The pitting corrosion of stainless steel ribbon is also called pitting corrosion or pitting corrosion. The pitting corrosion of stainless steel ribbon occurs in a specific corrosion medium. It usually occurs in solutions containing halogen anions and anions, among which chloride and bromide are the most corrosive. After corrosion, they are one of the common local corrosion of stainless steel.
1. We first understand the causes of pitting corrosion of stainless steel ribbon. When some active anions (such as Cl-) are contained in the medium, the destruction of passive film on stainless steel surface occurs. Because the passive film destroys the matrix, the metal is exposed to make it active, while the passive film is passive, thus forming an active passive corrosion battery. Because the area of the anode is much smaller than that of the cathode and the current density of the anode is high, the corrosion of the anode metal into small holes quickly becomes the cause of pitting corrosion of stainless steel bands.
2. What are the factors affecting pitting corrosion of stainless steel ribbons? The influence of medium. In addition to halide anions, oxidizing metal ions (such as Fe, Cu, Hg,) can also promote pitting; O in solution and other oxidants are the necessary conditions for pitting and the influence of alloy elements. Adding molybdenum to stainless steel can improve the stability of the film and make the surface of stainless steel form a dense and firm passivation. Film and chromium mainly improve the repair ability or regeneration ability of the passive film of steel.
3. How can we prevent pitting corrosion of stainless steel tie?
1) Choose austenitic stainless steel containing appropriate molybdenum and higher chromium.
2) Controlling the concentration of halogen ions in solution, especially C1-ion, and avoiding local concentration of solution;
3) Increasing the PH value of solution by adding corrosion inhibitor, and decreasing the temperature of medium, the higher the temperature, the more significant pitting corrosion.
4) There are other ways to prevent pitting corrosion of stainless steel tie, which requires different exploration, observation and summary of our practitioners.