Steel 42CrMoS4
EN 42CrMoS4 · AISI/SAE 4142 · GB 42CrMoS
42CrMoS4 (1.7227) is the resulphurised, free-machining version of the EN 10083 42CrMo4 chromium-molybdenum through-hardening steel, close to AISI 4140/4142.
Values for the Q&T condition
42CrMoS4 tempers and conditions
42CrMoS4 is supplied in 16 conditions, soft to hard. Q&T is the default FabDigit quotes; the values on this page are for it.
- +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 |
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?
42CrMoS4 (1.7227) is the resulphurised, free-machining version of the EN 10083 42CrMo4 chromium-molybdenum through-hardening steel, close to AISI 4140/4142. In the default quenched and tempered condition it gives about 720 MPa yield, 1000 MPa tensile, 13% elongation and 300 HB, and is stocked as bar, forgings and blanks for shafts, fasteners and gear parts in service up to about 425 °C. The 0.02–0.04% sulphur that shortens chips also costs some toughness and raises hot-cracking risk, so non-resulphurised 42CrMo4 is the better choice for welded assemblies. 42CrMoS4 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). 42CrMoS4 has a yield strength of 720 MPa (104 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
What is 42CrMoS4 used for?
- Shafts
- Bolts
- Studs
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 720 MPa (104 ksi), better than 82% of steel grades
Limitations
- Limited ductility — 13%, worse than 78% of steel grades
42CrMoS4 properties
Typical room-temperature values for 42CrMoS4-Q&T; bars are the position among steel grades.
Physical3
42CrMoS4 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 has a yield strength of 720 MPa (104 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
42CrMoS4 is rated for continuous service to 425°C (797 °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 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 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's machinability is fair (50/100, worse than 53% of steel grades); weldability poor (30/100); 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. 42CrMoS4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 42CrMoS4
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.
Manufacturability
The process limits FabDigit applies to 42CrMoS4. Every 42CrMoS4 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Excellent50 / 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 |
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 |
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.
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 42CrMoS4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 42CrMoS4 cost?
42CrMoS4 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
42CrMoS4 — frequently asked
What is 42CrMoS4 used for?
42CrMoS4 is typically used for shafts, bolts and studs. In short: free-cutting Cr-Mo bar.
What is the yield strength of 42CrMoS4?
42CrMoS4 has a typical yield strength of 720 MPa (104 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of steel grades. Strength varies by condition: see the 16 listed tempers.
Is 42CrMoS4 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines best at 200–260 HB; the 0.02–0.04 % S gives short chips and ~10–15 % better tool life than 42CrMo4 — use coated carbide, rigid setups and reduce speeds sharply above 320 HB.
Can 42CrMoS4 be welded?
Not readily — weldability is rated poor (30/100). Weldable only with care: preheat 250–350 °C, low-hydrogen consumables, interpass control and post-weld temper/stress relief below the last tempering temperature; the sulphur raises hot-cracking risk, so 42CrMo4 (non-resulphurised) is preferred for welded assemblies.
What surface finishes work on 42CrMoS4?
Takes hard chrome, zinc/zinc-nickel, phosphate, black oxide, nitriding and paint; bake at 190–220 °C after acid pickling/plating to avoid hydrogen embrittlement, and expect fine sulphide streaks on high-polish surfaces.
Can 42CrMoS4 be formed, bent or molded?
Hot forge 1100–850 °C then slow-cool or normalize; cold forming only in the annealed/+FP state with generous radii — Q&T material is essentially non-formable.
What is the maximum service temperature of 42CrMoS4?
42CrMoS4 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 42CrMoS4 cost?
42CrMoS4 is a budget-cost steel ($), 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.
Can FabDigit make parts in 42CrMoS4?
Yes — 42CrMoS4 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; 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.