remains of tank n' steel vechicles left in desert since WW2 shows little signs of corrosion.why is dat?..pliz?

Answer 1

Corrosion is oxidation of metals; while you'd think it would just require oxygen, water is also needed. Corrosion is electrochemical reactions in aqueous solutions. You need to build up charge on certain areas of the metal, and the more positive areas oxidize or rust. Some of the metal ions dissolve. All this takes some water...

Answer 2

Low humidity and lack of water from rain or otherwise.