Steel 30CrNiMo8 Q&T (Quenched and tempered)
Heat-treated state · default condition
EN 30CrNiMo8
Most common stock condition: oil quenched and high-temperature tempered in 40–100 mm sections for 1100–1300 MPa tensile with a balanced combination of strength and toughness.
Values for the Q&T condition
Other 30CrNiMo8 tempers and conditions
30CrNiMo8 is listed in 11 conditions; see the grade overview at 30CrNiMo8.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Order soft annealed (max 248 HB) as the easiest state for machining and cold forming; rough-machine first, then quench and temper the part to its final strength level. | 520 | 780 | 18 | 225 HB | — |
Normalized | Use normalising as an intermediate step after forging to refine and homogenise the structure; it is rarely specified as the final delivery condition. | 620 | 950 | 15 | 28 HRC | — |
+QT 160–250 mm | Use these guaranteed values for very large forged sections of 160–250 mm (Rm 900–1100 MPa, Re ≥700 MPa): lower core strength but the best toughness of the quenched and tempered range. | 780 | 1,000 | 14 | 31 HRC | — |
Q&T to 28–32 HRC | Choose this machining-friendly low hardness band of the quench-and-temper range for large die sets, flanges and parts that may need weld repair after rough machining. | 830 | 1,000 | 15 | 30 HRC | — |
+QT 100–160 mm | Pick for heavy forgings and large-diameter bar of 100–160 mm (Rm 1000–1200 MPa, Re ≥800 MPa), balancing through-section hardenability against toughness. | 880 | 1,100 | 13 | 35 HRC | — |
Q&T to 32–36 HRC | General-purpose high-strength band after quenching and tempering — the usual hardness for shafts, gear blanks and connecting rods, giving 950 MPa yield with 13% elongation. | 950 | 1,120 | 13 | 34 HRC | — |
Q&TDefaultThis page Quenched and tempered | Most common stock condition: oil quenched and high-temperature tempered in 40–100 mm sections for 1100–1300 MPa tensile with a balanced combination of strength and toughness. | 1,000 | 1,200 | 12 | 38 HRC | — |
Q&T + gas/plasma nitrided case | Add a 0.2–0.5 mm gas or plasma nitrided case over the quenched and tempered core for wear and fatigue life with very little distortion; the 58 HRC surface is effectively unmachinable. | 1,000 | 1,200 | 11 | 58 HRC | — |
Q&T to 36–40 HRC | Specify for heavily loaded transmission parts and high-strength bolts at 1080 MPa yield; cutting is already noticeably difficult, with machinability down to 34. | 1,080 | 1,250 | 11 | 38 HRC | — |
+QT ≤40 mm | Specify for bar up to 40 mm delivered to the highest EN 10083-3 strength class (Rm 1250–1450 MPa, Re ≥1050 MPa) for high-stress bolts and shafts; machinability falls to 32. | 1,120 | 1,330 | 10 | 42 HRC | — |
Q&T to 40–44 HRC | Use low-temperature tempering for small sections needing the highest strength and wear resistance; toughness drops to 9% elongation and temper-embrittlement ranges must be avoided. | 1,220 | 1,400 | 9 | 42 HRC | — |
What is 30CrNiMo8 Q&T?
30CrNiMo8 Q&T is 30CrNiMo8 heat treated to Q&T — most common stock condition: oil quenched and high-temperature tempered in 40–100 mm sections for 1100–1300 MPa tensile with a balanced combination of strength and toughness. 30CrNiMo8 Q&T has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 92% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi). 30CrNiMo8 Q&T 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).
Advantages
- High strength — 1,000 MPa (145 ksi), better than 92% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Limited formability — 18/100, worse than 84% of steel grades
- Difficult to weld — 22/100, worse than 81% of steel grades
- Difficult to machine — 38/100, 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
30CrNiMo8 Q&T properties
Typical room-temperature values for 30CrNiMo8 Q&T; 13 are specific to this condition. Other listed values are 30CrNiMo8 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
30CrNiMo8 Q&T 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
30CrNiMo8 Q&T has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 92% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
30CrNiMo8 Q&T is rated for continuous service to 350°C (662 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
30CrNiMo8 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 30CrNiMo8 Q&T 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
30CrNiMo8 Q&T's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (22/100); formability poor (18/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 30CrNiMo8 Q&T
Is 30CrNiMo8 easy to machine?
Rough machine in the annealed condition (≤248 HB) for lowest cost; at 32–40 HRC use coated carbide with reduced speed, heavier feed, rigid setups and steady coolant — machinability is about 35–50% of AISI 1212.
Can 30CrNiMo8 be welded?
Carbon equivalent is high (CE ≈ 0.9), so welding is generally not recommended; where unavoidable use low-hydrogen consumables, preheat 250–350 °C, hold interpass temperature and temper immediately at 550–650 °C.
Can 30CrNiMo8 be formed, bent or molded?
Hot forge 1100–850 °C then slow cool or normalize; cold forming is limited to the annealed condition with small deformation, and quenched-and-tempered material is effectively not cold bendable.
What surface finishes work on 30CrNiMo8?
Grinds and polishes to a mirror finish; protect with black oxide/phosphate, zinc-nickel or hard chrome plating (bake parts at ≥40 HRC for 4–24 h at 190–210 °C for hydrogen relief), and use gas or ion nitriding where wear resistance is required.
30CrNiMo8 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 | 0.3 – 0.6 | 0.45 |
| PEN 10083-3 base level | ≤ 0.03 | |
| Sfree-machining grade may be 0.020-0.040 | ≤ 0.04 | |
| Cr | 1.8 – 2.2 | 2 |
| Mo | 0.3 – 0.5 | 0.4 |
| Ni | 1.8 – 2.2 | 2 |
| Fe | balance |
30CrNiMo8 Q&T — frequently asked
What is 30CrNiMo8 Q&T used for?
30CrNiMo8 Q&T is typically used for large forged drive shafts, industrial axles, heavily loaded gears, crankshafts, rock-drill and mining components and high-strength bolts and studs. In short: premium Ni-Cr-Mo bar.
What is the yield strength of 30CrNiMo8 Q&T?
30CrNiMo8 Q&T has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 92% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 30CrNiMo8 Q&T easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Rough machine in the annealed condition (≤248 HB) for lowest cost; at 32–40 HRC use coated carbide with reduced speed, heavier feed, rigid setups and steady coolant — machinability is about 35–50% of AISI 1212.
Can 30CrNiMo8 Q&T be welded?
Not readily — weldability is rated poor (22/100). Carbon equivalent is high (CE ≈ 0.9), so welding is generally not recommended; where unavoidable use low-hydrogen consumables, preheat 250–350 °C, hold interpass temperature and temper immediately at 550–650 °C.
What surface finishes work on 30CrNiMo8 Q&T?
Grinds and polishes to a mirror finish; protect with black oxide/phosphate, zinc-nickel or hard chrome plating (bake parts at ≥40 HRC for 4–24 h at 190–210 °C for hydrogen relief), and use gas or ion nitriding where wear resistance is required.
Can 30CrNiMo8 Q&T be formed, bent or molded?
Hot forge 1100–850 °C then slow cool or normalize; cold forming is limited to the annealed condition with small deformation, and quenched-and-tempered material is effectively not cold bendable.
What is the maximum service temperature of 30CrNiMo8 Q&T?
30CrNiMo8 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.
Can FabDigit make parts in 30CrNiMo8 Q&T?
Yes — 30CrNiMo8 Q&T is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- EN 10250-3 Open die steel forgings — Alloy special steels — CEN (1999)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Böhler V320 / Ovako 30CrNiMo8 datasheet — voestalpine BÖHLER / Ovako (2022)
- BS 970 / 817M40 alloy steel bar — BSI (1991)
- SMM / Mysteel (2026)
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.