Steel 30CrNiMo8 · hardness band
Steel 30CrNiMo8 Q&T 36-40 HRC
Properties of the Q&T 36-40 HRC condition, compared with the other 30CrNiMo8 tempers.
Specify for heavily loaded transmission parts and high-strength bolts at 1080 MPa yield; cutting is already noticeably difficult, with machinability down to 34.
What is 30CrNiMo8 Q&T 36-40 HRC?
30CrNiMo8 Q&T 36-40 HRC is 30CrNiMo8 heat treated to Q&T 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. 30CrNiMo8 Q&T 36-40 HRC has a yield strength of 1,080 MPa (157 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 93% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). 30CrNiMo8 Q&T 36-40 HRC 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). Q&T is the default condition FabDigit quotes; Q&T 36-40 HRC is available on request or by drawing note.
Advantages
- High strength — 1,080 MPa (157 ksi), better than 93% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to machine — 34/100, worse than 86% of steel grades
- Limited formability — 18/100, worse than 84% of steel grades
- Difficult to weld — 22/100, worse than 81% 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 36-40 HRC properties
Typical room-temperature values for 30CrNiMo8 Q&T 36-40 HRC — 12 properties are specific to this condition; the rest are grade-level values shared by every 30CrNiMo8 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
30CrNiMo8 Q&T 36-40 HRC 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 36-40 HRC has a yield strength of 1,080 MPa (157 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 93% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
30CrNiMo8 Q&T 36-40 HRC 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 36-40 HRC conducts electricity at 7.5 % IACS, worse than 68% 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 36-40 HRC 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 36-40 HRC's machinability is poor (34/100, worse than 86% of steel grades); weldability poor (22/100); formability poor (18/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 30CrNiMo8 tempers and conditions
30CrNiMo8 is also supplied in 10 other conditions. The full side-by-side table is on the 30CrNiMo8 overview.
- Q&TDefaultMost 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 MPa yield · 38 HRC
- Q&T 40-44 HRCUse 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 MPa yield · 42 HRC
- +QT 1250Specify 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 MPa yield · 42 HRC
- Q&T 36-40 HRCSpecify 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 MPa yield · 38 HRC
- NitridedAdd 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 MPa yield · 58 HRC
- Q&T 32-36 HRCGeneral-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 MPa yield · 34 HRC
- +QT 1000Pick 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 MPa yield · 35 HRC
- Q&T 28-32 HRCChoose 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 MPa yield · 30 HRC
- +QT 900Use 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 MPa yield · 31 HRC
- +NUse normalising as an intermediate step after forging to refine and homogenise the structure; it is rarely specified as the final delivery condition.620 MPa yield · 28 HRC
- +AOrder 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 MPa yield · 225 HB
Working with 30CrNiMo8 Q&T 36-40 HRC
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 36-40 HRC — frequently asked
What is 30CrNiMo8 Q&T 36-40 HRC used for?
30CrNiMo8 Q&T 36-40 HRC 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 36-40 HRC?
30CrNiMo8 Q&T 36-40 HRC has a typical yield strength of 1,080 MPa (157 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 93% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 30CrNiMo8 Q&T 36-40 HRC easy to machine?
Not especially — machinability is rated poor (34/100, worse than 86% 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 36-40 HRC 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 36-40 HRC?
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 36-40 HRC 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 36-40 HRC?
30CrNiMo8 Q&T 36-40 HRC 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 36-40 HRC?
Yes — 30CrNiMo8 Q&T 36-40 HRC is available for CNC machining and sheet metal with instant online pricing. 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.