EN24 steel is a widely used alloy steel for engineering applications where strength, toughness and wear resistance are important. Known for its reliable mechanical properties, EN24 steel is suitable for components exposed to high loads, impact and demanding operating conditions.
For manufacturers and engineers, EN24 steel offers a useful balance between tensile strength, ductility, machinability and durability. EN24T, also known as 817M40T, is supplied in a hardened and tempered condition and is commonly selected for high-strength mechanical components.
What Is EN24 Steel?
EN24 steel is a nickel-chromium-molybdenum alloy steel designed for demanding engineering applications. It is a through-hardening grade, meaning its properties develop throughout the section rather than being limited to the surface.
The modern designation associated with EN24 is 817M40, while EN24T refers to the hardened and tempered condition. The grade is also associated with 34CrNiMo6 and steel number 1.6582, but always check equivalent grades against the required specification before substituting.
EN24 Steel Properties
EN24 steel’s properties make it suitable for components where reliability and mechanical performance are important. Its alloying elements contribute to hardenability, strength and toughness.
There are a number of significant properties of EN24 steel:
- High tensile strength
- Good toughness and ductility
- Good wear resistance
- Good impact resistance
- Suitable machinability in the appropriate condition
- Good hardenability
- Reliable performance under demanding mechanical loads
- Suitability for heat treatment
EN24T can provide tensile strength of up to around 1000 N/mm², depending on the specified material condition and requirements.
Strength and Toughness of EN24T
Strength and toughness are important when selecting steel for shafts, gears, fasteners and other load-bearing components. EN24T is designed to provide a strong combination of these characteristics.
Its nickel, chromium and molybdenum alloying elements contribute to hardenability and mechanical performance. This allows EN24T to perform effectively in components exposed to high loads, shock loading, torque and repeated mechanical stresses.
Machinability of EN24 Steel
Despite its high-strength characteristics, EN24T offers good machinability when supplied in the appropriate condition. This makes it practical for producing accurately machined engineering components.
The material can be used for turning, drilling, milling and other machining processes, although suitable tooling and machining conditions should be selected according to the material condition and component requirements. Good machinability can also help manufacturers maintain dimensional accuracy while reducing unnecessary production difficulties.
Wear and Impact Resistance
Wear resistance is another important characteristic of EN24 steel. Components used in industrial machinery can experience friction, repeated movement and mechanical loading, so resistance to wear can contribute to service performance.
EN24T also provides good shock resistance, making it suitable for parts subjected to sudden or changing loads. This combination of wear resistance and toughness is particularly useful in heavy-duty engineering environments.
Common EN24 Steel Applications
EN24 steel is used in a range of mechanical and industrial applications that require high-strength alloy steel. Common applications include:
- Transmission shafts and drive axles
- Heavy-duty gears and pinions
- High-strength studs, bolts and fasteners
- Crankshafts and couplings
- Tool holders and engineering fixtures
- Spindles and splined shafts
- Pump rods
- Aerospace and landing gear components
The grade is also used across automotive, aerospace, offshore and general engineering sectors because of its combination of strength, toughness and wear resistance.
EN24T Heat Treatment
Heat treatment plays an important role in achieving EN24 T’s required mechanical properties. The T condition means that the steel has been hardened and tempered, providing a useful combination of strength and machinability.
Depending on the application, EN24 can also undergo processes such as annealing, normalising, stress relieving or additional surface hardening. Consider flame and induction hardening where greater surface hardness and wear resistance are required.
Always select heat treatment based on the component design, required hardness, and intended operating conditions.
EN24 Steel Forms and Supply
EN24T is available in several forms to support different manufacturing requirements. These include bright drawn bar, hot rolled bar, turned and polished bar, and forged blocks.
Material can also be cut to length to suit production requirements. Choosing the right steel form can reduce machining requirements and make the material better suited to the intended manufacturing process.
EN24 Steel Standards and Equivalents
EN24T is associated with the 817M40 designation under BS 970. It is also commonly referenced alongside other international designations.
Relevant designations include:
- 817M40 – associated with the British Standard designation
- 34CrNiMo6 – European designation
- 1.6582 – Werkstoff number
- AISI 4340 – international designation
- ASTM 4340 – international specification
Always check equivalent grades carefully before substitution. Chemical composition, mechanical properties, certification and applicable standards can vary, so the required specification should be confirmed for each application.
Choosing EN24 Steel for Engineering
EN24 steel can be a suitable choice when an engineering component requires high strength, toughness, wear resistance and reliable machinability. Its performance makes it particularly relevant to shafts, gears, fasteners, tooling and other components exposed to demanding mechanical conditions.
For projects requiring EN24T or 817M40T, Midland Special Steels supplies the grade in different bar and forged forms, with services including cutting to length, centreless grinding, heat treatment options and non-destructive testing. Material certification and traceability are also available for applications where specification control is important.
