Steel 34CrMo4 +CH
Heat-treated state
EN 34CrMo4
+CH = 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.
Values for the +CH condition
Other 34CrMo4 tempers and conditions
34CrMo4 is listed in 9 conditions; see the grade overview at 34CrMo4.
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 | — |
+CHThis page 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 +CH?
34CrMo4 +CH is 34CrMo4 heat treated to +CH — pick for surface- or induction-hardened parts and tools needing a strong hard core (≈40–46 HRC) rather than a tough Q&T core. 34CrMo4 +CH has a yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,400 MPa (203 ksi) — stronger than 94% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi). 34CrMo4 +CH 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). +QT is the default condition FabDigit quotes; +CH is available on request or by drawing note.
Advantages
- High strength — 1,150 MPa (167 ksi), better than 94% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited formability — 8/100, worse than 97% of steel grades
- Limited ductility — 9%, worse than 93% of steel grades
- Difficult to machine — 32/100, worse than 87% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
34CrMo4 +CH properties
Typical room-temperature values for 34CrMo4 +CH; 16 are specific to this condition. Other listed values are 34CrMo4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
34CrMo4 +CH 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 +CH has a yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,400 MPa (203 ksi) — stronger than 94% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34CrMo4 +CH is rated for continuous service to 250°C (482 °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 +CH 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 +CH 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 +CH's machinability is poor (32/100, worse than 87% of steel grades); weldability poor (22/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 34CrMo4 +CH
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.
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.
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 | — |
34CrMo4 +CH — frequently asked
What is 34CrMo4 +CH used for?
34CrMo4 +CH 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 +CH?
34CrMo4 +CH has a typical yield strength of 1,150 MPa (167 ksi) and a tensile strength of 1,400 MPa (203 ksi) — stronger than 94% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 34CrMo4 +CH easy to machine?
Not especially — machinability is rated poor (32/100, worse than 87% 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 +CH be welded?
Not readily — weldability is rated poor (22/100). 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 +CH?
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 +CH 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 +CH?
34CrMo4 +CH is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.