During the manufacturing process of stainless steel equipment, performance damage, defects, and some substances that affect the surface, such as: dust, floating iron powder or embedded iron, thermal tempering color and other oxide layers, rust spots, grinding burrs, welding arc marks, welding Spatter, flux, welding defects, oil and grease, residual adhesive and paint, chalk and marking pen prints, etc. The overwhelming majority are because they ignore their harmful effects and do not pay attention to it or do it poorly.
However, they are potentially harmful to the oxidation protective film. Once the protective film is damaged, thinned or changed by other methods, the stainless steel below will begin to corrode. Corrosion is generally not spread over the entire surface, but at or around the defect. This kind of local corrosion is usually pitting corrosion or crevice corrosion, these two kinds of corrosion will develop in depth and breadth, and most of the surface is not corroded.