2022

Why does stainless steel spring have corrosion resistance?

Author

2022-03-31 10:11

All metals react with oxygen in the atmosphere to form an oxide film on their surface. Unfortunately, the iron oxide formed on ordinary carbon steel will continue to oxidize, leading to the expansion of corrosion, and finally forming holes. The surface of carbon steel can be protected by coating with paint or anti-oxidation metals (such as zinc, nickel and chromium), but as we all know, this protection is only a thin film. If the protective layer is damaged, the steel below will start to rust.
The corrosion resistance of stainless steel depends on chromium, but because chromium is one of the components of steel, the protection methods are also different. When the chromium content reaches 105%, the atmospheric corrosion resistance of steel is significantly improved, but the higher the chromium content, the less obvious the improvement of corrosion resistance of steel. The reason is that alloying steel and chromium change the type of surface oxide formation similar to pure chromium metal. This tightly adhered chromium-rich oxide protects the surface from further oxidation. This kind of oxide layer is very thin, through which you can see the natural luster of the steel surface, giving stainless steel a unique surface
In addition, if the surface is damaged, the exposed steel surface will react with the atmosphere to repair itself, so that the "passive film" can be formed again and continue to play its protective role. Therefore, all stainless steels have a common feature, that is, the chromium content is more than 10.5%.
To sum up, stainless steel springs have good corrosion resistance, so stainless steel springs are used more and more in daily life!