zOwie Omega Discussion Forum

: Don't forget that how metal is worked into
: shape has a lot to do with it's hardness.
: For instance, Stainless clasps that are
: stamped tend to be "work hardened"
: and don't scratch as easily as stainless
: clasps that are tooled (cut) from a solid
: piece. In addition, titanium nitrate that
: forms as a coating is very hard, the
: titanium underneath is softer. Citizen
: titanium "duratect" is specially
: treated to be almost scratch proof. Just my
: $.02

: -Mitch

You raise an important point by bringing up work hardening. I think here is the way to optimize it. If you machine the watch case from a solid block, that block can be made from an extensively cold rolled piece of plate. So the work hardening is maximized during the rolling. If you bend thin sheet to attempt to achieve work hardening while forming it, you have to start with a relatively soft, not work hardened material to avoid cracking the bent regions. The problem is that only the deformed part of the metal gets work hardened. That is, the curved, bent part does and the flat regions don't. So I think you're better off with the machining of a highly cold rolled plate.

Another way you can get into trouble is with the unintended anneal which will happen duriing brazing. I understand that the Rolex band is hollow to save weight (never mind that it uses less gold). Brazing the sides onto each link anneals the material cancelling out the effects of the plastic deformation. That should make it dead soft for that alloy.

Finally, I belive you mean titanium nitride, TiN, which should be nice and hard and is the way we often get "goldtone". It may be transparent when it is thinner but I'm not sure of that.