and great watch.
Black power, indeed.
Welcome here...
Best.
Emilio.
hope the following is useful,
I got these spec from my u-black operating manual:
CASE:
-tempered submarine steel, black hard coated with a hardness of 1500 HV
- hardened diver's bezel with lumnous triangle, ....
also got these info for the black u-series from an AD's site,
Standard steel used by most watch companies has a hardness of between 200 and 240 HV (Hardness Vickers is a common scale used to measure material hardness). The Tegiment layer on this watch in combination with the PVD coating has a hardness in excess of 2,000 Vickers which is more than nine times harder than standard steel.
The Tegiment layer is not a coating consisting of a foreign material, instead the steel itself that has been hardened using a special engineering process that creates a hardened barrier. This process increases the submarine steel's resistance to corrosion, as well as provides extreme protection from scratches and other damage to the case.
The Tegimenting process also acts to harden the black PVD treatment on the case