Steel 40CrMoV13-9 +QT+N (+QT + gas/plasma nitrided)
Heat-treated state
EN 40CrMoV13-9
Final service condition for wear surfaces: Q&T core plus 0.2–0.6 mm nitrided case for gears, screws and spindles.
Values for the +QT+N condition
Other 40CrMoV13-9 tempers and conditions
40CrMoV13-9 is listed in 6 conditions; see the grade overview at 40CrMoV13-9.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Delivery condition for bar/forging stock that will be rough machined and then quenched and tempered by the user. | 480 | 780 | 18 | 230 HB | — |
Normalized | Grain-refining intermediate condition after forging; this air-hardening steel comes out fairly hard, so annealing usually follows before machining. | 700 | 1,050 | 12 | 33 HRC | 5.7 % IACS |
+QT | Same heat treatment on large forgings/bars where reduced cooling rate lowers core strength slightly. | 820 | 1,050 | 13 | 32 HRC | 5.7 % IACS |
+QTDefault Quenched and tempered | Standard stocked condition: oil/air quenched from ~900–940 °C and tempered ~580–650 °C, ready for finish machining and subsequent nitriding. | 870 | 1,100 | 12 | 33 HRC | — |
+QT+NThis page +QT + gas/plasma nitrided | Final service condition for wear surfaces: Q&T core plus 0.2–0.6 mm nitrided case for gears, screws and spindles. | 870 | 1,100 | 11 | 33 HRC | — |
Quenched and tempered, peeled/turned and ground bar | Q&T bar supplied peeled or centreless ground for tight tolerance and decarburization-free surface before finish machining and nitriding. | 870 | 1,100 | 12 | 33 HRC | 5.7 % IACS |
What is 40CrMoV13-9 +QT+N?
40CrMoV13-9 +QT+N is 40CrMoV13-9 heat treated to +QT+N — final service condition for wear surfaces: Q&T core plus 0.2–0.6 mm nitrided case for gears, screws and spindles. 40CrMoV13-9 +QT+N has a yield strength of 870 MPa (126 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 89% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). 40CrMoV13-9 +QT+N 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 is the default condition FabDigit quotes; +QT+N is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Good corrosion resistance — 22/100, better than 90% of steel grades
- High strength — 870 MPa (126 ksi), better than 89% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to machine — 8/100, worse than 100% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
40CrMoV13-9 +QT+N properties
Typical room-temperature values for 40CrMoV13-9 +QT+N; 11 are specific to this condition. Other listed values are 40CrMoV13-9 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
40CrMoV13-9 +QT+N 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
40CrMoV13-9 +QT+N has a yield strength of 870 MPa (126 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 89% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
40CrMoV13-9 +QT+N is rated for continuous service to 500°C (932 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical2
40CrMoV13-9 +QT+N has an electrical resistivity of 3×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (22/100), better than 90% of steel grades.
Sustainability4
Producing a kilogram of 40CrMoV13-9 +QT+N takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability6
40CrMoV13-9 +QT+N's machinability is not recommended (8/100, worse than 100% of steel grades); weldability poor (20/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 40CrMoV13-9 +QT+N
Is 40CrMoV13-9 easy to machine?
Rough machine in the annealed condition and finish machine after Q&T at 300–360 HB with rigid setups, coated carbide and moderate speeds; leave 0.05–0.1 mm grinding stock because nitriding grows and slightly distorts the part.
Can 40CrMoV13-9 be welded?
Essentially not weldable in service condition — air-hardening with high carbon equivalent; if repair is unavoidable use matching or low-hydrogen filler with 300–400 °C preheat and immediate post-weld temper below the tempering temperature.
Can 40CrMoV13-9 be formed, bent or molded?
Hot forge 1100→850 °C with slow (furnace) cooling, then normalize and soft anneal; cold forming is impractical at this strength level.
What surface finishes work on 40CrMoV13-9?
Gas or plasma nitride at 500–530 °C after a stress-relief at ~30 °C below the tempering temperature; nitrided surfaces can be lightly lapped or superfinished, and un-nitrided areas need oiling, phosphating or plating for rust protection.
40CrMoV13-9 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 | 0.36 – 0.44 | 0.4 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.03 | — |
| Smax; lower S for high-integrity forgings | ≤ 0.04 | — |
| Cr | 3 – 3.5 | 3.25 |
| Mo | 0.8 – 1.1 | 0.95 |
| V | 0.15 – 0.25 | 0.2 |
| Fe | balance | — |
40CrMoV13-9 +QT+N — frequently asked
What is 40CrMoV13-9 +QT+N used for?
40CrMoV13-9 +QT+N is typically used for high-strength nitrided gears, aerospace shafts, heavy-duty crankshafts and precision spindles. In short: strongest core nitriding steel; vanadium-refined grain; grind after nitriding only.
What is the yield strength of 40CrMoV13-9 +QT+N?
40CrMoV13-9 +QT+N has a typical yield strength of 870 MPa (126 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 89% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 40CrMoV13-9 +QT+N easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of steel grades). Rough machine in the annealed condition and finish machine after Q&T at 300–360 HB with rigid setups, coated carbide and moderate speeds; leave 0.05–0.1 mm grinding stock because nitriding grows and slightly distorts the part.
Can 40CrMoV13-9 +QT+N be welded?
Not readily — weldability is rated poor (20/100). Essentially not weldable in service condition — air-hardening with high carbon equivalent; if repair is unavoidable use matching or low-hydrogen filler with 300–400 °C preheat and immediate post-weld temper below the tempering temperature.
What surface finishes work on 40CrMoV13-9 +QT+N?
Gas or plasma nitride at 500–530 °C after a stress-relief at ~30 °C below the tempering temperature; nitrided surfaces can be lightly lapped or superfinished, and un-nitrided areas need oiling, phosphating or plating for rust protection.
Can 40CrMoV13-9 +QT+N be formed, bent or molded?
Hot forge 1100→850 °C with slow (furnace) cooling, then normalize and soft anneal; cold forming is impractical at this strength level.
What is the maximum service temperature of 40CrMoV13-9 +QT+N?
40CrMoV13-9 +QT+N 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.
Sources
- EN 10085 — Nitriding steels: technical delivery conditions — CEN (2001)
- EN 10250-3 — Open die steel forgings, alloy special steels — CEN (1999)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4A/4D — Steel Heat Treating and Nitriding — ASM International (2013)
- Nitriding steel 1.8523 / 40CrMoV13-9 data sheet — European special-steel producers (e.g. Böhler/voestalpine, Deutsche Edelstahlwerke) (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.