There are three main factors affecting stainless steel corrosion:
1. The content of alloying elements.
Generally speaking, steel with a chromium content of 10.5% is less likely to rust.
The higher the chromium and nickel content, the better the corrosion resistance. For example, the nickel content of 304 material is 8-10%, and the chromium content reaches 18-20%. Such stainless steel will not rust under normal circumstances.
2. The smelting process of the production company will also affect the corrosion resistance of stainless steel.
Large stainless steel plants with good smelting technology, advanced equipment and advanced processes can ensure the control of alloy elements, removal of impurities and control of billet cooling temperature. Therefore, the product quality is stable and reliable, with good intrinsic quality and not easy to rust.On the contrary, some small steel plants have backward equipment and backward processes. During the smelting process, impurities cannot be removed, and the products produced will inevitably rust.
3. External environment, dry climate and good ventilation are not easy to rust.
However, areas with high air humidity, continuous rainy weather, or environments with high pH in the air are prone to rust.
Made of 304 stainless steel, it will rust if the surrounding environment is too poor.
How to deal with rust spots on stainless steel?
1. Chemical method
Use pickling paste or spray to assist in re-passivating the rusted parts to form a chromium oxide film to restore corrosion resistance.
After pickling, it is important to rinse properly with clean water in order to remove all contaminants and acid residues.
After all processing, use polishing equipment to polish again and seal with polishing wax.
If there are slight rust spots locally, you can use a 1:1 mixture of gasoline and engine oil to wipe off the rust spots with a clean rag.
2. Mechanical method
Sandblasting, blasting with glass or ceramic particles, obliterating, brushing and polishing.
It is possible to mechanically remove contamination from previously removed material, polished material or buried material.
All kinds of contamination, especially foreign iron particles, can be a source of corrosion, especially in humid environments.
Therefore, mechanically cleaned surfaces should be cleaned regularly under dry conditions.
The use of mechanical methods can only clean the surface and cannot change the corrosion resistance of the material itself.
Therefore, it is recommended to re-polishing with polishing equipment after mechanical cleaning and sealing with polishing wax.
