5. Hydrogen and paint stripping

In the course of its metallurgical history, during processing and in use, a metallic material such as steel is subjected to various sources of hydrogen. For the record, a "finished" part has undergone hydrogen-generating chemical and/or electrolytic treatments during its transformation. While the volume of hydrogen produced can be reduced, it cannot be totally avoided during so-called "preparation" chemical and/or electrolytic treatments, such as cathodic degreasing or acid pickling, nor during any subsequent electroplating or conversion phase. Consideration of the preparation sequence shows that anodic alkaline degreasing, between acid pickling and electroplating proper, oxidizes the hydrogen occluded in the subsurface after pickling, thereby minimizing metal sensitivity prior to deposition.

Hydrogen-steel interaction can cause significant material degradation...