Polyester Primers
Check the P sheet on them. I know I was doing some research on these Evercoat listed one that was corrosion resistant. That's what you want on bare steel. If you want you could spray an epoxy primer first then your poly primer for your corrosion protection. Poly primers are damn thick and sometimes can crack if you don't sand enough of it off. If you plan on using them I would consider board sanding it down very flat with 180, to get it really straight, then follow with a little 2k to fill those scratches.