Steel 34CrMo4
EN 34CrMo4
34CrMo4 (1.7220) is a Cr-Mo quench-and-temper alloy steel equivalent to AISI 4135/4137, 35CrMo and SCM430.
Reference datasheet — 34CrMo4 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +QT condition
34CrMo4 tempers and conditions
34CrMo4 is supplied in 9 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Pick for cold heading, cold extrusion or deep drilling where the softest, most ductile structure is needed. | 350 | 560 | 25 | 178 HB | — |
Annealed | Pick for easiest machining, cold work or as the delivery state before customer heat treatment. | 400 | 620 | 20 | 195 HB | — |
Normalized | Pick for uniform fine grain and moderate strength in hot-rolled or forged parts that will not be quenched. | 480 | 750 | 18 | 220 HB | — |
+QT | Pick for large forged shafts and flanges where limited hardenability lowers the guaranteed strength class. | 620 | 880 | 15 | 26 HRC | — |
Cold drawn | Pick for close-tolerance bright bar and screw-machine work where moderate strength without heat treatment is enough. | 650 | 800 | 10 | 22 HRC | — |
+QTDefault Quenched and tempered | Standard stocked condition: best balance of strength, toughness and fatigue for shafts, gears and pressure parts. | 750 | 1,000 | 12 | 31 HRC | — |
+QT | Pick for small-diameter bar, bolts and pins where full through-hardening gives the highest EN 10083-3 strength class. | 850 | 1,100 | 11 | 35 HRC | — |
Core hardened / hardened and low-temperature tempered | Pick for surface- or induction-hardened parts and tools needing a strong hard core (≈40–46 HRC) rather than a tough Q&T core. | 1,150 | 1,400 | 9 | 44 HRC | — |
Hardened | Pick when maximum as-quenched martensite hardness or a guaranteed Jominy band is required; parts must be tempered before service. | 1,350 | 1,750 | 4 | 52 HRC | — |
What is 34CrMo4?
34CrMo4 (1.7220) is a Cr-Mo quench-and-temper alloy steel equivalent to AISI 4135/4137, 35CrMo and SCM430. Engineers choose it for shafts, gears and pressure-retaining fittings needing through-hardened strength in medium sections; it is stocked as bar, tube and forging stock in +A, +AC, +N, +H, +CH, +QT and +C conditions. The default +QT state gives 750 MPa yield, 1000 MPa tensile, 12 % elongation and 300 HB (31 HRC), with service to 500 °C and machinability rated 52. It has no corrosion resistance, only moderate weldability (40) and low formability (25); 42CrMo4/4140 is the step up when higher strength is required. 34CrMo4 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). 34CrMo4 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 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 34CrMo4 used for?
- shafts
- gears
- pressure vessel fittings
- couplings
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 750 MPa (109 ksi), better than 84% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
34CrMo4 properties
Typical room-temperature values for 34CrMo4-+QT; bars are the position among steel grades.
Physical3
34CrMo4 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
34CrMo4 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 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34CrMo4 is rated for continuous service to 500°C (932 °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
34CrMo4 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 34CrMo4 takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 35%.
Manufacturability7
34CrMo4's machinability is fair (52/100, better than 52% of steel grades); weldability fair (40/100); formability poor (25/100).
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. 34CrMo4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 34CrMo4
Is 34CrMo4 easy to machine?
Machine in +A/+AC (≈65–70 % of 1212) or at ≤32 HRC after Q&T; use rigid setups, coated carbide and coolant — above 40 HRC switch to CBN/ceramic.
Can 34CrMo4 be welded?
CE ≈ 0.75, so preheat 250–350 °C, use low-hydrogen consumables and temper/stress-relieve at 550–650 °C after welding to avoid HAZ cracking.
Can 34CrMo4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold heading and bending only in spheroidized (+AC) condition with generous bend radii.
34CrMo4 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 |
|---|---|---|
| CEN 10083-3 | 0.3 – 0.37 | 0.34 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P0.035 max in some national grades | ≤ 0.03 | 0.02 |
| S34CrMoS4 variant 0.020–0.040 S | ≤ 0.04 | 0.02 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Fe | balance |
What surface finishes work on 34CrMo4?
No natural corrosion protection — phosphate + oil, zinc or Zn-Ni plate (bake to avoid H embrittlement above 1000 MPa), nitride or QPQ for wear, or paint.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 34CrMo4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 34CrMo4 cost?
34CrMo4 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
34CrMo4 — frequently asked
What is 34CrMo4 used for?
34CrMo4 is typically used for shafts, gears, pressure vessel fittings and couplings. In short: lower-carbon 4140 alternative; weldable Cr-Mo Q&T steel; service to 500 °C.
What is the yield strength of 34CrMo4?
34CrMo4 has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 34CrMo4 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machine in +A/+AC (≈65–70 % of 1212) or at ≤32 HRC after Q&T; use rigid setups, coated carbide and coolant — above 40 HRC switch to CBN/ceramic.
Can 34CrMo4 be welded?
With care — weldability is rated fair (40/100). CE ≈ 0.75, so preheat 250–350 °C, use low-hydrogen consumables and temper/stress-relieve at 550–650 °C after welding to avoid HAZ cracking.
What surface finishes work on 34CrMo4?
No natural corrosion protection — phosphate + oil, zinc or Zn-Ni plate (bake to avoid H embrittlement above 1000 MPa), nitride or QPQ for wear, or paint.
Can 34CrMo4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold heading and bending only in spheroidized (+AC) condition with generous bend radii.
What is the maximum service temperature of 34CrMo4?
34CrMo4 is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 34CrMo4 cost?
34CrMo4 is a budget-cost steel ($), cheaper than about 90% 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.
Sources
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- GB/T 3077 (35CrMo) — SAC (2015)
- JIS G 4105 Chromium molybdenum steels (SCM430) — JSA (2015)
- ASTM A29/A29M & A322 (AISI 4135/4137) — ASTM International (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- 34CrMo4 / 1.7220 engineering steel datasheet — Ovako / voestalpine Böhler (2022)
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.