Io sapevo che viene fatto con spegnimento in olio e con tabelle un pò divrse
- austenise at 1.050°C, keep it there for at least 15 min.
- quench in oil (preheat oil to at least 70° C)
- cryo treatment in liquid nitrogen, keep submerged for at least 30 min.
Tempering in an oven, let cool down in air
- tempering for 60 min. at 180°C without cryo yields 60 HRc, w/ cryo appr. 61 to 62 HRC.
- tempering for 60 min. at 300°C without cryo yields appr. 54 HRc, w/ cryo appr. 55 to 56 HRC.
If you can't do cryo, please do 3 tempering cycles (200 / 190 / 180° C)
instead of two. Toughness will be similar, hardness a bit less but still
at 60 HRc minimum.