What is the purpose of pickling in metal preparation?

The purpose of pickling in metal preparation primarily focuses on the removal of rust, mill scale, and other surface contaminants. Pickling usually involves the use of an acidic solution that dissolves these unwanted surface layers, effectively cleaning the metal substrate and preparing it for subsequent processes, such as painting or coating.

By eliminating rust and mill scale, pickling ensures that the surface of the metal is smooth and free from materials that could hinder adhesion. This results in a better bond between the metal and any coatings that are applied afterward.

While removing oxidation is a part of what occurs during pickling, it is more accurate to say that pickling targets the broader category of contaminants like rust and mill scale. Other methods might be employed specifically for painting, applying coatings, or treating surfaces, but the essence of pickling lies in preparing the metal by getting rid of surface impurities that could impair durability and performance.