The passivation film on the surface of 304 304L 316L Hot selling Stainless Steel Sheet mainly plays a protective role and delays rust and corrosion. However, during the actual application period, a lot of cables will destroy this passivation film, so that the surface of the steel strip will be damaged. The passive state is transformed into an active state, which in turn leads to a decrease in the corrosion resistance of the steel strip, causing the steel strip to rust and corrode. The following editors have sorted out several factors that will destroy the passive film on the surface of the steel strip. Let's take a look at the factors.
1. Chloride ion.
Studies have found that chloride ions are very harmful to steel strips. During the passivation process of the steel strip, the chloride ion content in the passivation solution should be strictly controlled.
Under normal circumstances, the chemical materials used for passivation have requirements on the content of chloride ions. When configuring the passivation solution, the amount of chloride ions in the water needs to be controlled. Even when cleaning, it is necessary to control the chloride ions in the water. Monitoring is carried out to ensure that the chloride ion content during passivation of the finished product is extremely low, so that the corrosion resistance of the steel strip can be maintained.
2. Surface cleanliness.
For 304 304L 316L Hot selling Stainless Steel Sheet, the smoother the surface is, the more difficult it is for foreign matter to adhere to it, so the probability of corrosion in various parts will be lower. On the contrary, if the surface of the steel sheet is relatively rough, then foreign matter It can be easily attached to it, and the foreign matter will cause the surface of the steel strip to corrode. Therefore, the surface of the steel strip should be finished.
In addition, the cleanliness of the surface of the steel strip has a great influence on corrosion. After passivation, cleaning is generally required. Care should be taken when cleaning. Once acid remains on the surface, the acid will promote the cathodic reaction. As a result, the passivation film on the surface is broken, the surface of the steel strip is activated, and the corrosion resistance performance is greatly reduced.
3. Use environmental media.
From the perspective of thermodynamic enzymes, the passive film is an inhibited metastable structure, and its actual protective effect is related to the environmental medium.
In actual use, it should be cleaned regularly, which helps to remove harmful substances on the surface and avoid harmful substances from adhering to it, thereby protecting the steel strip.
When 304 304L 316L Hot selling Stainless Steel Sheet is used in the environment containing chloride ions, it will accelerate the corrosion rate of the steel strip, especially when the steel strip is used in the food processing industry, it should be cleaned every time it comes into contact with mistakes , so as not to damage the passivation film by residual chloride ions on the surface of the steel strip.
For example, the containers and equipment used for processing dairy products are made of steel strips, so the chloride ions contained in the dairy products will destroy the passive film. If the containers or equipment are used to hold dairy products for a long time, it is easy to cause corrosion of the equipment. Perforation, so it needs to be cleaned regularly to ensure that the passivation film can continue to play a protective role.
4. The inherent factors of the steel strip itself.
The martensite content and chromium-nickel content in the steel strip have a relatively large influence on the passivation film. If the nickel content in the steel strip is relatively low, the passivation performance will decrease. Among them, the passivation film performance of martensitic steel strip is not as good as that of austenitic steel strip.
From the above content, we can know that the chloride ion in the steel strip, the cleanliness of the surface, the medium in the use environment and internal factors will destroy the passivation film on the surface of 304 304L 316L Hot selling Stainless Steel Sheet, which needs to be used in normal use. Be careful to avoid.