A list of all* the artifacts
in case you want to reroll to get the 1 you want
Level 1 : +2 Minimum Damage
Level 2 : +5 Minimum Damage
Level 3 : +9 Minimum Damage
Level 4 : +15 Minimum Damage
Level 5 : +25 Minimum Damage / +10% Min. Dmg. of Max Dmg.
Sledge Hammer
Level 1 : +20 Armor Penetration
Level 2 : +40 Armor Penetration
Level 3 : +60 Armor Penetration
Level 4 : +80 Armor Penetration
Level 5 : +100 Armor Penetration / +10% Maximum Damage
Binoculars
Level 1 : +4% Double Scrap Piles
Level 2 : +8% Double Scrap Piles
Level 3 : +12% Double Scrap Piles
Level 4 : +16% Double Scrap Piles
Level 5 : +20% Double Scrap Piles / +2% Golden Scrap Piles
Level 2 -> Level 3 = 5 Refined Materials
Level 3 -> Level 4 = 10 Refined Materials
Level 4 -> Level 5 = ? Refined Materials
Thanks to No Game No Life for his great guide, all credit to his effort. you can also read the original guide from Steam Community. enjoy the game.