Question

iron articles rust readily whereas steel which is also mainly made of iron will not undergo corrosion​

Answer 1

iron when it comes in contact of the atmosphere it get rested easily but steel which is made up of iron is also a micture of some other metals therefore it becomes resistant to corrosion and hence do not undergo corrosion easily.

Answer 2

presence of Chromium in steel hinders the oxidation of Fe. so, steels don't corrode or undergo very little corrosion or corrosion process is slow.