EN 24 Material
EN24 is a popular grade of through-hardening alloy steel due to its excellent machinability in the "T" condition.
EN24T is used in components such as gears, shafts, studs and bolts. EN24T can be further surface-hardened to
create components with enhanced wear resistance by induction or nitriding processing.
International Steel Specification Comparison (EN24T)
BS 970:1955 EN24T
BS 970:1991 817M40T
German / DIN 34CrNiMo6
French AFNOR 35NCD6
American AISI / SAE 4340
German Werkstoff No. 1.6582
European Standard EN10277-5
Typical chemical composition of En24
C SI MN S P Cr Mo Ni
0.36/0.44 0.10/0.35 0.45/0.70 0.040 max 0.035 max 1.00/1.40 0.20/0.35 1.30/1.70
Used in construction of aircrafts and heavy vehicle for crankshaft, gearshaft, camshaft, propellershaft etc
Carbon(C) Directly influences the hardness and strength of the steel, decreases toughness.
Chromiun(Cr) Improves Hardenability, high temperature strength, wear resisitance and even corrosion
Cobalt(Co) Improves retention of hardness at high temperatures.
Molybdenum(Mo) Increases yield point and strength. Improves Hardenability and wear resistance. Manganese
Lowers effects of Iron sulphides, increases hardenability, wear resistance.
Nickel(Ni) Increases toughness at lower temperatures, slows the corrosion process. Improves toughness,
grainstructure, high temperature strength, wear resistance, etc.
Vanadium(V) Increases wear resistance, high temperature strength, retention of hardness etc.
Silicon(Si) It is a deoxidizing agent. Increases strength and wear resistance. It is of importance that certain
elements are as low as possible. Elements like Hydrogen, Oxygen, Nitrogen, Phosphorous, Sulphur create defects
inside & also reduce the mechanical properties of steels.
Hardening: Heat uniformly to 823/850C until heated through. Quench in oil.
Tempering: Heat uniformly and thoroughly at the selected tempering temperature, up to 660C and hold at heat for
two hours per inch oftotal thickness. Tempering between 250-375C in not recommended as this can seriously
reduce the steels impact value.
Heat slowly to 650-670C, soak well before cooling the EN24 tool in a furnace or in air.
Tensile Yield Proof
Heat a% on Impact Impact Hardness Size
Strength Stress Stress
Treatment 5.665ÖSo Izod J KCV J HB mm
Rm N/mm² Re N/mm² rp0.2
T 850/1000 654 13 40 35 635 248/302 >150≤250
T 850/1000 680 13 54 50 665 248/302 >63≤250
U 925/1075 755 12 47 54 740 269/331 >29≤100
V 1000/1150 850 12 47 42 835 293/352 >13≤63
W 1075/1225 940 11 40 35 925 311/375 >6≤29
X 1150/1300 1020 10 34 28 1005 345/401 >6≤29
Z 1550 1235 5 10 9 1125 444 >6≤29