Being used for crafting almost anything, steel may be the most important material when it comes to advanced technology. Getting steel is the very first step to start the atomic age - everything needs better and tougher parts.
Steel can be made with the alloy furnace by combining coal with iron, this will give you two ingots of steel. Additionally, steel can also be found in abandoned structures such as radio stations and nuclear power plants - they don't need it anymore, right? Right?
Steel is most commonly used in the form of plates - cells, machine casings, bomb bodies, and grenades are made from it. Pure ingots can be used for crafting various deco elements such as scaffolds and thin walls and for crafting armor and tools. Steel tools will last twice as long as iron tools and mine blocks a little bit faster.