Passivation as a Technique for Restoring Corrosion Resistance in Stainless Steel

14 January 2019
 Categories: Industrial & Manufacturing, Blog

When working with stainless steel, the metal surface can easily become stained, corroded or contaminated. Processes such as welding (and other fabrication techniques) may expose the metal to external elements that interfere with its overall chemical composition.

Passivation, also called spray pickling, is a useful technique that can be used to restore a stainless steel surface. The process involves spraying a protective layer that removes oxides, iron ore contamination and oils from the surface of the metal. Spray pickling can remove harmful contaminants from a stainless steel surface so as to reinforce corrosion resistance.

Benefits of Spray Pickling

During stainless manufacturing, the equipment and processes used can result in contamination of the stainless surface. For example, welding tends to create oxides and iron ores that can affect the quality of metal moving forward. After a weld, these surfaces need to be electro-polished or grinded to remove such oxides. Iron ores and oxides also speed up the corrosion process and can affect your final product.

Spray pickling is a more effective alternative to electro-polishing or grinding. Using a pickling spray, the process involves applying a coating that removes corrosive products, welding scale and annealing colours. Spray pickling also cleans the surface of oil and dirt. In this way, the technique can restore corrosive resistant properties that may have been removed during fabrication. Spray pickling can also be used for batch processes, which makes it more efficient than electroplating.

Another benefit of spray pickling is that it results in minimal emissions of nitrous gases. You can restore the bright and polished look of your stainless steel surfaces without worrying about inhaling poisonous gases.

Spray pickling in action

Many different industries are taking advantage of spray pickling. From HVAC equipment to vehicles and pipes, the process comes in handy when polishing and infusing corrosive resistance in stainless steel components. For example, power generation plants rely on spray pickling to coat their infrastructure and remove contaminating oil and grease. And because the process can be done on a large-scale basis, large power generating machines can be coated and cleaned in a timely fashion.

Metal beams used in construction also benefit from spray pickling. These stainless steel beams may be used to add stability to a structure or to provide a working platform for construction personnel.

Regardless of their specific purpose, spray pickling is often used to remove welding oxides after the fabrication process. In addition, the technique also prevents iron ores and organic oils from contaminating the beams used to provide structural support.