Comparison of two polishing methods for processing stainless steel parts Chemical polishing for processing stainless steel parts is a method of eliminating wear marks, etching and leveling by selectively dissolving the uneven areas on the surface of the sample by chemical reagents.
The electrochemical potentials of the constituent phases on the surface of the metal sample are different, and many micro-potentials are formed, which will cause uneven dissolution in the chemical solution. During the dissolution process, a layer of oxide film will be formed on the surface of the sample surface. Due to the thin mucous membrane of the protruding part of the sample surface, the dissolution and expansion speed of the metal is relatively slow. ideal requirement. When observed with a microscope at low and medium magnification, this small fluctuation is generally within the vertical discrimination capability of the objective lens, and a very clear histochemical polishing can still be observed. Step 1: Sample preparation: The sample is finely ground After cleaning. 2: Configure chemical polishing solution.
The chemical polishing solution for stainless steel parts processing should be prepared in a beaker. The chemical polishing solution formula should be selected according to the sample material. Distilled water should be used when preparing the solution, and chemically pure reagents should be used for pharmaceuticals.
Some medicines that are not easily soluble in water require heating of the solution to dissolve. Hydrogen peroxide and hydrofluoric acid are very corrosive, so pay attention to safety when preparing them. After the chemical polishing solution is used, the metal ions in the solution increase, and the polishing effect is weakened. If it is found that the effect is slow and the air bubbles are reduced, the new chemical solution should be replaced. 3: The sample is immersed in the polishing solution with bamboo clips or wooden clips, and it is stirred and taken out in time to observe until the polishing requirements are met. 4: After chemical polishing, the sample should be cleaned and dried immediately. Disadvantages of chemical polishing 1. The quality of chemical polishing is not as good as that of electrolytic polishing. 2. It is difficult to adjust and regenerate the solution used in chemical polishing, and its application is limited. 3. During the chemical polishing operation, nitric acid emits a large amount of yellow-brown harmful gas, which is very serious to environmental pollution.
The electrochemical polishing of stainless steel parts is grinding and polishing using the principle of metal electrochemical anode dissolution. The electrochemical pre-polishing and mechanical fine polishing are organically combined, and the two types of polishing characteristics of electrochemical and mechanism are brought into play.
It is not limited by the hardness and toughness of the material, and can polish workpieces of various complex shapes. The method is similar to electrolytic grinding. Advantages: The processed stainless steel is more mirror-like