Remember the coords in survival are the reverse of Dig Deep.
xx, 0, zz is the bottom of the map.
xx, 512, zz is the top of the map.
Titanium is found at depths 60-90%.
So on a new DD map, thats between depth 1845 and 2768 (where 2768 is nearer the bottom).
On survival maps (and creative) thats between 50 - 205 (where 50 is near the bottom).