Surface treatments for 90° equal diameter elbows of 304 stainless steel pipe fittings offer various options to enhance their corrosion resistance, aesthetics, and mechanical properties, adapting to the needs of different industrial applications. Mechanical polishing, as a basic treatment, uses tools such as grinding wheels and polishing wheels to grind the surface of the 90° equal diameter elbow, effectively removing burrs, scratches, and oxide layers, achieving a certain level of surface smoothness. While simple to operate, its final smoothness is often limited by tool precision, making it suitable for cost-sensitive applications with less stringent surface requirements.
Electrolytic polishing, on the other hand, uses an electrochemical reaction and an electric current in an electrolyte to remove microscopic surface imperfections, forming a uniform metal oxide film. This method significantly improves surface smoothness and enhances corrosion resistance, making it particularly suitable for piping systems with high hygiene requirements, such as those in the food and pharmaceutical industries. It offers high processing efficiency and low environmental pollution, but requires relatively high equipment costs and process control.
Pickling and passivation is another common surface treatment method. It removes oxide scale, oil, and impurities from the surface of a 90° equal diameter elbow through a chemical reaction, while simultaneously forming a dense passivation film. This film effectively isolates corrosive media, extending the service life of the 90° equal diameter elbow. Pickling and passivation is suitable for industrial pipelines requiring enhanced corrosion resistance, especially for applications where oxide discoloration needs to be removed from weld areas after welding. The treatment method is flexible, employing methods such as immersion, paste application, and spraying to adapt to the treatment needs of 90° equal diameter elbows of varying batches and shapes.
Sandblasting, on the other hand, involves high-speed jetting of abrasive materials (such as copper ore sand or quartz sand) onto the surface of the 90° equal diameter elbow to remove oxide scale and impurities, while simultaneously creating a certain surface roughness. This method not only cleans the surface but also allows for the creation of different surface textures by adjusting the abrasive particle size and blasting pressure, meeting specific decorative or functional requirements. After sandblasting, the adhesion of the 90° equal diameter elbow surface is enhanced, providing a good foundation for subsequent coating treatments.
Bright annealing involves high-temperature heat treatment of a 90° equal diameter elbow under hydrogen or vacuum conditions to eliminate internal stress and form a passivation film, improving surface quality. This method is suitable for 90° equal diameter elbows requiring high surface finish and corrosion resistance, especially in applications where material properties need to be restored after cold working. After bright annealing, the surface of the 90° equal diameter elbow exhibits a uniform metallic luster, and the internal structure is more stable.
Surface coloring treatment uses methods such as chemical oxidation, electrochemical oxidation, or ion deposition to form a colored oxide film on the surface of the 90° equal diameter elbow. This film not only enhances the aesthetics of the 90° equal diameter elbow but also strengthens its wear resistance and corrosion resistance. Surface coloring can be customized to meet individual needs and is widely used in architectural decoration, art production, and other fields.
Furthermore, PVD (Physical Vapor Deposition) technology, as an advanced surface treatment technology, uses physical methods to spray special-performance microparticles onto the surface of the 90° equal diameter elbow, forming a high-strength, wear-resistant, and corrosion-resistant protective layer. This method is particularly suitable for applications with extremely high surface performance requirements, such as marine engineering and chemical equipment. PVD-treated 90° equal diameter elbows exhibit high surface hardness, low coefficient of friction, and a variety of colors to meet the needs of different environments.
