Corrosion analysis of household hoses

Household bathroom toilets and water heaters and other bathroom facilities will use hoses. Corrosion of hoses is often the cause of headaches. Let's take a look at the causes of hose corrosion.

The metal reacts with oxygen in the atmosphere to form an oxide film on the surface. The iron oxide formed on the ordinary carbon steel continues to oxidize, causing the rust to continuously expand, eventually forming holes. The carbon steel surface can be ensured by electroplating with paint or oxidation-resistant metals (for example, zinc, nickel and chromium), but, as is known, this protection is only a thin film. If the protective layer is destroyed, the underlying steel begins to rust.

The corrosion resistance of stainless steel hoses depends on the chromium content. When the amount of chromium added is 10.5%, the atmospheric corrosion resistance of the steel increases significantly. However, when the chromium content is higher, although the corrosion resistance can still be improved, it is not obvious. . The reason is that the alloying treatment of steel with chromium changes the type of surface oxide to a surface oxide similar to that formed on pure chromium metal. This tightly adhered chromium-rich oxide protects the surface from further oxidation. This oxide layer is extremely thin, through which you can see the natural luster of stainless steel surface, so that stainless steel has a unique surface. Moreover, if the surface layer is damaged, the exposed steel surface reacts with the atmosphere to repair itself, and this “passivation film” is re-formed to continue protection.