runyijia industries logo

Why is stainless steel rust?

When the surface of a stainless steel tube brown Xiuban (point), people greatly surprised that “stainless steel is not rusty, rust is not stainless steel, steel may be a problem.” In fact, this is the lack of understanding of a stainless steel one-sided view of the error. Stainless steel under certain conditions will be rusty.

Stainless steel has the ability to resist oxidation of the atmosphere – that is stainless steel, but also with the Hansuan, alkali, salt corrosion is the medium – that is the ability of corrosion resistance. However, its corrosion resistance is the size of steel with its own chemical composition, increase mutual status, conditions of use and environmental changes in the type of media. Such as the 304 steel pipe, in dry clean the atmosphere, it is absolutely excellent anti-corrosion ability, but  move it to the waterfront area, contains a lot of salt in the sea mist, will soon be a rusty, and the good performance of 316 steel pipe . Therefore, not any one of stainless steel, in any environment under capability corrosion, not rusty.

Stainless steel is formed on the surface of an extremely thin and the stability of the fine solid chromium-rich oxide film (protective film), to prevent the infiltration of oxygen atoms, to oxidation, and the ability to obtain anti-corrosion. Once there are some reasons, this film has been constantly undermined, in air or liquid oxygen atoms will continue to infiltrate into or metal atoms of iron to keep out from the out, the loose formation of iron oxide, the metal surface will continue to be rusty. This surface film in the form of a lot of damage, the daily life of several situations as below:

1. Stainless steel surface of the plot with other metals or dust particles heterogeneous metal fixtures, in the humid air, stainless steel fixtures and the condensed water, both as a single-cell, triggered the electrochemical reaction. The film has been destroyed; known that the electrochemical corrosion.
2. Stainless steel surface adhesion organic juice (such as vegetables, noodle soup, sputum, etc..), oxygen in the water under the circumstances, constitutes organic acids, organic acids are long on the surface of metal corrosion.
3. Stainless steel surface adhesion containing acid, alkaline, salt material (such as wall decoration of wall decoration alkaline, lime splash), caused localized corrosion.
4. Polluting the air (for example, contains a lot of sulfide, carbon monoxide, nitrogen oxides in the atmosphere), the case of condensed water to form sulphuric acid, nitric acid, acetic acid solution, cause chemical corrosion.

Above the surface of stainless steel can be caused by the protective membrane damage caused corrosion. Therefore, in order to ensure permanent bright metal surface, not rust, we recommend:
1. Decorative stainless steel must always be on the scrub clean the surface, removing fixtures, the elimination of the sale of the modified external factors.
2. Waterfront to the use of 316 stainless steel material, 316 water corrosion resistant materials.
3. Stainless steel market, some of the chemical constituents can not meet the relevant national standards, amounted to less than 304 material requirements. So it will lead to rust, which requires the user to choose a serious credibility of the product manufacturers.

Leave a Reply


captcha *