You need to research the item before you can make it. In the chemistry building (not sure about NU but in Sar anyways) on the table you will find the research lab. All the items you can craft are listed there.
Once you find steel you can put it what would be the correct amounts needed to make steal and research it. Once researched you can then make it normally.
If you want to know the correct ingrediants
http://wiki.afterworld.ru/wiki/Steel
Research is also used to gain skill. but that is whole other thing.