Floating rust on pipes

Surface whitening treatment to reveal the natural color: During the processing of stainless steel, processes such as rolling, edge bonding, welding, or manual surface heating can result in the formation of black oxide scales. These hard, grayish-black oxide scales are primarily composed of NiCr2O4 and NiF2. In the past, strong corrosive agents such as hydrofluoric acid and nitric acid were used to remove these scales. However, this method is costly, environmentally harmful, toxic to humans, and highly corrosive, which has led to its gradual abandonment. Currently, there are mainly two methods for dealing with oxide scales: (1) Sandblasting: This involves using microglass beads to remove the black oxide scales from the surface. (2) Chemical method: This involves using a pollution-free pickling and passivation paste, along with a non-toxic cleaning solution containing inorganic additives at room temperature, to achieve the desired whitening effect. After treatment, the surface appears almost colorless. This method is particularly suitable for large and complex products. 1.2 Methods for giving a mirror-like finish to stainless steel surfaces: Depending on the complexity of the stainless steel product and the requirements of the customer, mechanical polishing, chemical polishing, or electrochemical polishing can be employed to achieve a mirror-like finish. 1.3 Surface coloring treatment: Coloring stainless steel not only allows for the creation of various colors in the products, thereby increasing their variety, but it also improves their wear resistance and corrosion resistance. There are several methods for coloring stainless steel: (1) Chemical oxidation coloring method； ⑵Electrochemical oxidation coloring method ； ⑶Ion deposition oxide coloring method ； ⑷High-temperature oxidation coloring method ； ⑸Gas-phase pyrolysis coloring method.