rated poor (15/100). Poor weldability due to high carbon equivalent — if unavoidable, preheat 250–350 °C, use low-hydrogen filler, maintain interpass temperature and re-temper below the last tempering temperature immediately after welding.
What surface finishes work on 35NiCrMo16 QT-1850?
No anodizing; protect with Zn-Ni or cadmium plating, hard chrome, phosphate+oil or primer/paint, and bake at 190–200 °C after plating to relieve hydrogen; nitriding or shot peening boosts fatigue life.
Can 35NiCrMo16 QT-1850 be formed, bent or molded?
Hot forge 1100–850 °C with slow post-forge cooling to avoid quench cracks; cold forming limited to mild straightening in the annealed state.
What is the maximum service temperature of 35NiCrMo16 QT-1850?
35NiCrMo16 QT-1850 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 35NiCrMo16 +QT-1250 and 35NiCrMo16 QT-1850?
+QT-1250 is the default condition — default stocked condition: best balance of ~1350 MPa strength with 40+ J Charpy for shafts, gears and highly loaded fasteners. QT-1850: only for compression-dominated or strength-critical parts; toughness and hydrogen-embrittlement resistance are at their lowest. Yield strength is 1,150 MPa in +QT-1250 versus 1,650 MPa in QT-1850.
Sources
- EN 10083-3 Steels for quenching and tempering — Part 3: Alloy steels (36NiCrMo16 / 1.6773) — CEN (2006)
- NF A35-565 Aciers alliés de traitement thermique (35NiCrMo16) — AFNOR (1985)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- Stahlschlüssel (Key to Steel), entry 1.6773 — Verlag Stahlschlüssel Wegst (2019)
- High-strength Ni-Cr-Mo aerospace bar (36NiCrMo16) datasheet — Aubert & Duval / Lucchini / Böhler (2022)
- MMPDS-17 (comparative 4340/300M-class strength-toughness data) — Battelle/FAA (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.