Stainless steel building material is a metal that is not easy to rust, but it is not a metal that will never rust. Depending on the conditions of use or the environment in which it is used, it may also be polluted and rusted. Don’t think that stainless steel building materials don’t rust, just ignore daily maintenance, wait until the pollution and rust are the most serious, and then take cleaning measures in a hurry. This kind of measure is the worst policy.
Stainless steel products have excellent corrosion resistance and are not easy to rust. As mentioned earlier, they contain chromium. In the air, it combines with oxygen to form a solid surface and forms a dense non-oxidizing film. This non-oxidizing film can prevent the oxidation (rust) of the steel surface, and can protect the surface to prevent corrosion from various corrosion factors. . Therefore, if the film is damaged due to some corrosion, and it is placed in a place where chromium and oxygen cannot combine, the stainless steel building material will start to rust.
However, as long as the cause of corrosion is eliminated and chromium can be combined with oxygen, the non-oxidizing film will be produced again, and its corrosion resistance function will be restored.
There are many reasons for stainless steel building materials to be polluted and rusted, but generally speaking, they are all caused by the adhesion, accumulation, and adhesion of salt contained in the sea breeze due to the components in the floating iron powder or harmful gases in the atmosphere. These attachments will gradually accumulate and be fixed with moisture, which will destroy the non-oxidized film on the surface of the stainless steel building material and hinder the regeneration of the film, so the stainless steel building material will begin to rust. The initial state of this rust is relatively simple to remove, and the original state can be restored. Even after long-term storage, it can be restored to a slightly different appearance than the original condition as long as proper cleaning is done. It can be seen that the rust of stainless steel building materials is only the surface, not the corrosion of the material itself. This is fundamentally different from the rusting of raw steel and aluminum.
Therefore, stainless steel building materials sometimes get rusty, but as long as they are maintained regularly, they can always maintain the original beauty of stainless steel building materials.
Causes of rust and pollution
- When road construction, construction engineering, or various vehicles are traveling, they are attached by the scattered soil, sand, dust, iron powder, etc.
- When polluted by harmful substances such as sulfurous acid gas contained in the exhaust of automobiles and buses.
- It is polluted by the dust and harmful components in the exhaust gas discharged from various industrial and mining waste incineration, heating and cooling of buildings, etc.
- Polluted by corrosive gases produced by hot springs.
- Adhesion pollution by salt contained in coastal sea breeze.
- Contaminated by cleaning liquid adhesion. Contaminated by hand prints and hand dirt.
- 7. Contamination by mucous membranes used for surface protection.
1. When rusted due to adhesion of dissimilar metals
When the “incidental rust” caused by iron powder, etc. or the situation is not serious, the rust can be easily removed by wiping with a sponge or cloth, plus a neutral detergent or soapy water. Then rinse with water, be careful not to let the lotion stay on it. This level of rust removal, as long as the removal work is done immediately, it is not only easy to maintain, but also more effective, and the removal cost is also very cheap.
But if it is left alone, a mixture of iron hydroxide, iron oxide, iron sulfite, etc. will be formed soon, and it will show a serious rusty state of dark brown. In this case, it can be completely cleaned with a commercially available stainless steel cleaning solution or a 15℅ dilution of nitric acid. However, there are also rusts that cannot be eliminated, and at the same time, it will damage the stainless steel surface to some extent, or damage the stainless steel. At this time, use sandpaper or a stainless steel brush to grind and wipe, and then clean it with a cleaning solution.
2. Rust caused by harmful components in the attached exhaust gas
In the factory area, or in the environment with heavy traffic in the city, the surface of stainless steel is easily polluted, and sometimes there will be small spots of rust. Most of these conditions are caused by the harmful components contained in the exhaust of automobiles, air conditioners, or factory exhaust. At this time, when the pollution is slight, neutral detergent or soapy water can be used to clean it completely, but it is not easy to deal with it when it is serious. In this case, use the same maintenance method as in Item 1 above to remove it. In this environment, as far as possible, 2-3 times a year, a comprehensive regular cleaning of the surface is required, and at least one regular cleaning is absolutely necessary.
3. Rust caused by attached salt
SUS 304 stainless steel will also produce red rust in a short period of time when it is blown by sea breeze on the front of the coast.
Moreover, it rusts faster than other areas, and the treatment method is the same as that of 1.
Coastal areas hope to use SUS 316, which is more corrosion-resistant, as stainless steel when adopting stainless steel exterior.
As for the use of SUS 304 for stainless steel exterior, try to do regular cleaning 3-4 times a year.
4. Rust caused by adhesion of cleaning solution
If it cannot be removed with a neutral detergent, use a cleaning solution to remove it.
5. Rust caused by hand dirt or fingerprints
If it cannot be removed with a neutral cleaning agent, use a sponge, cloth, etc. to soak in an organic solvent (alcohol, benzine, acetone, etc.) to wipe. If this method still cannot be completely removed, use a cleaning solution for stainless steel to remove it. total
In other words, after cleaning with various cleaning methods, it must be rinsed with water again.
6. Pollution caused by surface protective film
Use a sponge, cloth dampened with water-soluble neutral detergent, or alcohol to wipe. If still invalid, use
Thinner, light olein to remove. Rinse thoroughly with clean water after washing.
- The causes and situations of pollution and rust of stainless steel building materials are completely different for each situation, so the most suitable maintenance method must be adopted in accordance with each situation.
- When using a cleaning solution to remove pollution and rust, please do a partial “trial wipe” in advance to confirm the cleaning effect. If the test results are satisfactory, follow this method to do a comprehensive cleaning. The cleaning should not only pollute the rusty part, but also clean the surrounding parts as much as possible. If this is not done, the luster of the stainless steel surface will be uneven, which will be ugly in appearance.
- After using the cleaning solution, it must be completely cleaned with clean water. Be careful not to allow the solution to remain on the stainless steel surface, otherwise it will cause rust. Washing off the liquid medicine can cause roughness or rashes on the hands. Therefore, please wear rubber gloves before use.
- When using a cloth, loofah, nylon sponge, brush hook, or brush for cleaning, it must be cleaned along the stainless steel grinder. If you do circular cleaning, the pollution is not easy to remove, and it will damage the glossy lines of the surface, making it ugly.
Cleaning tools made of steel, such as cleaning agents with rough textures, or the use of sandpaper, although they can remove serious pollution, are absolutely prohibited in general, because they will damage the surface of stainless steel and adhere to iron powder to form rust.