The stairs are similar to those in the left photo he

http://americansteelonline.com/stair-steel.htm

The four stairs connect a kitchen door to ground level. Foot traffic is
fairly light, mainly one adult.

Over the decades they have been in place they developed some deep rust
pockets. (No part of the stairs or landing has actually rusted through.)
I first powerwashed everything and then scraped with a putty knife.
Finally, I removed most of the remaining rust with several applications
of Naval Jelly.

I'm looking for recommendations for finish primer and topcoat. Rust
Oleum makes oil-based primers and finishes for such use. Any better
products out there?

Thanks,

Ray