forge+1 and mastery Increase damage value?

or Formula

Damage = Base Damage * Mastery / 1000
For example base damage = 608, mastery = 1423, then damage = 608 * 1.423 = 865
You can see your base damage value when you move cursor to your weapon's icon.
Same with all damage dealing skills and with healing, and with amount of HP of dwarf's buildings.

～ty

forge upgrade +1 Increase damage value？

Not sure I understand you correctly. You mean upgrading armor/weapon in forge?

If so, then yes. But partly. Each time when you successfully upgrade an item, it gives health or mastery bonus (it's random). So if you get mastery bonus, your damage will slightly increase.