Here is the link http://www.numismaster.com/ta/numis/Article.jsp?ad=article&ArticleId=3989 and another one http://www.numismaticnews.net/buzz/Steel+To+Make+Coinage+Comeback.aspx
Steel is a bad idea unless it's stainless or some other non-magnetic variety. Magnets are one of the primary means that banks use to filter out non-US coins/tokens in their coin sorters/counters.