EN24 – BRIGHT BAR Grade Introduction:
EN24 steel Bright bar is a very high strength steel alloy which is supplied hardened and tempered. The grade is a nickel chromium molybdenum combination – this offers high tensile steel strength, with good ductility and wear resistance characteristics. With relatively good impact properties at low temperatures, EN24 is also suitable for a variety of elevated temperature applications. EN24 sections larger than 250mm may still be available in the quenched and tempered condition, but it should be noted that a fall-off in mechanical properties may be apparent approaching the center of the bar. It is therefore recommended that larger sizes are supplied in the annealed (softened) condition, and that quenching and tempering is carried out after initial stock removal.  This should achieve better mechanical properties towards the core.
EN24 – BRIGHT BAR Grade Application: 
• High strength shafts • Punches & dies • Drill bushings • Retaining rings • Gears
EN24 – BRIGHT BAR Equivalent grades:
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
EN24 – BRIGHT BAR Chemical composition:
The following table shows the chemical composition of EN24 steel:
Element
C
Si
Mn
P
S
Cr
Mo
Ni
Content (%)
0.36-0.44
0.10-0.35
0.45-0.70
0.035 Max
0.040 Max
1.00-1.40
0.20-0.35
1.30-1.70
EN24 Mechanical Properties:
Condition
Tensile
N/mm²
Yield
N/mm²
Elongation
%
Izod
KCV J
Hardness
Brinell
T
850-1000
650
13
35
248-302
U
925-1000
755
12
42
269-331
V
1000-1150
850
12
42
293-352
W
1075-1225
940
11
35
311-375
X
1150-1300
1020
10
28
341-401
Y
1225-1375
1095
10
21
363-429
Z
1550
1235
5
9
444
EN24 – BRIGHT BAR Hardness:
248 – 302
EN24 – BRIGHT BAR Heat treatment:
Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Please consult your heat treatment provider for full guidance on heat treatment of alloy steel.
EN24 – BRIGHT BAR Hardening:
EN24 is supplied  ready heat treated. If further heat treatment is required annealed EN24 should be heated slowly to 830-850°C and after adequate soaking at this temperature quench in oil. Temper as soon as tools reach room temperature. Hardening from a neutral salt bath, will reduce the possibility of scaling or decarburization. Heat to 830-850°C and after equalization quench in oil.
EN24 – BRIGHT BAR Tempering:
Heat carefully to a suitable temperature selected by reference to the tempering chart or table, soak at the temperature for 2 hours per 25mm of ruling section, then all to cool in the air. Tempering between 250-375°C is not advised as tempering within this range will seriously reduce the impact value. The tempering temperature is dependent on the required mechanical properties, the steel can achieve EN24U, EN24V, EN24W, EN24Y & EN24Z.
EN24 – BRIGHT BAR Physical Properties:
Thermal conductivity at °C
W/(m*k)
40.5
20
32.5
350
25.5
700
EN24 Thermal Properties:
Thermal conductivity – 41.9 W/m-°C
EN24  Forging Properties:
Preheat carefully, then raise temperature to 1000-1100°C for forging. Do not forge the steel below 850-1100°C. After forging cool slowly preferably in a furnace.
EN24 – BRIGHT BAR Stress Reliving:
When parts are heavily machined, ground or otherwise subject to cold work, stress relieving will be beneficial prior to hardening. Heat carefully to 650-670°C, soak well before cooling in the furnace or in the air.
EN24 – BRIGHT BAR Normalizing:
1.Nominal normalizing temperature:840-900°C. 2.Hold the temperature for several hours. 3.Cooling in the air.
EN24 – BRIGHT BAR Annealing:
Heat slowly to 840-860°C, soak well and allow to cool with the furnace to 580°C, before withdrawing.
EN24 – BRIGHT BAR Density:
Density – 7840 kg/m3