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FOSHAN FEROSTEEL CO., LTD

FOSHAN FEROSTEEL CO., LTD
FOSHAN FEROSTEEL CO., LTD

FOSHAN FEROSTEEL CO., LTD

FOSHAN FEROSTEEL CO., LTD
FOSHAN FEROSTEEL CO., LTD

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FOSHAN FEROSTEEL CO., LTD
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Stainless Steel Pickling Principle
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Stainless Steel Pickling Principle

  • Categories:Industry news
  • Author:Ferosteel
  • Origin:Ferosteel
  • Time of issue:2020-05-19 10:38
  • Views:

(Summary description)    The corrosion resistance of stainless steel mainly depends on the surface passivation film. If the film is incomplete or defective, stainless steel will still be corroded. In engineering, pickling and passivation treatment is usually carried out to make the corrosion resistance of stainless steel play a greater role.     The corrosion resistance of stainless steel is mainly due to the surface covered with a very thin (about 1nm) dense passivation film. This layer of 1n corrosion medium isolation is the basic barrier for stainless steel protection. The passivation of stainless steel has dynamic characteristics. It should not be considered that the corrosion has completely stopped, but that it forms a diffusion barrier, which greatly reduces the anode reaction rate. Usually in the presence of reducing agents (such as chloride ions) tend to damage the membrane, and in the presence of oxidizing agents (such as air) can maintain or repair the membrane.     A stainless steel workpiece placed in the air will form an oxide film, but the protection of this film is not perfect. Generally, thorough cleaning is required, including alkaline cleaning and pickling, and then passivation with an oxidizing agent can ensure the integrity and stability of the passivation film. One of the purposes of pickling is to create favorable conditions for passivation treatment and ensure the formation of a high-quality passivation film. Because the surface of the stainless steel surface is corroded by an average of 10 μm by acid washing, the chemical activity of the acid solution makes the dissolution rate of the defective part higher than that of other parts on the surface, so the acid washing can make the entire surface tend to be evenly balanced. The hidden dangers that easily cause corrosion are eliminated.     But more importantly, through acid pickling and passivation, the iron and iron oxides are preferentially dissolved than the chromium and chromium oxides, and the chromium-depleted layer is removed, resulting in chromium enrichment on the surface of stainless steel. This chromium-rich passivation film The potential can reach + 1.0V (SCE), which is close to the potential of precious metals, which improves the stability of corrosion resistance. Different passivation treatments will also affect the composition and structure of the film, thereby affecting the rust. For example, through electrochemical modification, the passivation film can have a multilayer structure, forming CrO3 or Cr2O3 in the barrier layer, or forming a glassy state The oxide film allows stainless steel to exert maximum corrosion resistance.

Stainless Steel Pickling Principle

(Summary description)    The corrosion resistance of stainless steel mainly depends on the surface passivation film. If the film is incomplete or defective, stainless steel will still be corroded. In engineering, pickling and passivation treatment is usually carried out to make the corrosion resistance of stainless steel play a greater role.

    The corrosion resistance of stainless steel is mainly due to the surface covered with a very thin (about 1nm) dense passivation film. This layer of 1n corrosion medium isolation is the basic barrier for stainless steel protection. The passivation of stainless steel has dynamic characteristics. It should not be considered that the corrosion has completely stopped, but that it forms a diffusion barrier, which greatly reduces the anode reaction rate. Usually in the presence of reducing agents (such as chloride ions) tend to damage the membrane, and in the presence of oxidizing agents (such as air) can maintain or repair the membrane.

    A stainless steel workpiece placed in the air will form an oxide film, but the protection of this film is not perfect. Generally, thorough cleaning is required, including alkaline cleaning and pickling, and then passivation with an oxidizing agent can ensure the integrity and stability of the passivation film. One of the purposes of pickling is to create favorable conditions for passivation treatment and ensure the formation of a high-quality passivation film. Because the surface of the stainless steel surface is corroded by an average of 10 μm by acid washing, the chemical activity of the acid solution makes the dissolution rate of the defective part higher than that of other parts on the surface, so the acid washing can make the entire surface tend to be evenly balanced. The hidden dangers that easily cause corrosion are eliminated.

    But more importantly, through acid pickling and passivation, the iron and iron oxides are preferentially dissolved than the chromium and chromium oxides, and the chromium-depleted layer is removed, resulting in chromium enrichment on the surface of stainless steel. This chromium-rich passivation film The potential can reach + 1.0V (SCE), which is close to the potential of precious metals, which improves the stability of corrosion resistance. Different passivation treatments will also affect the composition and structure of the film, thereby affecting the rust. For example, through electrochemical modification, the passivation film can have a multilayer structure, forming CrO3 or Cr2O3 in the barrier layer, or forming a glassy state The oxide film allows stainless steel to exert maximum corrosion resistance.

  • Categories:Industry news
  • Author:Ferosteel
  • Origin:Ferosteel
  • Time of issue:2020-05-19 10:38
  • Views:
Information

    The corrosion resistance of stainless steel mainly depends on the surface passivation film. If the film is incomplete or defective, stainless steel will still be corroded. In engineering, pickling and passivation treatment is usually carried out to make the corrosion resistance of stainless steel play a greater role.

    The corrosion resistance of stainless steel is mainly due to the surface covered with a very thin (about 1nm) dense passivation film. This layer of 1n corrosion medium isolation is the basic barrier for stainless steel protection. The passivation of stainless steel has dynamic characteristics. It should not be considered that the corrosion has completely stopped, but that it forms a diffusion barrier, which greatly reduces the anode reaction rate. Usually in the presence of reducing agents (such as chloride ions) tend to damage the membrane, and in the presence of oxidizing agents (such as air) can maintain or repair the membrane.

    A stainless steel workpiece placed in the air will form an oxide film, but the protection of this film is not perfect. Generally, thorough cleaning is required, including alkaline cleaning and pickling, and then passivation with an oxidizing agent can ensure the integrity and stability of the passivation film. One of the purposes of pickling is to create favorable conditions for passivation treatment and ensure the formation of a high-quality passivation film. Because the surface of the stainless steel surface is corroded by an average of 10 μm by acid washing, the chemical activity of the acid solution makes the dissolution rate of the defective part higher than that of other parts on the surface, so the acid washing can make the entire surface tend to be evenly balanced. The hidden dangers that easily cause corrosion are eliminated.

    But more importantly, through acid pickling and passivation, the iron and iron oxides are preferentially dissolved than the chromium and chromium oxides, and the chromium-depleted layer is removed, resulting in chromium enrichment on the surface of stainless steel. This chromium-rich passivation film The potential can reach + 1.0V (SCE), which is close to the potential of precious metals, which improves the stability of corrosion resistance. Different passivation treatments will also affect the composition and structure of the film, thereby affecting the rust. For example, through electrochemical modification, the passivation film can have a multilayer structure, forming CrO3 or Cr2O3 in the barrier layer, or forming a glassy state The oxide film allows stainless steel to exert maximum corrosion resistance.

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