Pickling and passivation of Stainless Steel Pipes are two forms of chemical metal finishing that provide protective properties to metal especially against rust. Actually,pickling and passivation refers metal submerged in a bathing liquid that removes imperfections and rust from the surface of stainless steel.Where the steel has been heated by welding, or other heat treatments,to the point where a coloured oxide layer can be seen, there is a chromium depleted layer on the surface of the steel underneath the oxide layer.
Pickling and Passivation of Stainless steel Pipes owes its varied application to its natural corrosion resistance, or passivity. Passivity is bestowed on the material by the formation of an extremely thin and complex surface oxide layer. The layer itself is vulnerable to damage from manipulation of the material during processing, fabrication and even transport. The result is a loss of passivity at damaged areas, with a reduction in corrosion resistance as a consequence. Surface damage of stainless steel can lead to unexpected corrosion.
“Passivation and Pickling are often used together on equipment to remove all contaminates and oxidation, improving the corrosion resistance, extending the life and overall value of your components.”
To restore the best corrosion resistant performance, the damaged metal layer must be removed, exposing a fully alloyed stainless steel pipes surface. Mechanical removal may leave abrasive or other particles embedded or may be impractical sometimes.Chemical treatments that are correctly performed can clean the surface and ensure the best possible corrosion performance.