Chemical Descaling
Chemical descaling dissolves high-temperature oxides on the metal surface using strong acidic or alkaline baths, preparing the surface for subsequent passivation.
Physicochemical mechanism of action
Chemical descaling refers to the process where high-temperature-generated oxides on the metal surface are dissolved by strong acidic or alkaline solutions. This process removes the oxides and prepares the surface for subsequent passivation.
Metallurgical relevance & risks in welding
Chemical descaling is crucial to prevent porosity and corrosion. Without adequate descaling, oxides can remain on the surface, leading to poor weld joints and reduced component life. Over-descaling can damage the metal structure and impair strength.
Workshop practice & instructions
For chemical descaling, a suitable descaling bath is used, e.g., an acid or alkali solution. The metal parts are immersed in the bath and held for a specific time (typically 5–10 minutes). After descaling, the surface is wiped clean and dried before passivation.