Northern's spray pickling booth allows us to restore the corrosion resistance of stainless steel after all welding and fabrication is completed. Our spray picking booth is one of the largest in the country.
Very large assemblies can be cleaned in a few hours. Mechanical grinding or acid washing (local electropolishing) requires many labor hours.
Other cleaning methods such as mechanical grinding or blasting are prone to corrosion issues. Electropolishing and Pickling completely restores the base metal's corrosion resistance.
Pickling is the best process to completely clean the entire surface of your product. However, the chemical and waste disposal costs are high. Depending on the environment, your product may not require pickling to meet quality expectations.
Mechanical grinding with abrasives, sand blasting, or a wire brushing can remove material affected by high welding temperatures. Care must be taken to keep tools clean from iron, or else the cleaning may instead spread iron contamination everywhere. The manufacturing planning must also be precise, as any contamination from handling (scratches, etc) will not be cleaned in this process.
Electropolishing attacks and removes oxides and the corrosion prone chromium depleted layer. During the process, electropolishing can also leave a smoother surface, further improving corrosion resistance. The selective cleaning and reduced roughness leaves optimal corrosion resistance.
Electropolishing can be accomplished through a dip process on small parts, or through local cleaning on large parts called acid washing. Because most large welded parts are too large to fit into an electropolishing tank, local cleaning of welded areas is often used. This fully repairs the welded areas, but doesn't decontaminate the entire surface of the product.
Best: Spray Pickling & Passivation
Spray pickling is the most common chemical process to remove oxides and iron contamination. It cleans the entire surface of organics (oils, greases), welding oxides, and iron contaminants. Spray pickling is the best choice when the corrosion resistance requirements are essential to the product's quality.
Spray Pickling and Passivation Photo Gallery
Northern Manufacturing is a sheet metal fabrication company specializing in stainless steel fabrication.