Steel Bars are a critical component of many important workbenches that you may find yourself wanting or indeed needing in the later stages of the game. You also use Steel Bars in the Sandstorm Mask, which allows you to survive noxious fumes and of course, the Sandstorm. Perhaps most importantly, Steel Bars are used to create Steel Reinforcements, which are vital and highly sought-after components of Tier 3 buildings. If you want to access Black Ice, Yamatai, Turanian, and many other indomitable structures, Steel Reinforcements are critical.