Chromium added to steel does not
Chromium forms a very thin, transparent, adherent layer of Cr2O3 through a process called passivation, which provides a barrier to diffusion of oxygen and other corrosive species and it prevents further corrosion of the underlying alloy.
Ref: Phillip’s 12th edition page 127.
Increase hardness
Increase tensile strength
Increase corrosion resistance
Decrease elastic limit