1.7225 Steel for quenching and tempering

Designation

Chemical composition:

Strength:

max. 217 HB
(≈ max. 740 N/mm²)

Tensile strength:

heat treated max. 720 N/mm²

Thermal conductivity at 20 °C:

42.6 W/m K

Character:

alloyedsteel, suitable for quenching and tempering, steel with high resistance and high toughness;
universally usable in engineering

Application:

machine construction, base plates, axes, gear shafts, gear wheels

Treatment by

is possible:
Nitriding, EDM, coating

unusual:

Welding

Heat treatment:

Normalising:
840 to 880 °C afterwards cooling in air; some components need tempering afterwards

Soft annealing:
680 to 720 °C for about 2 to 5 hours; slow controlled cooling of 10 to 20 °C per hour to about 600 °C; further cooling in air. Maximum 217 HB

Quenching:
max. 1.600 N/mm²

Hardening:
820 - 880 °C
quenching in oil or water
oil hardening for thin and complex,
water hardening for large and simple components
obtainable hardness: 53-61 HRC

Tempering:
slow heating to tempering temperature (to avoid forming of cracks) immediately after hardening; at least 60 minutes cooling in air

Annealing graph:

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