NITRIDING ENGINEERING STEEL
Benefitting from good wear resistance and high fatigue strength, EN40B (722M24) is a chromium-molybdenum based engineering steel grade which is often supplied in the hardened and tempered condition. This can promote a tensile strength of up to 1075 N/mm². Nitriding produces a hard and wear resistant casing resulting in an engineering material which offers good fatigue and shock resistance. The nitriding process is normally performed at a relatively low temperature which results in a scale free surface with minimal distortion. EN40B (722M24) can operate in atmospheres of up to 500°C before any loss in surface hardness is observed. EN40B is supplied in the hardened and tempered ‘T’ condition. This nitriding steel also offers a good combination of ductility and toughness. When supplied in the ‘T’ condition, EN40B is ideal for applications requiring high tensile strength and high creep resistance.
EN40B (722M24) has become a popular engineering material for use in industries such as textiles, automotive and aerospace. It is also used extensively by billet crankshaft manufacturers.
BENEFITS OF NITRIDING & CARBURISING
Both heat treatments are thermomechanical and performed at low temperature which promotes minimal distortion. Nitriding promotes a high surface hardness with resistance to wear and galling whilst fatigue strength is also increased. Carburising is a thermomechanical heat treatment which diffuses carbon in the surface of the steel creating a hard casing. This increases the overall strength of the material and promotes increased wear resistance. EN40B (722M24) is particularly suited to both heat treatment types which results in a high strength, high wearing engineering steel.
The welding of EN40B (722M24) is not recommended but it is readily machinable using conventional machining methods and in accordance with the machine manufacturer's instructions.
EN40B (722M24) is supplied in the ‘T’ condition. Commercial application examples include:
- Crankshafts and gears
- Compressor discs
- Cams, pinions and gudgeon pins
- Spindles and pins
- Gear wheels
- Used in aerospace, textile, automotive and general engineering applications