During cathodic degreasing and pickling of metals, as well as during metal deposition (e. g. hard chrome plating, galvanizing, etc.), atomic hydrogen is produced which migrates into the base material. There, it can accumulate in structure disorders such as grain boundaries, segregations and inclusions and thus cause a negative change in the mechanical properties of the base material (increasing embrittlement of the base material due to lattice distortion, crevice crack and bubble formation).
To restore the original material properties - e. g. after galvanic coating - the previously absorbed hydrogen must be removed. This is done very easily by heat treatment. This process is also called hydrogen expulsion, dehydrogenation or degassing.