1.7225 | 42CrMo4 +QO +T Hardened and tempered (quenchant: oil)
| Numeric designation | 1.7225 |
|---|---|
| Chemical designation | 42CrMo4 |
| State | +QO +T Hardened and tempered (quenchant: oil) |
| Etching | 3% Nital |
This hypoeutectoid steel (bar stock with ⌀ = 28 mm) with 0.38 % carbon (measured by OES; nominal: 0.38 – 0.45 %) was austenitized at 850 °C for 30 min, quenched in oil and then tempered at 250 °C for 2 hours.
The microstructure is completely martensitic both at the edge and in the core; due to the carbon diffusion-inhibiting alloying elements, the critical cooling rate was also reached in the core of the specimen. At low magnification, dendric superstructures from the initial state can still be guessed at.
The average hardness is 595 HV5.
