Steel grade 42CrMo4 is a medium-carbon alloy structural steel specified under the EN 10083 standard. It is well-known for its excellent overall mechanical properties and good hardenability, and is widely used across the mechanical engineering industry. Typical applications include the manufacture of critical load-bearing components such as shafts, gears, connecting rods, and high-strength bolts.
Within the EN 10083 standard, 42CrMo4 is classified as a grade for quenched and tempered steels. The standard precisely defines its chemical composition range and corresponding hardenability classes. To meet different application requirements, 42CrMo4 is further categorized into three levels—H, HL, and HH—providing a reference for both procurement and design selection.
For impact toughness testing, the standard requires the use of Charpy V-notch specimens. Due to the significant stress concentration at the V-notch, the specimen becomes highly sensitive under impact loading, allowing a more accurate assessment of the material’s toughness. Furthermore, EN 10083 specifies the required mechanical properties and recommended heat treatment conditions for 42CrMo4.
In terms of internal quality, the standard outlines requirements and inspection methods for non-metallic inclusions to facilitate negotiation between suppliers and customers. However, it does not set explicit requirements for macrostructure (low magnification structure). Regarding grain size, the standard mandates that the grain size must be finer than or equal to Grade 5, and it provides corresponding testing methods and recommended quenching conditions.
The standard offers five different delivery conditions for 42CrMo4:
- Without heat treatment requirements;
- Heat treated to improve machinability;
- Soft annealed delivery condition;
- Quenched and tempered technical condition (QT);
- Other heat treatment technical conditions as agreed between supplier and customer.
Overall, the EN 10083 standard provides a clear and professional technical framework for the ordering, application, and inspection of 42CrMo4 steel, supporting its widespread use in the manufacture of high-performance mechanical components.
Post time: Apr-30-2025
