Hello. There is an adapter here in our workshop for milling holder BT shanks (that converts for example BT-60 to BT-40). We have decided to build a new one according to the sample. The surface hardness is about 60 HRC, we tested the material for analysis and it was 1.8519 (31CrMov9) (nitriding steel). I was thinking whether it'd be possible to replace the material with a more widespread grade (such as 42CrMo4) as the adapter is required to be nitrided. Also, the work-piece is exposed to water-based liquids. Should it be taken as an design consideration for choosing the material and the surface hardening method? Does the more %C in 42CrMo4 (and more reacting tendency with Cr) affect the anti-oxidation properties of the material? If that's so, what about selecting a 420 steel? Is it possible to nitride it?