It would appear from your picture that you only have light surface rusting. is this inside a building?
It that is the case, wirebrushing or light sandblasting followed by a coating of your choice wuld be in order.
If it is outside, I would suggest sandblasting to remove old paint,checking for pitts in the surface, followed by a clear penetrating epoxy primer, then a 2 part polyurethane coating.
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor