Common surface treatment methods of stainless steel threaded flanges

　　The surface treatment technology of stainless steel threaded flanges commonly used has the following treatment methods:

　　1. Surface whitening treatment: During the processing of ANSI 1500LB Stainless Steel Threaded Flange, black oxide skin is produced by rolling, edge-binding, welding or artificial surface heating treatment. This kind of hard gray-black oxide skin is mainly composed of NiCr2O4 and NiF EO4, which were usually removed by strong corrosion with hydrofluoric acid and nitric acid before. But this method is expensive, polluting the environment, harmful to human body, corrosive and gradually eliminated. At present, there are two main methods to treat oxide skin:

　　(1) Sandblasting (pellet) method: mainly using the method of spraying glass beads to remove the black oxide skin on the surface.

　　(2) Chemical method: A non-polluting pickling passivating paste and a non-toxic cleaning solution with inorganic additives at room temperature were used for leaching. Thus the whitening treatment of stainless steel threaded flanges is achieved. After treatment, it basically looks like a dull color. This method is more suitable for large and complex products.

　　2. Mirror gloss treatment of stainless steel threaded flanges surface: According to the complexity of stainless steel threaded flanges products and different user requirements, mechanical polishing, chemical polishing, electrochemical polishing and other methods can be used to achieve mirror gloss. The advantages and disadvantages of these three methods are as follows:

　　3. Surface coloring treatment: stainless steel threaded flanges coloring not only gives stainless steel threaded flanges products a variety of colors, increase the variety of products, but also improve the wear resistance and corrosion resistance of products.