Steel 42CrMoS4 Hot Rolled
Finish state
EN 42CrMoS4 · AISI/SAE 4142 · GB 42CrMoS
Cheapest stock form for parts that will be fully heat treated after rough machining.
Values for the Hot Rolled 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 | — |
Hot RolledThis page 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 Hot Rolled?
42CrMoS4 Hot Rolled is 42CrMoS4 supplied in the Hot Rolled condition — cheapest stock form for parts that will be fully heat treated after rough machining. 42CrMoS4 Hot Rolled has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi). 42CrMoS4 Hot Rolled 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; Hot Rolled is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited ductility — 13%, worse than 78% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
42CrMoS4 Hot Rolled properties
Typical room-temperature values for 42CrMoS4 Hot Rolled; 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 Hot Rolled 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 Hot Rolled has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
42CrMoS4 Hot Rolled is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.1 µm/m·K (6.17 µin/in·°F).
Electrical3
42CrMoS4 Hot Rolled conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 42CrMoS4 Hot Rolled 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 Hot Rolled's machinability is fair (50/100, worse than 53% of steel grades); weldability poor (32/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 42CrMoS4 Hot Rolled
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 Hot Rolled — frequently asked
What is 42CrMoS4 Hot Rolled used for?
42CrMoS4 Hot Rolled is typically used for shafts, bolts and studs. In short: free-cutting Cr-Mo bar.
What is the yield strength of 42CrMoS4 Hot Rolled?
42CrMoS4 Hot Rolled has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 16 listed tempers.
Is 42CrMoS4 Hot Rolled 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 Hot Rolled be welded?
Not readily — weldability is rated poor (32/100). 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 Hot Rolled?
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 Hot Rolled 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 Hot Rolled?
42CrMoS4 Hot Rolled is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 42CrMoS4 Hot Rolled?
Yes — 42CrMoS4 Hot Rolled 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.