21CrMoV5-7, 1.7709, 21CrMoV5-11, 1.8070 Alloy Steel – Chemical composition, equivalent, properties | Alok India

1.7709 Special Steel

Everything You Need to Know About 21CrMoV5-7, 1.7709 Alloy Steel EN 10269: 2013 (E)


1.7709 Structural Alloy Steel Description

1.7709 special steel belongs to the high-temperature boiler steels category created for the energy industry. The 21CrMoV5-7 alloy steel contains Aluminium in its chemical composition making it distinct from other alloy steels. The aluminium present in the chemical composition helps control grain size and to deoxidize. It is important to deoxidize because it helps control the effects of other alloying elements.


1.7709 Alloy Steel Applications 

The 1.7709 alloy steel has a good set of properties that makes it a suitable material to create various products and parts. It can be used in various applications. This includes:

  1. Shaft forgings
  2. Rotors of steam turbines
  3. Reservoirs
  4. Rotor blades
  5. High tensile shafts
  6. Bolts and nuts
  7. Gears
  8. Spindles
  9. Drive gear
  10. Rear-axle


1.7709 Alloy Steel Chemical Composition

The chemical composition of 1.7709 alloy steel is:

1.7709 steel chemical element % present
Carbon (C)  0.17 to 0.25%
Manganese (Mn)  0.40 to 0.80%
Silicon (Si) [Max] ≤ 0.40%
Chromium (Cr)  1.20 to 1.50%
Phosphorus (P) [Max] 0.025%
Sulphur (S) [Max] 0.030%
Molybdenum (Mo)  0.55 to 0.80%
Aluminium (Al) ≤ 0.030%
Vanadium (V) 0.20 to 0.35%
Nickel (Ni) ≤ 0.60%


1.7709 Alloy Steel Heat Treatment

1.7709 steel hot work and heat treatment temperature
Tempering °C Normalising °C Solution Annealing °C Quenching °C
680 to 720 880 to 850 880 to 850 880 to 850 
Air, Oil or Water Air, Oil or Water


1.7709 Alloy Steel Properties

Here are the properties of 1.7709 alloy steel:

  1. Controls grain size
  2. Hardenable


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