Max damage for each req can be found here. To save you a click, it's 6-24 (or 7-20) for a req 6 axe.
Inherent values are dependent on rarity, not requirement. A x^50 mod on a rare weapon will be either 14^50 or 15^50. The lowest req a max inherent can drop at is the lowest req an item can drop as rare.
Guild Wars Legacy in the WSC-Connect App on Google Play
Guild Wars Legacy in the WSC-Connect App on the App Store