Steel rusts when exposed to air. Appliances are generally coated with a very durable porcelain enamel that should prevent this. If that surface was scraped up it exposes the steel.
The other possibility is high levels of moisture that promote a kind of surface rust -- if this is due to being in a damp basement you might investigate ways to reduce that moisture.
In either case the cure is to remove the rust and apply new layer of coating(s), sadly they won't hold up as well as factory finish that likely was "catalyzed".
https://www.prettyhandygirl.com/how-...ed-appliances/ The factory likely used something like this --
https://www.all-spec.com/Catalog/Adh...iABEgKmMfD_BwE Unfortunately once rust attacks steel it is not really possible to repair all the damage and subsequent applications of even catalyzed polymer coatings likely will fail --
https://www.sciencedirect.com/scienc...10938X9390037H
Even "stainless steel" can rust -- this is especially true if it is too vigorously cleaned --
https://refrigerators.reviewed.com/f...sumers-rattled