Steel 30CrMoV9 +QT+NIT (+QT + gas/plasma nitrided)
Finish state
EN 30CrMoV9 · also Nitralloy 135
Pick for the final service condition: hard 0.2–0.6 mm nitrided case on a Q&T core for wear and bending fatigue.
Values for the +QT+NIT condition
Other 30CrMoV9 tempers and conditions
30CrMoV9 is listed in 8 conditions; see the grade overview at 30CrMoV9.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for bar/forging stock that must be rough machined or cold worked before hardening. | 500 | 780 | 18 | 20 HRC | — |
Normalized | Pick for forgings needing a uniform fine-grained structure prior to final quench and temper. | 600 | 900 | 14 | 26 HRC | 7.8 % IACS |
+QT | Pick for heavy forgings and large-diameter bar where hardenability limits core strength. | 650 | 880 | 13 | 27 HRC | — |
Cold drawn, annealed | Pick for small-diameter bright bar with close tolerance where only light machining precedes hardening. | 650 | 850 | 12 | 24 HRC | 8 % IACS |
+QT900Default +QT | Most commonly stocked condition: general-purpose Q&T bar/forging ready for finish machining and nitriding. | 750 | 1,000 | 11 | 31 HRC | — |
+QT+NITThis page +QT + gas/plasma nitrided | Pick for the final service condition: hard 0.2–0.6 mm nitrided case on a Q&T core for wear and bending fatigue. | 750 | 1,000 | 10 | 65 HRC | — |
+QT | Pick for medium shafts and gears; standard pre-nitriding condition for mid-size bar. | 850 | 1,100 | 11 | 35 HRC | — |
+QT | Pick for small-diameter shafts, pins and gear blanks where maximum core strength is needed. | 950 | 1,200 | 10 | 39 HRC | — |
What is 30CrMoV9 +QT+NIT?
30CrMoV9 +QT+NIT is 30CrMoV9 supplied in the +QT+NIT condition — pick for the final service condition: hard 0.2–0.6 mm nitrided case on a Q&T core for wear and bending fatigue. 30CrMoV9 +QT+NIT has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi). 30CrMoV9 +QT+NIT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,430°C (2,606 °F). +QT900 is the default condition FabDigit quotes; +QT+NIT is available on request or by drawing note.
Advantages
- Good corrosion resistance — 25/100, better than 92% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
- High strength — 750 MPa (109 ksi), better than 84% 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 — 10%, worse than 91% of steel grades
- Difficult to weld — 22/100, worse than 81% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
30CrMoV9 +QT+NIT properties
Typical room-temperature values for 30CrMoV9 +QT+NIT; 10 are specific to this condition. Other listed values are 30CrMoV9 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
30CrMoV9 +QT+NIT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,430°C (2,606 °F).
Mechanical16
30CrMoV9 +QT+NIT has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
30CrMoV9 +QT+NIT is rated for continuous service to 480°C (896 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
30CrMoV9 +QT+NIT conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of 30CrMoV9 +QT+NIT takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
30CrMoV9 +QT+NIT's machinability is not recommended (8/100, worse than 100% of steel grades); weldability poor (22/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 30CrMoV9 +QT+NIT
Is 30CrMoV9 easy to machine?
Finish machine in the Q&T condition (280–330 HB) with coated carbide, rigid setups and generous coolant; leave 0.02–0.05 mm stock only for post-nitride lapping since the case cannot be turned.
Can 30CrMoV9 be welded?
Essentially non-weldable for structural joints — high C plus 2.5% Cr gives a hard, crack-prone HAZ; if unavoidable, preheat 300–350 °C, use low-hydrogen Cr-Mo consumables and temper immediately after welding, and never weld nitrided surfaces.
Can 30CrMoV9 be formed, bent or molded?
Hot forge 1100–850 °C followed by slow cool and soft anneal (~650–700 °C); cold forming is limited to light straightening in the annealed condition.
What surface finishes work on 30CrMoV9?
Gas or plasma nitride 500–530 °C for 0.2–0.6 mm case at ≥800 HV; grind/superfinish before nitriding, then only lap or polish. Phosphating, black oxide or hard chrome can be applied where corrosion protection is needed.
30CrMoV9 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 | 0.26 – 0.34 | 0.3 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.03 | — |
| Smax (lower for high-quality/vacuum-degassed bar) | ≤ 0.04 | — |
| Cr | 2.3 – 2.7 | 2.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| V | 0.1 – 0.2 | 0.15 |
| Fe | balance | — |
30CrMoV9 +QT+NIT — frequently asked
What is 30CrMoV9 +QT+NIT used for?
30CrMoV9 +QT+NIT is typically used for large gears, worm shafts and nitrided components. In short: cr-Mo-V nitriding gear steel; nitrided case above 800 HV; not weldable structurally.
What is the yield strength of 30CrMoV9 +QT+NIT?
30CrMoV9 +QT+NIT has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 30CrMoV9 +QT+NIT easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of steel grades). Finish machine in the Q&T condition (280–330 HB) with coated carbide, rigid setups and generous coolant; leave 0.02–0.05 mm stock only for post-nitride lapping since the case cannot be turned.
Can 30CrMoV9 +QT+NIT be welded?
Not readily — weldability is rated poor (22/100). Essentially non-weldable for structural joints — high C plus 2.5% Cr gives a hard, crack-prone HAZ; if unavoidable, preheat 300–350 °C, use low-hydrogen Cr-Mo consumables and temper immediately after welding, and never weld nitrided surfaces.
What surface finishes work on 30CrMoV9 +QT+NIT?
Gas or plasma nitride 500–530 °C for 0.2–0.6 mm case at ≥800 HV; grind/superfinish before nitriding, then only lap or polish. Phosphating, black oxide or hard chrome can be applied where corrosion protection is needed.
Can 30CrMoV9 +QT+NIT be formed, bent or molded?
Hot forge 1100–850 °C followed by slow cool and soft anneal (~650–700 °C); cold forming is limited to light straightening in the annealed condition.
What is the maximum service temperature of 30CrMoV9 +QT+NIT?
30CrMoV9 +QT+NIT is rated for continuous use to about 480°C (896 °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)
- DIN 17211 (superseded) / Werkstoff 1.7707 data — DIN (1987)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol. 4A: Steel Heat Treating Fundamentals (nitriding) — ASM International (2013)
- Nitriding steel 1.7707 / 30CrMoV9 bar datasheet — Böhler / Ovako / Lucchini (comparable producer sheets) (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.