Steel 42CrMoS4 Induction Hardened
Heat-treated state
EN 42CrMoS4 · AISI/SAE 4142 · GB 42CrMoS
For journals, splines and gear teeth needing a hard wear surface on a tough Q&T core.
Values for the Induction Hardened condition
Other 42CrMoS4 tempers and conditions
42CrMoS4 is listed in 16 conditions; see the grade overview at 42CrMoS4.
- +AC
- Annealed
- +FP
- +N
- Hot Rolled
- +QT750
- +QT800
- +C
- Q&T
- Nitrided
- Induction Hardened
- +CH
- Q&T 28-32 HRC
- +QT1000
- Q&T 32-36 HRC
- +QT1100
Compare all 16 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Sub-critical/spheroidizing anneal that converts the pearlitic carbides to globular form, giving the softest, most machinable and most cold-formable state of 1.7227 (typically ≤ 241 HB). | 440 | 680 | 22 | 195 HB | 44 W/m·K |
soft annealed (max 241 HB) | Pick for heavy machining/deep-hole work or cold forming before final quench and temper. | 460 | 700 | 18 | 205 HB | — |
Treated to ferrite-pearlite structure and hardness range | Best condition for automatic-lathe / high-volume machining of blanks that will be hardened later. | 500 | 780 | 16 | 16 HRC | 8.5 % IACS |
Normalized | Use for a uniform as-delivered structure in large forgings/bars before machining and final heat treatment. | 530 | 860 | 15 | 24 HRC | — |
as-rolled / as-forged bar | Cheapest stock form for parts that will be fully heat treated after rough machining. | 550 | 900 | 13 | 26 HRC | 8.5 % IACS |
+QT | Largest standard Q&T class for big forged rolls, rams and heavy shafts. | 560 | 825 | 15 | 24 HRC | — |
+QT | Heavy-section Q&T class; accepts the lower core strength from limited hardenability. | 610 | 875 | 14 | 27 HRC | — |
Cold drawn | Choose for close-tolerance bright bar going straight to turning/threading without further heat treatment. | 660 | 820 | 9 | 23 HRC | 8.5 % IACS |
Q&TDefault Quenched and tempered | Default stocked condition: oil-quenched and high-tempered for 900–1100 MPa strength with good toughness in medium sections. | 720 | 1,000 | 13 | 31 HRC | — |
Q&T + gas/plasma nitrided | Pick when wear resistance and fatigue strength of a Q&T core must be boosted without distortion. | 720 | 1,000 | 11 | 58 HRC | 8 % IACS |
Induction HardenedThis page Q&T core + induction hardened surface | For journals, splines and gear teeth needing a hard wear surface on a tough Q&T core. | 750 | 1,000 | 10 | 55 HRC | 8 % IACS |
Treatable to specified core hardness range | Through-hardened (oil quench + temper) 1.7227 bar supplied to a guaranteed core hardness band, giving a uniform ~300 HB tempered-martensite core in medium sections. | 800 | 1,000 | 13 | 31 HRC | 42 W/m·K |
Q&T to 28–32 HRC | Common purchased hardness band for machinable shafting, gear blanks and hydraulic parts. | 800 | 960 | 15 | 30 HRC | — |
+QT | Standard class for shafts and spindles 16–40 mm needing ≥750 MPa yield. | 830 | 1,100 | 12 | 34 HRC | — |
Q&T to 32–36 HRC | Higher-strength purchased band for highly loaded shafts, tooling holders and fasteners. | 930 | 1,080 | 13 | 34 HRC | — |
+QT | Highest-strength Q&T class, small bars and fasteners where full through-hardening is achieved. | 980 | 1,180 | 11 | 37 HRC | — |
What is 42CrMoS4 Induction Hardened?
42CrMoS4 Induction Hardened is 42CrMoS4 heat treated to Induction Hardened — for journals, splines and gear teeth needing a hard wear surface on a tough Q&T core. 42CrMoS4 Induction Hardened 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 10% and the elastic modulus is 210 GPa (30.5 Msi). 42CrMoS4 Induction Hardened has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). Q&T is the default condition FabDigit quotes; Induction Hardened is available on request or by drawing note.
Advantages
- 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
- Difficult to weld — 5/100, worse than 100% of steel grades
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
42CrMoS4 Induction Hardened properties
Typical room-temperature values for 42CrMoS4 Induction Hardened; 22 are specific to this condition. Other listed values are 42CrMoS4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
42CrMoS4 Induction Hardened has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical16
42CrMoS4 Induction Hardened 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 10% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
42CrMoS4 Induction Hardened is rated for continuous service to 200°C (392 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.1 µm/m·K (6.17 µin/in·°F).
Electrical3
42CrMoS4 Induction Hardened 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 42CrMoS4 Induction Hardened takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
42CrMoS4 Induction Hardened's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (5/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 42CrMoS4 Induction Hardened
Is 42CrMoS4 easy to machine?
Machines best at 200–260 HB; the 0.02–0.04 % S gives short chips and ~10–15 % better tool life than 42CrMo4 — use coated carbide, rigid setups and reduce speeds sharply above 320 HB.
Can 42CrMoS4 be welded?
Weldable only with care: preheat 250–350 °C, low-hydrogen consumables, interpass control and post-weld temper/stress relief below the last tempering temperature; the sulphur raises hot-cracking risk, so 42CrMo4 (non-resulphurised) is preferred for welded assemblies.
Can 42CrMoS4 be formed, bent or molded?
Hot forge 1100–850 °C then slow-cool or normalize; cold forming only in the annealed/+FP state with generous radii — Q&T material is essentially non-formable.
What surface finishes work on 42CrMoS4?
Takes hard chrome, zinc/zinc-nickel, phosphate, black oxide, nitriding and paint; bake at 190–220 °C after acid pickling/plating to avoid hydrogen embrittlement, and expect fine sulphide streaks on high-polish surfaces.
42CrMoS4 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 | 0.38 – 0.45 | 0.42 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | 0.02 |
| Sdeliberate S addition for machinability (the 'S' in 42CrMoS4) | 0.02 – 0.04 | 0.03 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Fe | balance | — |
42CrMoS4 Induction Hardened — frequently asked
What is 42CrMoS4 Induction Hardened used for?
42CrMoS4 Induction Hardened is typically used for shafts, bolts and studs. In short: free-cutting Cr-Mo bar.
What is the yield strength of 42CrMoS4 Induction Hardened?
42CrMoS4 Induction Hardened 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 16 listed tempers.
Is 42CrMoS4 Induction Hardened easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machines best at 200–260 HB; the 0.02–0.04 % S gives short chips and ~10–15 % better tool life than 42CrMo4 — use coated carbide, rigid setups and reduce speeds sharply above 320 HB.
Can 42CrMoS4 Induction Hardened be welded?
Not readily — weldability is rated not recommended (5/100). Weldable only with care: preheat 250–350 °C, low-hydrogen consumables, interpass control and post-weld temper/stress relief below the last tempering temperature; the sulphur raises hot-cracking risk, so 42CrMo4 (non-resulphurised) is preferred for welded assemblies.
What surface finishes work on 42CrMoS4 Induction Hardened?
Takes hard chrome, zinc/zinc-nickel, phosphate, black oxide, nitriding and paint; bake at 190–220 °C after acid pickling/plating to avoid hydrogen embrittlement, and expect fine sulphide streaks on high-polish surfaces.
Can 42CrMoS4 Induction Hardened be formed, bent or molded?
Hot forge 1100–850 °C then slow-cool or normalize; cold forming only in the annealed/+FP state with generous radii — Q&T material is essentially non-formable.
What is the maximum service temperature of 42CrMoS4 Induction Hardened?
42CrMoS4 Induction Hardened is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 42CrMoS4 Induction Hardened?
Yes — 42CrMoS4 Induction Hardened is available for CNC machining; 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 10277 / EN 10278 bright steel product standards — CEN (2018)
- GB/T 3077 (42CrMo) — SAC (2015)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol. 19 — Fatigue and Fracture — ASM International (1996)
- 1.7225 / 1.7227 (42CrMo4, 42CrMoS4) engineering steel datasheets — Ovako / Böhler / Deutsche Edelstahlwerke (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.