1 Introduction

      Stainless steel surface finishing treatment technology is divided into matte treatment technology, mirror bright treatment technology, and surface color treatment technology. At present, these process technologies have achieved excellent results in different products and different fields.

2. Application of stainless steel matte treatment technology

      The stainless steel matte treatment technology means that the processed and formed products achieve a uniform silver-white color, which is consistent with the color and luster of the stainless steel itself, and has a metallic luster. This generally refers to the production of large-scale stainless steel products. Because large-scale stainless steel parts undergo the process of rolling, stamping, hemming and welding, the surface of the processed workpiece has weld seams, oil stains, rust, yellow spots, etc., which are not beautiful and easy to rust. , reducing the quality and value of its stainless steel products.

      In order to make stainless steel products look beautiful and popular with customers, it is necessary to carry out surface finishing processing on stainless steel products. Large-scale stainless steel products are generally treated with matte after forming, but the parts can also be pretreated before processing, and then post-processing can be done after compounding. After this treatment, it can not only achieve a beautiful appearance, but also improve its anti-corrosion and anti-discoloration properties. It can also be sandblasted first and then pickled and passivated to achieve the purpose of matte.

      After the above method, the corrosion resistance of stainless steel products can be increased by 2 to 3 times. The reason why stainless steel does not rust is mainly due to the presence of chromium and nickel. After matt treatment, it can not only eliminate the impurities contained in the stainless steel matrix and the iron-rich layer on the surface, but also enrich chromium and nickel on the surface to form a complete Purification membrane, play a better anti-corrosion effect.

3. Application of stainless steel mirror bright treatment technology

      According to the complexity of stainless steel products and different user requirements, mechanical polishing, chemical polishing, electrochemical polishing and other methods can be used to achieve mirror gloss. The following author introduces the advantages and disadvantages of these three process methods, for your reference and selection, see Table 1.

Table 1 Advantages and disadvantages of three polishing processes

project

Method Advantages Disadvantages Applicable Product Notes

      Good mechanical polishing and leveling, bright labor intensity, serious pollution, complex and unprocessable, reduced luster, easy to rust, high investment and cost Simple parts, medium and small products with inconsistent luster, short luster retention time, dullness , Less investment in rusted chemical polishing, complex parts can be polished, fast speed, high efficiency, good corrosion resistance, poor brightness, gas overflow, need ventilation equipment, difficult to heat complex parts and small parts with low brightness requirements. The processing of batch products is more cost-effective than electrochemical polishing, the mirror gloss can be maintained for a long time, the process is stable, the pollution is less, the cost is low, the corrosion resistance is good, the pollution resistance is high, the one-time investment is large, the complex parts need tooling, auxiliary electrodes, and high-end products with cooling facilities are required for mass production. , export products, products with tolerances, stable process, mass production, easy operation and control, worthy of promotion and use

      The following author focuses on the characteristics of the electrochemical polishing process of mirror bright. Stainless steel uses DC current to pass through a specific electrolyte and transfer it to the conductor of the opposite pole, so that a layer of metal is removed from the surface of the stainless steel part on the anode, so that the uneven surface can reach a flat and bright surface, which is called stainless steel electrochemical treatment technology - Electrochemical polishing.

      The process of electrochemical brightening of stainless steel is that the metal anode dissolves, the anode forms an oxide film and the anode releases oxygen at the same time. Therefore, electrochemical brightening treatment has no hydrogen embrittlement on stainless steel products and various metal components.

      The stainless steel products that have undergone electrochemical brightening treatment can maintain the original geometric shape of the product, the brightness and cleanliness of the product can be maintained for more than 2 years without distortion, and the fine burrs on the product can be removed at the same time, especially suitable for vulnerable parts and difficult to reach. Dehairing of areas such as precision lathe parts, optics, motors, electronic parts and household appliances, etc.

      Electrochemical bright treatment technology can also remove micro-cracks and embedded foreign impurities on the surface of the part while deburring. It has no energy input to the surface of the part, that is, the surface with tensile and compressive stress can become a stress-free surface, thereby improving the product quality. Fatigue resistance.

      The corrosion resistance of stainless steel products can be improved by 2-3 times after electrochemical bright treatment. Because the stainless steel is electrochemically treated with chromium-nickel oxide to form a strengthened passivation film, the chromium-poor nickel-poor layer on the surface of the stainless steel is solved, and an enriched chromium and nickel passivation layer is formed.

      After the stainless steel products are treated with electrochemical brightening, the cleanliness of the products is improved. Because the surface of the workpiece after electrochemical treatment is bright and smooth, dirt is not easy to stick to its surface. For example, the electric heating tube in the water heater is in the water for a long time, and the calcium and magnesium impurities in the water are easy to condense on the tube and erode the tube and cause perforation. However, after the electrochemical brightening treatment, the scale is not easy to form, which greatly improves its service life.

Another example is pharmaceutical equipment, all surfaces in contact with pharmaceuticals must have higher requirements for cleaning, cleanliness and corrosion resistance. Electrochemical bright treatment technology can meet this requirement, and it is one of the process technologies that must be used in pharmaceutical equipment.

4. Application of stainless steel color processing technology

       Color stainless steel treatment technology, from the process point of view, there are chemical methods and electrochemical methods. They can get different colors when they are treated in specific electrolytes, thereby improving the wear resistance, corrosion resistance and color varieties of stainless steel. They are used in different occasions and get different economic benefits.

       There are several ways to make colored stainless steel: ① high temperature oxidation method, ② chemical oxidation method, ③ electrochemical oxidation method, ④ ion implantation method, ⑤ gas phase cracking method.

An overview of the various treatment methods is as follows:

      (1) The high temperature oxidation method is to immerse the workpiece in a specific molten salt and maintain a certain process temperature and time, so that the workpiece forms an oxide film of a certain thickness, showing various colors.

      (2) The chemical oxidation method is to form the color of various films in a specific solution by controlling the temperature and time. Generally, the "inco method" is used more. However, if the color and luster of the product can be kept consistent, a reference electrode must be used to control the color of the film. .

      (3) Electrochemical method is to form the color of a certain thickness of chlorinated film in a specific electrolyte by controlling temperature, voltage and time. This process is relatively mature and widely used.

      (4) The ion implantation method is to deposit ions on the surface of stainless steel by vaporizing ions in a vacuum. For example, the watch case on the market, the golden color of the strap adopts this process technology, which is suitable for mass production.

      (5) Gas-phase cracking method, the process is more complicated, and the industrial application is relatively small, so this article will not elaborate.

5 Conclusion

      (1) After the above-mentioned surface treatment of stainless steel parts, its corrosion resistance can be increased by 2-3 times, it can be deburred, its anti-stick performance can be improved, and its appearance can be beautiful and refined, giving people a gorgeous and noble feeling.

      (2) After the above surface treatment, the stainless steel parts can meet the special requirements of some products, improve product quality, prolong the service life of equipment, improve market competitiveness, and bring better economic benefits to enterprises.