Pitting on the Surface of HIC(Hydrogen Induced Crack) Plates

Pitting or Pitting Corrosion is well known quality failure which we can find on the surface of steel products. Every steel products have stabilized surface which doesn’t response to oxygen or other acidic gas. Harden surface made by heat treatment protects products from those gases. By some reason, however, if surface got damaged, scratch, pock etc the area exposed to O2, H2O, H, then ion responses to those factors and the surface starts to corrode products. Beginning stage, we can’t see any serious damage but scratch. Once it starts to corrode, it’s very fast and losing mass to the direction of gravity. And then it makes hole. More serious problem for HIC (Hydrogen Induced Crack) plates is because its environment of use. In sour service, there is much more acid gas which means that the products can be exposed to severe damage.

pitting surface
Heavy wall products on the its surface during transportation. And the products upper on the plates made some scratches but it wasn’t serious. Couple of weeks later, pitting corrosion was grown.
pitting surface 2
The depth of the corrosion is 0.385mm. Random location.