Steel 42CrMo4 · heat-treated state
Steel 42CrMo4-CH
Properties of the CH condition, compared with the other 42CrMo4 tempers.
Bar hardened and tempered to a specified core hardness band (typically ~280–320 HB), the usual pre-condition before nitriding or induction case hardening.
What is 42CrMo4-CH?
42CrMo4-CH is 42CrMo4 heat treated to CH — bar hardened and tempered to a specified core hardness band (typically ~280–320 HB), the usual pre-condition before nitriding or induction case hardening. 42CrMo4-CH has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi). 42CrMo4-CH 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). HR is the default condition FabDigit quotes; CH is available on request or by drawing note.
Advantages
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited formability — 15/100, worse than 87% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
- Difficult to machine — 40/100, worse than 76% of steel grades
42CrMo4-CH properties
Typical room-temperature values for 42CrMo4-CH — 36 properties are specific to this condition; the rest are grade-level values shared by every 42CrMo4 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
42CrMo4-CH 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
42CrMo4-CH has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
42CrMo4-CH is rated for continuous service to 400°C (752 °F). It conducts heat at 42.6 W/m·K (24.6 BTU/hr·ft·°F), better than 50% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
42CrMo4-CH conducts electricity at 7.8 % IACS, worse than 58% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 42CrMo4-CH takes about 29 MJ of energy and emits 2 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability7
42CrMo4-CH's machinability is fair (40/100, worse than 76% of steel grades); weldability poor (25/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 42CrMo4 tempers and conditions
42CrMo4 is also supplied in 16 other conditions. The full side-by-side table is on the 42CrMo4 overview.
- HRDefaultCheapest stock form for parts that will be heat treated after rough machining.550 MPa yield · 23 HRC
- QT1100Maximum standard Q&T class; highest strength but lowest toughness and highest cracking sensitivity.980 MPa yield · 38 HRC
- Q&TStandard delivered condition for loaded shafts, gears and couplings; best strength/toughness balance.850 MPa yield · 31 HRC
- NitridedChoose for wear surfaces and better fatigue/corrosion on shafts and dies; case is 0.2–0.5 mm deep with a tough Q&T core.850 MPa yield · 31 HRC
- QT1000Higher-strength class for small shafts, pins, high-tensile bolting and connecting rods.820 MPa yield · 34 HRC
- CHBar hardened and tempered to a specified core hardness band (typically ~280–320 HB), the usual pre-condition before nitriding or induction case hardening.800 MPa yield · 31 HRC
- CDBright, close-tolerance bar for turned parts and shafting where no further heat treatment is planned.650 MPa yield · 25 HRC
- NormalizedUniform fine-grain structure for forgings and weld fabrications before final quench and temper.650 MPa yield · 30 HRC
- CRThin strip/sheet form for stamped or formed blanks that are hardened afterwards.480 MPa yield · 215 HB
- SEN 10083 delivery condition treated to a controlled soft structure (≤248 HB) so that bar can be cold-sheared into billets without cracking.450 MPa yield · 220 HB
- AnnealedSoftest condition — pick it for deep machining, cold forming or as a pre-heat-treat blank.415 MPa yield · 13 HRC
- ACAnnealed to globular (spheroidized) carbides for the softest, most ductile structure — the preferred feedstock for cold extrusion, cold heading and deep machining.380 MPa yield · 185 HB
Working with 42CrMo4-CH
Is 42CrMo4 easy to machine?
Machine annealed (≤241 HB) or at 28–32 HRC with rigid setups, coated carbide, 80–160 m/min and generous coolant; above 40 HRC switch to CBN/ceramic or grinding.
Can 42CrMo4 be welded?
Weldable with low-hydrogen consumables but requires 200–350 °C preheat, controlled interpass temperature and post-weld temper at 550–650 °C to avoid HAZ cracking.
Can 42CrMo4 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold forming only in the annealed condition with generous radii — springback and cracking are high at ≥250 HB.
What surface finishes work on 42CrMo4?
No anodizing; protect with black oxide, phosphate + oil, zinc or hard-chrome plate, or nitride; polishes well to a mirror finish in the Q&T condition but rusts if left bare.
42CrMo4 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 | — |
| S42CrMo4; ≤0.005 for 42CrMoS4 grade the range is 0.020–0.040 | ≤ 0.04 | — |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Fe | balance | — |
42CrMo4-CH — frequently asked
What is 42CrMo4-CH used for?
42CrMo4-CH is typically used for drive shafts and axles, gears and pinions, forged industrial parts, hydraulic cylinder rods, high-strength bolts and studs and crankshafts. In short: european Cr-Mo machining bar.
What is the yield strength of 42CrMo4-CH?
42CrMo4-CH has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 17 listed tempers.
Is 42CrMo4-CH easy to machine?
Not especially — machinability is rated fair (40/100, worse than 76% of steel grades). Machine annealed (≤241 HB) or at 28–32 HRC with rigid setups, coated carbide, 80–160 m/min and generous coolant; above 40 HRC switch to CBN/ceramic or grinding.
Can 42CrMo4-CH be welded?
Not readily — weldability is rated poor (25/100). Weldable with low-hydrogen consumables but requires 200–350 °C preheat, controlled interpass temperature and post-weld temper at 550–650 °C to avoid HAZ cracking.
What surface finishes work on 42CrMo4-CH?
No anodizing; protect with black oxide, phosphate + oil, zinc or hard-chrome plate, or nitride; polishes well to a mirror finish in the Q&T condition but rusts if left bare.
Can 42CrMo4-CH be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold forming only in the annealed condition with generous radii — springback and cracking are high at ≥250 HB.
What is the maximum service temperature of 42CrMo4-CH?
42CrMo4-CH 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.
What is the difference between 42CrMo4-HR and 42CrMo4-QT1100?
HR is the default condition — cheapest stock form for parts that will be heat treated after rough machining. QT1100: maximum standard Q&T class; highest strength but lowest toughness and highest cracking sensitivity. Yield strength is 550 MPa in HR versus 980 MPa in QT1100.
Can FabDigit make parts in 42CrMo4-CH?
Yes — 42CrMo4-CH is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10083-3 — Steels for quenching and tempering, alloy steels — CEN (2006)
- GB/T 3077 — Alloy structural steels (42CrMo) — SAC (2015)
- ASTM A29/A29M and SAE J404 (4140) — ASTM / SAE (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- 42CrMo4 / 1.7225 alloy steel datasheet — Ovako / Böhler / Dörrenberg (typical mill data) (2023)
- 42CrMo — Mysteel / 1688 (2026)
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.