Steel Ingots, added by the Mekanism Mod, the RailCraft Mod as well as the Basic Components, are a staple to most of the items that may be crafted in this ModPack. Within Voltz there are 3 different ways to craft Steel Ingots. Unfortunately this means that there are 3 different types of Steel Ingots that one could make. Foutunately all forms of Steel are interchangeable throughout every crafting recipe.
Beware there are some differences in the ingots and some bugs with the crafting recipes related to steel, for instance there are two different looking types of steel blocks with one coming from Railcraft and one coming from Basic Components. So if your crafting recipe isn't working I would recommend getting the steel from the mod of whatever you are trying to craft and seeing if that works.