Annealing should be done in a vacuum or gas protected environment if
you make aero planes or rockets.
For Jewelry titanium has enough strength so if some oxides or
hydrogen gets in the metal is for us jewelers no problem.
You can anneal up to dull red. (650 degree Celsius) This is enough
to make titanium (grade 1,2,3) soft again. You will get a rather
thick oxide layer you have to grind or etch of.
Also when you want to deform heavily you can heat up the titanium an
easy bend or forge it etc. When I make tension rings I heat up the
wire to wrap it around a coil.
compositions in precious metal
8041 AK, Zwolle