Surface treatment technology of
stainless steel forgings is an important means to improve the appearance and performance of products. This paper will introduce the main methods of polishing stainless steel surface, analyze their advantages and disadvantages and scope of application, and provide reference for choosing the appropriate treatment methods.
Stainless steel forgings in the process of processing, after rolling, binding, welding or artificial heating treatment, the surface may produce black oxide. This oxide, usually composed of titanium dioxide (TiO₂) and nickel dioxide (NiO₂), is hard and difficult to remove. Traditionally, these rind are removed by strong corrosives such as hydrofluoric acid and nitric acid, but this method is not only costly, but also has a negative impact on the environment and human health, and is gradually phased out. The current processing methods mainly have the following two:
The black oxide on the surface is removed by spraying microglass beads. This method is suitable for the removal of heavy oxide layer, the effect is remarkable, especially suitable for the treatment of large area flat surface.
The use of pollution-free pickling passivation paste and non-toxic cleaning liquid at room temperature for immersion. This method is not only environmentally friendly, but also can effectively remove the oxide, so that the stainless steel can restore the original white luster. The treated surface usually presents a dull tone, suitable for the handling of large and complex products.
Mirror bright treatment can make the stainless steel surface to achieve a high degree of gloss, mainly including mechanical polishing, chemical polishing and electrochemical polishing three methods. They each have different advantages and disadvantages and scope of application.
Mechanical polishing has good flatness and can achieve high brightness. However, its labor intensity is large, the process pollution is serious, the processing of complex parts is not easy, the luster durability is poor, and the investment and cost are high. It is suitable for simple workpieces and small and medium-sized products, not suitable for complex parts, especially products with low gloss requirements.
The main advantages of chemical polishing are less investment, high efficiency and fast processing of complex parts. However, its brightness is relatively insufficient, the polishing fluid needs to be heated and there is gas overflow, so it needs to be equipped with ventilation equipment. It is suitable for complex products and small batch processing with low brightness requirements, and has good economy.
Electrochemical polishing can achieve mirror luster, and long-term maintenance, process stability, less pollution, low cost, good anti-pollution. However, it has a large one-time investment, requires assembly tooling and auxiliary electrodes when processing complex parts, and needs to be cooled for mass production. It is suitable for high-grade small and medium-sized products and products requiring long-term mirror brightness, the process is stable, suitable for widespread use.
Stainless steel coloring can not only give the product a variety of colors, but also improve its wear and corrosion resistance. Common coloring methods include:
In a specific solution, a color film is formed by chemical oxidation. Commonly used are dichromate method, mixed sodium salt method, vulcanization method, acid oxidation method and alkaline oxidation method. In particular, the "INCO" method is widely used, but in order to ensure consistent color, it is usually necessary to use a reference electrode for control.
In a specific solution, a color film is formed by electrochemical oxidation. This method can precisely control the color, but requires more complex equipment and processes.
Ion Deposition Oxide Coloring Method: vacuum evaporation coating in a vacuum coating machine, such as titanium plated watch cases. This method is suitable for mass production, but due to large investment and high cost, small batch products are not economical.
In a specific molten salt, the workpiece is immersed and kept under certain process parameters, so that the workpiece forms an oxide film of different thickness, thus showing a variety of colors.
Each treatment method has its own unique advantages and application scenarios, and the choice of the appropriate treatment method can be determined according to the specific product requirements and use environment.
By understanding the various methods of polishing the stainless steel surface mirror, you can better choose the treatment technology suitable for the specific product needs. Mechanical polishing is suitable for simple workpieces with its excellent brightness, but the labor intensity and cost are high; Chemical polishing is favored for its high efficiency and low cost in handling complex parts, although brightness and processing environment require additional attention; Electrochemical polishing, with its long-lasting gloss and low pollution, is suitable for long-term applications of high-end products. According to the specific production requirements and budget considerations, choosing the most appropriate treatment method will help improve the overall quality and market competitiveness of stainless steel products.
