Steel 34Cr4 +Q (Hardened)
Heat-treated state
EN 34Cr4
Intermediate as-quenched condition (austenitize ~850 °C, oil quench) — must be tempered promptly; not a service condition.
Values for the +Q condition
Other 34Cr4 tempers and conditions
34Cr4 is listed in 9 conditions; see the grade overview at 34Cr4.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold heading, cold extrusion or deep drilling — spheroidal carbides give the lowest work-hardening and best cold formability. | 330 | 565 | 25 | 172 HB | — |
Annealed | Softest delivery condition for heavy machining before hardening; hardness capped at 207 HB by EN 10083-3. | 360 | 600 | 22 | 185 HB | — |
Specified hardenability (Jominy band), delivered soft-annealed | Order this when the customer needs a guaranteed Jominy hardenability band (34Cr4+H) for parts that will be hardened after machining. | 360 | 600 | 22 | 51 HRC | 8 % IACS |
Normalized | Uniform fine-grained structure after hot working; used as a machining/pre-heat-treatment condition or for lightly loaded parts. | 430 | 720 | 18 | 18 HRC | — |
+QT | Heavy bars where limited hardenability (no Mo) drops core strength — use 42CrMo4 if higher core properties are needed. | 500 | 720 | 17 | 19 HRC | — |
Cold drawn | Bright drawn bar with close tolerance and smooth surface for automatic-lathe parts that will be hardened afterwards. | 620 | 760 | 9 | 20 HRC | 7.8 % IACS |
+QTDefault Quenched and tempered | Standard stocked engineering condition: 800–950 MPa tensile with 40 J Charpy — default for shafts, bolts and machine parts. | 640 | 880 | 16 | 27 HRC | — |
+QT | Highest strength grade class of 34Cr4 — small bars and fasteners fully hardened through the section. | 760 | 1,000 | 13 | 31 HRC | — |
+QThis page Hardened | Intermediate as-quenched condition (austenitize ~850 °C, oil quench) — must be tempered promptly; not a service condition. | 1,350 | 1,750 | 3 | 51 HRC | — |
What is 34Cr4 +Q?
34Cr4 +Q is 34Cr4 heat treated to +Q — intermediate as-quenched condition (austenitize ~850 °C, oil quench) — must be tempered promptly; not a service condition. 34Cr4 +Q has a yield strength of 1,350 MPa (196 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 95% of steel grades. Elongation at break is 3% and the elastic modulus is 210 GPa (30.5 Msi). 34Cr4 +Q has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). +QT is the default condition FabDigit quotes; +Q is available on request or by drawing note.
Advantages
- High strength — 1,350 MPa (196 ksi), better than 95% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited ductility — 3%, worse than 99% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
34Cr4 +Q properties
Typical room-temperature values for 34Cr4 +Q; 12 are specific to this condition. Other listed values are 34Cr4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
34Cr4 +Q has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
34Cr4 +Q has a yield strength of 1,350 MPa (196 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 95% of steel grades. Elongation at break is 3% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34Cr4 +Q is rated for continuous service to 150°C (302 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
34Cr4 +Q conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 34Cr4 +Q takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
34Cr4 +Q's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (15/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 34Cr4 +Q
Is 34Cr4 easy to machine?
Machine in the +A/+AC condition (65 % of 1212) with carbide or HSS; in +QT at ~280 HB use coated carbide, rigid setups and lower feeds — sulphurized 34CrS4 cuts noticeably better.
Can 34Cr4 be welded?
Weldable only with care (CE ≈ 0.6–0.7): preheat 200–300 °C, low-hydrogen consumables and stress-relief/re-temper at 550–650 °C to avoid HAZ cracking.
Can 34Cr4 be formed, bent or molded?
Cold head or upset only in +AC spheroidized condition; hot forge 1100–850 °C, then normalize before hardening (austenitize 830–870 °C, oil quench, temper 540–680 °C).
What surface finishes work on 34Cr4?
No corrosion resistance — protect with phosphating and oil, black oxide, zinc or Zn-Ni plating (bake to avoid hydrogen embrittlement above ~1000 MPa); surfaces can be induction hardened or nitrided.
34Cr4 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 – 0.37 | 0.34 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| Cr | 0.9 – 1.2 | 1.05 |
| P | ≤ 0.03 | — |
| S34CrS4 variant: S 0.020–0.040 for improved machinability | ≤ 0.04 | — |
| Moresidual only, not alloyed | ≤ 0.1 | — |
| Fe | balance | — |
34Cr4 +Q — frequently asked
What is 34Cr4 +Q used for?
34Cr4 +Q is typically used for bolts, shafts and connecting rods. In short: entry-level Cr through-hardening steel; medium-strength Q&T grade; limited weldability.
What is the yield strength of 34Cr4 +Q?
34Cr4 +Q has a typical yield strength of 1,350 MPa (196 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 95% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 34Cr4 +Q easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the +A/+AC condition (65 % of 1212) with carbide or HSS; in +QT at ~280 HB use coated carbide, rigid setups and lower feeds — sulphurized 34CrS4 cuts noticeably better.
Can 34Cr4 +Q be welded?
Not readily — weldability is rated poor (15/100). Weldable only with care (CE ≈ 0.6–0.7): preheat 200–300 °C, low-hydrogen consumables and stress-relief/re-temper at 550–650 °C to avoid HAZ cracking.
What surface finishes work on 34Cr4 +Q?
No corrosion resistance — protect with phosphating and oil, black oxide, zinc or Zn-Ni plating (bake to avoid hydrogen embrittlement above ~1000 MPa); surfaces can be induction hardened or nitrided.
Can 34Cr4 +Q be formed, bent or molded?
Cold head or upset only in +AC spheroidized condition; hot forge 1100–850 °C, then normalize before hardening (austenitize 830–870 °C, oil quench, temper 540–680 °C).
What is the maximum service temperature of 34Cr4 +Q?
34Cr4 +Q is rated for continuous use to about 150°C (302 °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)
- ISO 683-2 Heat-treatable steels, alloy steels and free-cutting steels — ISO (2016)
- SAE J404 Chemical Compositions of SAE Alloy Steels (5132) — SAE International (2009)
- GB/T 3077 (34Cr / 35Cr) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- Engineering steel 1.7033 / 34Cr4 bar datasheet — European long-products mill (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.