@titans62 - I think you may be overstating the importance of joining a steel workers union in order to rise in the profession.
Of course, it does help to join the local union, for a variety of reason, but just because someone is high up in the local union does not mean that they will get a better job in the steel industry.
Most of the steel unions that I know of have one of their own as the head of their local union, thus another steel mill worker. I doubt someone looking to do something else in the industry would want to be the union head of a low level job in the industry, hoping that it will transfer them somewhere else.
I believe that it all depends, like in any other job, how far you go in the industry and what you are qualified and trained for. There are appropriate channels to go to for this, the unions are one of them and definitely something to consider in the steel industry, but it is definitely something that is more of who is better qualified than anything as opposed to political reasons.