42CrMo4 (1.7225) | Forged & Certified
42CrMo4 (1.7225) custom forged as a shaft, ring, disc, or flange: quenched and tempered (+QT) or annealed (+A), as a single piece or small series and always with a certificate.
About this grade
What is 42CrMo4?
42CrMo4 is a low-alloy chromium-molybdenum quenched and tempered steel with material number 1.7225, defined in EN 10083-3. Metal Service Europe supplies 42CrMo4 as open-die forgings and as seamless rolled rings, from single pieces to small series. Internationally, the steel is often compared to AISI/SAE 4140; that designation is similar but not identical, as the limits for carbon, manganese, and chromium, among others, differ.
The combination of approximately 0.42% carbon with chromium and molybdenum gives 42CrMo4 high tensile strength with good toughness after hardening and tempering (+QT). Therefore, it is a widely used choice for medium-sized, heavy-duty components in mechanical engineering, such as shafts, gears, and flanges. The achievable strength depends on the cross-section: up to approximately Ø60 mm, 42CrMo4 hardens fully after oil quenching; for larger diameters, the guaranteed strength decreases step by step.
For parts requiring extensive machining, the variant 42CrMoS4 (1.7227) exists, with a controlled sulfur content and the same mechanical requirements.
| Designation | Value |
|---|---|
| Short name | 42CrMo4 |
| Material number | 1.7225 |
| Standards | EN 10083-3 (succeeded by EN ISO 683-2), EN 10250-3 (forgings) |
| Sulfur variant | 42CrMoS4 (1.7227) |
| US (comparable) | AISI/SAE 4140 |
| UK (comparable) | 708M40, 709M40 |
| Delivery condition | +QT (quenched and tempered), +A (annealed) |
Applications
Applications of 42CrMo4
Drive shafts and gear shafts
Connecting rods
Flanges
Coupling parts
Crankshafts
Gears and pinions
Composition and properties
Composition and properties of 42CrMo4 / 1.7225
Chemical composition
| Element | Weight % |
|---|---|
| Carbon (C) | 0.38 – 0.45 |
| Silicon (Si) | ≤ 0.40 |
| Manganese (Mn) | 0.60 – 0.90 |
| Phosphorus (P) | ≤ 0.025 |
| Sulfur (S) | ≤ 0.035 |
| Chromium (Cr) | 0.90 – 1.20 |
| Molybdenum (Mo) | 0.15 – 0.30 |
Mechanical properties after quenching and tempering (+QT)
| Diameter (mm) | Rp0.2 min. (MPa) | Rm (MPa) | A min. (%) | KV min. (J) |
|---|---|---|---|---|
| ≤ 16 | 900 | 1100 – 1300 | 10 | – |
| 16 – 40 | 750 | 1000 – 1200 | 11 | 35 |
| 40 – 100 | 650 | 900 – 1100 | 12 | 35 |
| 100 – 160 | 550 | 800 – 950 | 13 | 35 |
| 160 – 250 | 500 | 750 – 900 | 14 | 35 |
Minimum values in quenched and tempered condition (+QT) according to EN 10083-3; this standard was succeeded in 2018 by EN ISO 683-2. For forgings with a larger cross-section, the values according to EN 10250-3 or as agreed upon apply.
Heat treatment and processing
Annealed (+A): maximum 241 HBW
Forging from approximately 1050 – 1100 °C, finish forging to approximately 850 °C
Hardening at 820 – 860 °C in oil or water, tempering at 540 – 680 °C
Induction hardening: surface hardness above 53 HRC
Welding only with preheating, controlled interpass temperature, and slow cooling
Our approach
From inquiry to delivery
Inquiry & specification
You send your drawing or specification with delivery condition, dimensions, and quantities. We verify if 42CrMo4 is suitable for the cross-section and the required strength.
Forging and heat treatment
Shape, weight, and specification determine how your piece is forged. We monitor the forging and heat treatment until the end.
Quality control & delivery
Each piece is tested individually and remains fully traceable. You receive the forging rough, pre-turned, or fully machined, along with the material certificate.
Quality
Certification and quality assurance
A pre-turned 42CrMo4 forging is at least ultrasonically tested. Depending on your specification, magnetic particle inspection (MPI), hardness measurements at multiple positions, or a 3D dimensional check follow. We deliver according to EN 10083-3, the successor EN ISO 683-2, and EN 10250-3, or according to your own requirements or those of your end customer, with a 3.1 or 3.2 certificate. You can read about how we inspect under quality assurance.
Available
42CrMo4 available as
The weight per piece can vary from 20 kg to 200 tons; single pieces and small series are common for us. We supply 42CrMo4 as:
Frequently asked questions
Frequently asked questions about 42CrMo4
What is the material number of 42CrMo4?
The material number of 42CrMo4 is 1.7225. Both designations represent the same chromium-molybdenum quenched and tempered steel from EN 10083-3: 42CrMo4 is the short name describing the composition, 1.7225 is the numerical material number. You will see both on drawings and certificates, often supplemented with the delivery condition, such as 42CrMo4+QT for quenched and tempered material. The variant with increased sulfur content has its own number: 42CrMoS4 is 1.7227.
Is 42CrMo4 the same as AISI 4140?
No, 42CrMo4 and AISI 4140 are similar but not identical. Both are chromium-molybdenum steels, with different limits per standard. SAE 4140 requires 0.38 – 0.43% carbon, 0.75 – 1.00% manganese, and 0.80 – 1.10% chromium; 42CrMo4 requires 0.38 – 0.45%, 0.60 – 0.90%, and 0.90 – 1.20%. If the material must comply with both, the overlap applies, such as manganese 0.75 – 0.90%. If 4140 is on your drawing, we will coordinate that in advance.
What is the difference between 42CrMo4 and 42CrMoS4?
42CrMoS4 is 42CrMo4 with a controlled sulfur content of 0.020 to 0.040%. This sulfur makes the steel more machinable, which is beneficial for extensive turning and milling work. The mechanical requirements after quenching and tempering are the same for both versions. You can see on the certificate by the material number which version has been delivered: 1.7225 for 42CrMo4 and 1.7227 for 42CrMoS4.
Up to what diameter does 42CrMo4 harden through?
After quenching in oil, 42CrMo4 hardens fully up to a diameter of approximately 60 mm. For larger cross-sections, the core is no longer fully martensitic and the guaranteed strength decreases: from a minimum 900 MPa yield strength at a maximum of 16 mm to 500 MPa at 160 to 250 mm. For thick shafts and heavy rings, 34CrNiMo6 or 30CrNiMo8 may therefore be the better choice.
When should I choose 34CrNiMo6 instead of 42CrMo4?
Choose 34CrNiMo6 when the cross-section is larger or the toughness requirements are higher. Thanks to 1.30 to 1.70% nickel, 34CrNiMo6 retains more strength in thick parts: at 160 to 250 mm, a minimum 600 MPa yield strength, compared to 500 MPa for 42CrMo4, and an impact value of 45 J compared to 35 J. 42CrMo4 contains no nickel and is therefore often the more economical choice for small and medium-sized parts.
Is 42CrMo4 weldable?
42CrMo4 has limited weldability and always requires a pre-established welding procedure. Due to the carbon content of 0.38 to 0.45%, a hard, brittle structure quickly forms in the heat-affected zone. Preheating, a controlled interpass temperature, and slow cooling are therefore necessary. There is no fixed preheating temperature: it follows from the wall thickness, the welding process, and the condition of the steel—annealed, normalized, or quenched and tempered.
How is 42CrMo4 hardened?
42CrMo4 is hardened at 820 to 860 °C in oil or water and then tempered between 540 and 680 °C; this is called quenching and tempering. For wear surfaces, the steel is also suitable for induction and flame hardening. After induction hardening, the surface hardness is above 53 HRC, while the core remains tough, which works well for bearing seats and gear flanks. Afterward, the surface is typically stress-relieved at 150 to 180 °C.
What are the tensile strength and hardness of 42CrMo4?
That depends on the delivery condition and the diameter. Quenched and tempered, in condition +QT, 42CrMo4 achieves a tensile strength of 1100 to 1300 MPa up to 16 mm, decreasing to 750 to 900 MPa at 160 to 250 mm. In the annealed condition (+A), the hardness is a maximum of 241 HBW; this allows the steel to be machined well and then subsequently quenched and tempered. If you want a hardness value on the certificate, we will establish that in advance.
With what certification do you supply 42CrMo4?
Typically, a 42CrMo4 forging comes with a 3.1 certificate according to EN 10204. This includes the chemical analysis, the heat treatment, and the results of tensile, impact, and hardness tests on test pieces belonging to the forging. If independent inspection is required, a 3.2 certificate is possible, with acceptance by an inspection body such as TÜV, Lloyd's Register, or DNV.
What is the lead time for a forging in 42CrMo4?
The lead time depends on weight, dimensions, and execution. We can deliver certain pre-turned parts within 6 working weeks; for fully machined parts, 8 to 10 working weeks usually apply. Sometimes a grade or diameter is also quickly available from stock. In the quote, we will state a specific lead time based on your drawing and the current production schedule.
In pictures
A selection of our work
Request a quote for 42CrMo4 / 1.7225
Email us your drawing or a short description of the part. You will quickly hear which version in 42CrMo4 is feasible and what the lead time will be.
EN 10204 3.1 certificate
Single pieces and small series
From 20 kg to 200 tons
Rough, pre-turned, or fully machined
Request a quote
Leave your details, and we will contact you shortly.