Abstract

The object of this research is to study the passivity of parts surfaces produced from steel and its alloy. The study steps include, preparing specimens of low carbon steel ,with (dimension (20*30 cm) and its thickness (2 mm)). The specimens were immersed in a solution containing the following: 

   Caustic soda.
2.    Sodium nitrate (1%)
3.    Sodium cyanide (1.5%)
4.    Sodium chromate (1.5%)
The influence of caustic soda concentrations, temperature of solution and
time of immersing on corrosion of specimens were studied, from which it has been shown that it was possible to obtain the best passive surfaces of the parts with caustic soda concentration (5%), time  of immersing  specimens (20 min) and temperature of solution (45oC). 
The results and conclusions obtained from this study were applied to treating surfaces of some machining parts in Nasser State Company/central tool room plan. The results  show noticeable improvement in  the corrosion resistance of the metal used for more than 70 days.