Steel 34CrNiMo6
EN 34CrNiMo6 · JIS SNCM439
34CrNiMo6 (1.6582) is a high-hardenability Cr-Ni-Mo through-hardening alloy steel from the EN 10083 family, equivalent to AISI 4340 and SNCM439, used for high-strength shafts, gears and structural parts.
Values for the HR condition
34CrNiMo6 tempers and conditions
34CrNiMo6 is supplied in 16 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
- Spheroidized
- Annealed
- HR
- Normalized
- CD
- QT900
- CR
- Q&T 28-32 HRC
- Q&T
- QT1000
- Nitrided
- Q&T 32-36 HRC
- QT1100
- QT1200
- Q&T 36-40 HRC
- Hardened
Compare all 16 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidized Annealed (+AC) | Sub-critical/cyclic anneal producing spheroidal carbides in ferrite — softest condition, best for cold forming, deep drilling and pre-machining. | 390 | 640 | 22 | 190 HB | 42 W/m·K |
soft annealed (max 248 HB) | Softest supply condition — pick for deep machining, cold work or before final quench and temper. | 490 | 760 | 20 | 18 HRC | — |
HRDefault Hot rolled | Mill as-rolled bar for re-forging or for parts that will be heat treated after machining. | 560 | 900 | 15 | 26 HRC | — |
normalized | Uniform fine-grain structure for forgings before final heat treatment or for moderately loaded parts. | 620 | 950 | 16 | 29 HRC | — |
Cold drawn | Bright, close-tolerance bar for shafting and turned parts machined without further heat treatment. | 720 | 900 | 10 | 27 HRC | — |
Q&T to 900–1100 MPa (sections 100–160 mm) | Higher-tempered condition for large sections or where maximum toughness/machinability is wanted. | 760 | 980 | 15 | 31 HRC | — |
Cold rolled | Cold-rolled flat product with tight thickness tolerance and bright surface; limited availability in this grade. | 780 | 950 | 8 | 30 HRC | 7.5 % IACS |
Hardness-specified quench and temper | Common purchase spec for shafting and API/oilfield parts needing good toughness and machinability. | 830 | 1,000 | 15 | 30 HRC | 7.5 % IACS |
Quenched and tempered | Standard commercial supply condition: oil quench from ~850 °C and temper ~570–650 °C for balanced strength and toughness. | 870 | 1,080 | 14 | 34 HRC | — |
Q&T to 1000–1200 MPa (sections 40–100 mm) | Mid-range EN 10083-3 strength class for medium shafts, gears and couplings. | 870 | 1,080 | 13 | 34 HRC | 7.5 % IACS |
Q&T core plus gas/plasma nitrided case | Choose when a 0.2–0.5 mm wear- and fatigue-resistant case is needed without distortion from re-hardening. | 870 | 1,080 | 13 | 34 HRC | — |
Hardness-specified quench and temper | Typical gear-blank and heavy-shaft hardness band; good balance of wear and impact resistance. | 950 | 1,120 | 13 | 34 HRC | 7.5 % IACS |
Q&T to 1100–1300 MPa (sections 16–40 mm) | High-strength class for smaller diameters — bolts, pins, connecting rods. | 970 | 1,180 | 12 | 37 HRC | — |
Q&T to 1200–1400 MPa (sections ≤16 mm) | Maximum standard strength class; use only in thin sections and where notch sensitivity is controlled. | 1,060 | 1,280 | 10 | 41 HRC | — |
Hardness-specified quench and temper | Upper hardness band for wear-loaded pins, spindles and tooling holders; machining becomes difficult. | 1,080 | 1,250 | 11 | 38 HRC | 7.5 % IACS |
Hardened (+H) | Austenitized ~850 °C and oil/polymer quenched to full martensite; maximum hardness but brittle — normally tempered before service. | 1,500 | 1,950 | 5 | 54 HRC | 34 W/m·K |
What is 34CrNiMo6?
34CrNiMo6 (1.6582) is a high-hardenability Cr-Ni-Mo through-hardening alloy steel from the EN 10083 family, equivalent to AISI 4340 and SNCM439, used for high-strength shafts, gears and structural parts. In the default Q&T condition it provides 560 MPa yield, 900 MPa tensile, 15 % elongation and 265 HB (26 HRC), and it is stocked hot rolled, cold drawn, annealed, normalized, spheroidized, nitrided and in QT900 to QT1200 strength classes up to Q&T 36–40 HRC. It has no corrosion resistance, welding needs preheat and immediate post-weld temper, and machinability (score 45) falls sharply above 36 HRC. 42CrMo4 is the usual lower-cost alternative in moderate sections. 34CrNiMo6 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). 34CrNiMo6 has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 73% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
What is 34CrNiMo6 used for?
- Drive shafts
- Aerospace landing gear components
- Gears and pinions
- Crankshafts
- High-strength bolts and studs
- Torsion bars
- Connecting rods
- Heavy die holders
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
34CrNiMo6 properties
Typical room-temperature values for 34CrNiMo6-HR; bars are the position among steel grades.
Physical3
34CrNiMo6 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
34CrNiMo6 has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 73% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34CrNiMo6 is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
34CrNiMo6 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 34CrNiMo6 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
34CrNiMo6's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (30/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 34CrNiMo6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 34CrNiMo6
Is 34CrNiMo6 easy to machine?
Machine in annealed (~215 HB) or Q&T ≤32 HRC condition with rigid setups, coated carbide, 80–140 m/min; above 36 HRC switch to CBN/ceramic or grinding.
Can 34CrNiMo6 be welded?
Weldable only with care: preheat 250–350 °C, low-hydrogen consumables, interpass control, and immediate post-weld temper 550–600 °C to avoid HAZ cracking.
Can 34CrNiMo6 be formed, bent or molded?
Hot forge 1100–850 °C then slow cool and normalize/anneal; cold forming limited to light straightening in the annealed condition.
Manufacturability
The process limits FabDigit applies to 34CrNiMo6. Every 34CrNiMo6 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better45 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair30 / 100 |
|---|---|
| Weldability | Better30 / 100 |
34CrNiMo6 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 | 0.3 – 0.38 | 0.34 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.03 | 0.01 |
| S≤0.035 base grade; +S grade 0.020–0.040, low-S grade ≤0.005 | ≤ 0.04 | 0.02 |
| Cr | 1.3 – 1.7 | 1.5 |
| Mo | 0.15 – 0.3 | 0.22 |
| Ni | 1.3 – 1.7 | 1.5 |
| Fe | balance |
What surface finishes work on 34CrNiMo6?
No anodizing — protect with oil, phosphate, black oxide, zinc-nickel or hard chrome; bake at 190–210 °C after plating to avoid hydrogen embrittlement; nitrides and polishes very well.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 34CrNiMo6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 34CrNiMo6 cost?
34CrNiMo6 is a standard-cost steel ($$), cheaper than about 61% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
34CrNiMo6 — frequently asked
What is 34CrNiMo6 used for?
34CrNiMo6 is typically used for drive shafts, aerospace landing gear components, gears and pinions, crankshafts, high-strength bolts and studs and torsion bars. In short: premium Ni-Cr-Mo bar.
What is the yield strength of 34CrNiMo6?
34CrNiMo6 has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 73% of steel grades. Strength varies by condition: see the 16 listed tempers.
Is 34CrNiMo6 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in annealed (~215 HB) or Q&T ≤32 HRC condition with rigid setups, coated carbide, 80–140 m/min; above 36 HRC switch to CBN/ceramic or grinding.
Can 34CrNiMo6 be welded?
Not readily — weldability is rated poor (30/100). Weldable only with care: preheat 250–350 °C, low-hydrogen consumables, interpass control, and immediate post-weld temper 550–600 °C to avoid HAZ cracking.
What surface finishes work on 34CrNiMo6?
No anodizing — protect with oil, phosphate, black oxide, zinc-nickel or hard chrome; bake at 190–210 °C after plating to avoid hydrogen embrittlement; nitrides and polishes very well.
Can 34CrNiMo6 be formed, bent or molded?
Hot forge 1100–850 °C then slow cool and normalize/anneal; cold forming limited to light straightening in the annealed condition.
What is the maximum service temperature of 34CrNiMo6?
34CrNiMo6 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 34CrNiMo6-HR and 34CrNiMo6-QT1200?
HR is the default condition — mill as-rolled bar for re-forging or for parts that will be heat treated after machining. QT1200: maximum standard strength class; use only in thin sections and where notch sensitivity is controlled. Yield strength is 560 MPa in HR versus 1,060 MPa in QT1200.
How much does 34CrNiMo6 cost?
34CrNiMo6 is a standard-cost steel ($$), cheaper than about 61% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 34CrNiMo6?
Yes — 34CrNiMo6 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 — Part 3: 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 and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Böhler V155 / 34CrNiMo6 datasheet — voestalpine BÖHLER Edelstahl (2022)
- Ovako 34CrNiMo6 (1.6582) steel data — Ovako (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.