1.7225 - 42CrMo4 - 15 142
Delivery condition
🔹 +A – Soft annealed
Soft annealed condition
Hardness approx. max. 229 HB
Excellent machinability
Suitable for subsequent heat treatment, hardening and tempering
🔹 +QT – Quenched and tempered
Quenched and tempered condition
Strength according to customer requirements
Typically 900–1100 MPa, in special versions up to 1200–1300 MPa
High toughness, ready for immediate use
🔹 +SR – Stress relieved
Used for parts after rough machining
Stable structure, suitable before EDM, grinding and milling with tight tolerances
🔹 +N – Normalized
Uniform fine-grained structure
Improved mechanical properties compared to +A
Suitable for general structural components
🔹 +FP – Ferritic-pearlitic condition, rolled / drawn
Common for bars and profiles
Suitable for standard machined parts that will be further heat-treated
⚙️ Basic designation
Material number (W.-Nr.): 1.7225
EN/DIN: 42CrMo4
ČSN: 15 142 / 15 260
AISI/SAE: 4140, equivalent
🔩 Properties
High strength and toughness after heat treatment
Excellent hardenability, even in larger diameters
Good machinability in +A condition
Good weldability, with preheating of the material
Resistance to wear and dynamic loading
Stable structure after tempering
Good dimensional stability
🧰 Applications
Shafts, pins and tie rods
Gears and pinions
Piston rods and hydraulic components
Rotors and axles
Bolts and studs
Highly stressed machine components
⚗️ Chemical composition
| Element | Content (%) |
|---|---|
| C, carbon | 0.38–0.45 |
| Si, silicon | 0.10–0.40 |
| Mn, manganese | 0.60–0.90 |
| P, phosphorus | ≤ 0.025 |
| S, sulphur | ≤ 0.035 |
| Cr, chromium | 0.90–1.20 |
| Mo, molybdenum | 0.15–0.30 |
| Ni, nickel | ≤ 0.40 |
| Cu, copper | ≤ 0.30 |
🔥 Typical heat treatment
🔥 1. Hardening
Austenitizing temperature: 830–860 °C
Holding time: depending on diameter, approx. 1 min/mm
Cooling: oil recommended, alternatively polymer
Result: hard martensitic structure
🔥 2. High tempering – quenching and tempering
Tempering should be carried out immediately after hardening.
Tempering temperature: 530–680 °C
Duration: 2 hours for smaller cross-sections up to 4 hours
Purpose: achieving the required strength / hardness
Typical results:
| Tempering temperature | Hardness | Tensile strength Rm |
|---|---|---|
| 540 °C | 32–36 HRC | ~1100 MPa |
| 580 °C | 28–32 HRC | ~1000 MPa |
| 620 °C | 25–28 HRC | ~900 MPa |
| 650 °C | 22–24 HRC | ~800 MPa |
🔥 3. Soft annealing, +A condition
Temperature: 680–720 °C
Cooling: slow cooling in furnace or in air
Hardness: max. 229 HB
Used before machining or as delivery condition.
🔥 4. Normalizing
Temperature: 840–880 °C
Cooling: air
Result: fine-grained structure, uniform properties
🔥 5. Stress relieving, +SR
Temperature: 530–650 °C
Used after rough machining or before grinding.
🔥 6. Nitriding, optional
42CrMo4 is also suitable for nitriding at 500–530 °C, achieving surface hardness of 800–1000 HV.
